final class Map4[K, +V] extends AbstractMap[K, V] with StrictOptimizedIterableOps[(K, V), Iterable, Map[K, V]] with Serializable
- Alphabetic
- By Inheritance
- Map4
- Serializable
- StrictOptimizedIterableOps
- AbstractMap
- Map
- MapOps
- Iterable
- AbstractMap
- Map
- Equals
- MapFactoryDefaults
- MapOps
- PartialFunction
- Function1
- AbstractIterable
- Iterable
- IterableFactoryDefaults
- IterableOps
- IterableOnceOps
- IterableOnce
- AnyRef
- Any
- by UnliftOps
- by iterableOnceExtensionMethods
- by any2stringadd
- by StringFormat
- by Ensuring
- by ArrowAssoc
- Hide All
- Show All
- Public
- Protected
Instance Constructors
- new Map4(key1: K, value1: V, key2: K, value2: V, key3: K, value3: V, key4: K, value4: V)
Value Members
- def +[V1 >: V](kv: (K, V1)): Map[K, V1]
Alias for
updated
- def ++[V2 >: V](xs: IterableOnce[(K, V2)]): Map[K, V2]
Alias for
concat
Alias for
concat
- Definition Classes
- MapOps
- final def ++[B >: (K, V)](suffix: IterableOnce[B]): Iterable[B]
Alias for
concat
Alias for
concat
- Definition Classes
- IterableOps
- Annotations
- @inline()
- final def -(key: K): Map[K, V]
Alias for
removed
- final def --(keys: IterableOnce[K]): Map[K, V]
Alias for
removedAll
- def addString(sb: mutable.StringBuilder, start: String, sep: String, end: String): mutable.StringBuilder
Appends all elements of this map to a string builder using start, end, and separator strings.
Appends all elements of this map to a string builder using start, end, and separator strings. The written text begins with the string
start
and ends with the stringend
. Inside, the string representations (w.r.t. the methodtoString
) of all elements of this map are separated by the stringsep
.Example:
scala> val a = List(1,2,3,4) a: List[Int] = List(1, 2, 3, 4) scala> val b = new StringBuilder() b: StringBuilder = scala> a.addString(b , "List(" , ", " , ")") res5: StringBuilder = List(1, 2, 3, 4)
- start
the starting string.
- sep
the separator string.
- end
the ending string.
- returns
the string builder
b
to which elements were appended.
- Definition Classes
- MapOps → IterableOnceOps
- final def addString(b: mutable.StringBuilder): mutable.StringBuilder
Appends all elements of this collection to a string builder.
Appends all elements of this collection to a string builder. The written text consists of the string representations (w.r.t. the method
toString
) of all elements of this collection without any separator string.Example:
scala> val a = List(1,2,3,4) a: List[Int] = List(1, 2, 3, 4) scala> val b = new StringBuilder() b: StringBuilder = scala> val h = a.addString(b) h: StringBuilder = 1234
- b
the string builder to which elements are appended.
- returns
the string builder
b
to which elements were appended.
- Definition Classes
- IterableOnceOps
- Annotations
- @inline()
- final def addString(b: mutable.StringBuilder, sep: String): mutable.StringBuilder
Appends all elements of this collection to a string builder using a separator string.
Appends all elements of this collection to a string builder using a separator string. The written text consists of the string representations (w.r.t. the method
toString
) of all elements of this collection, separated by the stringsep
.Example:
scala> val a = List(1,2,3,4) a: List[Int] = List(1, 2, 3, 4) scala> val b = new StringBuilder() b: StringBuilder = scala> a.addString(b, ", ") res0: StringBuilder = 1, 2, 3, 4
- b
the string builder to which elements are appended.
- sep
the separator string.
- returns
the string builder
b
to which elements were appended.
- Definition Classes
- IterableOnceOps
- Annotations
- @inline()
- def andThen[C](k: PartialFunction[V, C]): PartialFunction[K, C]
Composes this partial function with another partial function that gets applied to results of this partial function.
Composes this partial function with another partial function that gets applied to results of this partial function.
Note that calling isDefinedAt on the resulting partial function may apply the first partial function and execute its side effect. It is highly recommended to call applyOrElse instead of isDefinedAt / apply for efficiency.
- C
the result type of the transformation function.
- k
the transformation function
- returns
a partial function with the domain of this partial function narrowed by other partial function, which maps arguments
x
tok(this(x))
.
- Definition Classes
- PartialFunction
- def andThen[C](k: (V) => C): PartialFunction[K, C]
Composes this partial function with a transformation function that gets applied to results of this partial function.
Composes this partial function with a transformation function that gets applied to results of this partial function.
If the runtime type of the function is a
PartialFunction
then the otherandThen
method is used (note its cautions).- C
the result type of the transformation function.
- k
the transformation function
- returns
a partial function with the domain of this partial function, possibly narrowed by the specified function, which maps arguments
x
tok(this(x))
.
- Definition Classes
- PartialFunction → Function1
- def apply(key: K): V
Retrieves the value which is associated with the given key.
Retrieves the value which is associated with the given key. This method invokes the
default
method of the map if there is no mapping from the given key to a value. Unless overridden, thedefault
method throws aNoSuchElementException
.- key
the key
- returns
the value associated with the given key, or the result of the map's
default
method, if none exists.
- def applyOrElse[K1 <: K, V1 >: V](x: K1, default: (K1) => V1): V1
Applies this partial function to the given argument when it is contained in the function domain.
Applies this partial function to the given argument when it is contained in the function domain. Applies fallback function where this partial function is not defined.
Note that expression
pf.applyOrElse(x, default)
is equivalent toif(pf isDefinedAt x) pf(x) else default(x)
except that
applyOrElse
method can be implemented more efficiently. For all partial function literals the compiler generates anapplyOrElse
implementation which avoids double evaluation of pattern matchers and guards. This makesapplyOrElse
the basis for the efficient implementation for many operations and scenarios, such as:- combining partial functions into
orElse
/andThen
chains does not lead to excessiveapply
/isDefinedAt
evaluation lift
andunlift
do not evaluate source functions twice on each invocationrunWith
allows efficient imperative-style combining of partial functions with conditionally applied actions
For non-literal partial function classes with nontrivial
isDefinedAt
method it is recommended to overrideapplyOrElse
with custom implementation that avoids doubleisDefinedAt
evaluation. This may result in better performance and more predictable behavior w.r.t. side effects.- x
the function argument
- default
the fallback function
- returns
the result of this function or fallback function application.
- Definition Classes
- MapOps → PartialFunction
- combining partial functions into
- def canEqual(that: Any): Boolean
A method that should be called from every well-designed equals method that is open to be overridden in a subclass.
A method that should be called from every well-designed equals method that is open to be overridden in a subclass. See Programming in Scala, Chapter 28 for discussion and design.
- that
the value being probed for possible equality
- returns
true if this instance can possibly equal
that
, otherwise false
- def collect[B](pf: PartialFunction[(K, V), B]): Iterable[B]
Builds a new iterable collection by applying a partial function to all elements of this iterable collection on which the function is defined.
Builds a new iterable collection by applying a partial function to all elements of this iterable collection on which the function is defined.
- B
the element type of the returned iterable collection.
- pf
the partial function which filters and maps the iterable collection.
- returns
a new iterable collection resulting from applying the given partial function
pf
to each element on which it is defined and collecting the results. The order of the elements is preserved.
- Definition Classes
- StrictOptimizedIterableOps → IterableOps → IterableOnceOps
- def collect[K2, V2](pf: PartialFunction[(K, V), (K2, V2)]): Map[K2, V2]
Builds a new collection by applying a partial function to all elements of this map on which the function is defined.
Builds a new collection by applying a partial function to all elements of this map on which the function is defined.
- K2
the key type of the returned map.
- V2
the value type of the returned map.
- pf
the partial function which filters and maps the map.
- returns
a new map resulting from applying the given partial function
pf
to each element on which it is defined and collecting the results. The order of the elements is preserved.
- Definition Classes
- MapOps
- def collectFirst[B](pf: PartialFunction[(K, V), B]): Option[B]
Finds the first element of the collection for which the given partial function is defined, and applies the partial function to it.
Finds the first element of the collection for which the given partial function is defined, and applies the partial function to it.
Note: may not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- pf
the partial function
- returns
an option value containing pf applied to the first value for which it is defined, or
None
if none exists.
- Definition Classes
- IterableOnceOps
Seq("a", 1, 5L).collectFirst({ case x: Int => x*10 }) = Some(10)
Example: - def compose[R](k: PartialFunction[R, K]): PartialFunction[R, V]
Composes another partial function
k
with this partial function so that this partial function gets applied to results ofk
.Composes another partial function
k
with this partial function so that this partial function gets applied to results ofk
.Note that calling isDefinedAt on the resulting partial function may apply the first partial function and execute its side effect. It is highly recommended to call applyOrElse instead of isDefinedAt / apply for efficiency.
- R
the parameter type of the transformation function.
- k
the transformation function
- returns
a partial function with the domain of other partial function narrowed by this partial function, which maps arguments
x
tothis(k(x))
.
- Definition Classes
- PartialFunction
- def compose[A](g: (A) => K): (A) => V
Composes two instances of Function1 in a new Function1, with this function applied last.
Composes two instances of Function1 in a new Function1, with this function applied last.
- A
the type to which function
g
can be applied- g
a function A => T1
- returns
a new function
f
such thatf(x) == apply(g(x))
- Definition Classes
- Function1
- Annotations
- @unspecialized()
- def concat[V2 >: V](suffix: IterableOnce[(K, V2)]): Map[K, V2]
Returns a new map containing the elements from the left hand operand followed by the elements from the right hand operand.
Returns a new map containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the map is the most specific superclass encompassing the element types of the two operands.
- suffix
the traversable to append.
- returns
a new map which contains all elements of this map followed by all elements of
suffix
.
- Definition Classes
- MapOps
- def concat[B >: (K, V)](suffix: IterableOnce[B]): Iterable[B]
Returns a new iterable collection containing the elements from the left hand operand followed by the elements from the right hand operand.
Returns a new iterable collection containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the iterable collection is the most specific superclass encompassing the element types of the two operands.
- B
the element type of the returned collection.
- suffix
the traversable to append.
- returns
a new iterable collection which contains all elements of this iterable collection followed by all elements of
suffix
.
- Definition Classes
- IterableOps
- def contains(key: K): Boolean
Tests whether this map contains a binding for a key.
- def copyToArray[B >: (K, V)](xs: Array[B], start: Int, len: Int): Int
Copy elements to an array, returning the number of elements written.
Copy elements to an array, returning the number of elements written.
Fills the given array
xs
starting at indexstart
with at mostlen
elements of this collection.Copying will stop once either all the elements of this collection have been copied, or the end of the array is reached, or
len
elements have been copied.- B
the type of the elements of the array.
- xs
the array to fill.
- start
the starting index of xs.
- len
the maximal number of elements to copy.
- returns
the number of elements written to the array
- Definition Classes
- IterableOnceOps
- Note
Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change. Note: will not terminate for infinite-sized collections.
- def copyToArray[B >: (K, V)](xs: Array[B], start: Int): Int
Copy elements to an array, returning the number of elements written.
Copy elements to an array, returning the number of elements written.
Fills the given array
xs
starting at indexstart
with values of this collection.Copying will stop once either all the elements of this collection have been copied, or the end of the array is reached.
- B
the type of the elements of the array.
- xs
the array to fill.
- start
the starting index of xs.
- returns
the number of elements written to the array Note: will not terminate for infinite-sized collections.
- Definition Classes
- IterableOnceOps
- def copyToArray[B >: (K, V)](xs: Array[B]): Int
Copy elements to an array, returning the number of elements written.
Copy elements to an array, returning the number of elements written.
Fills the given array
xs
starting at indexstart
with values of this collection.Copying will stop once either all the elements of this collection have been copied, or the end of the array is reached.
- B
the type of the elements of the array.
- xs
the array to fill.
- returns
the number of elements written to the array Note: will not terminate for infinite-sized collections.
- Definition Classes
- IterableOnceOps
- def corresponds[B](that: IterableOnce[B])(p: ((K, V), B) => Boolean): Boolean
Tests whether every element of this collection's iterator relates to the corresponding element of another collection by satisfying a test predicate.
Tests whether every element of this collection's iterator relates to the corresponding element of another collection by satisfying a test predicate.
Note: will not terminate for infinite-sized collections.
- B
the type of the elements of
that
- that
the other collection
- p
the test predicate, which relates elements from both collections
- returns
true
if both collections have the same length andp(x, y)
istrue
for all corresponding elementsx
of this iterator andy
ofthat
, otherwisefalse
- Definition Classes
- IterableOnceOps
- def count(p: ((K, V)) => Boolean): Int
Counts the number of elements in the collection which satisfy a predicate.
Counts the number of elements in the collection which satisfy a predicate.
Note: will not terminate for infinite-sized collections.
- p
the predicate used to test elements.
- returns
the number of elements satisfying the predicate
p
.
- Definition Classes
- IterableOnceOps
- def default(key: K): V
Defines the default value computation for the map, returned when a key is not found The method implemented here throws an exception, but it might be overridden in subclasses.
Defines the default value computation for the map, returned when a key is not found The method implemented here throws an exception, but it might be overridden in subclasses.
- key
the given key value for which a binding is missing.
- def drop(n: Int): Map[K, V]
Selects all elements except first n ones.
Selects all elements except first n ones.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- n
the number of elements to drop from this iterable collection.
- returns
a iterable collection consisting of all elements of this iterable collection except the first
n
ones, or else the empty iterable collection, if this iterable collection has less thann
elements. Ifn
is negative, don't drop any elements.
- Definition Classes
- IterableOps → IterableOnceOps
- def dropRight(n: Int): Map[K, V]
The rest of the collection without its
n
last elements.The rest of the collection without its
n
last elements. For linear, immutable collections this should avoid making a copy.Note: Even when applied to a view or a lazy collection it will always force the elements.
- n
the number of elements to drop from this iterable collection.
- returns
a iterable collection consisting of all elements of this iterable collection except the last
n
ones, or else the empty iterable collection, if this iterable collection has less thann
elements. Ifn
is negative, don't drop any elements.
- Definition Classes
- StrictOptimizedIterableOps → IterableOps
- def dropWhile(p: ((K, V)) => Boolean): Map[K, V]
Drops longest prefix of elements that satisfy a predicate.
Drops longest prefix of elements that satisfy a predicate.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- p
The predicate used to test elements.
- returns
the longest suffix of this iterable collection whose first element does not satisfy the predicate
p
.
- Definition Classes
- IterableOps → IterableOnceOps
- def elementWise: ElementWiseExtractor[K, V]
Returns an extractor object with a
unapplySeq
method, which extracts each element of a sequence data.Returns an extractor object with a
unapplySeq
method, which extracts each element of a sequence data.- Definition Classes
- PartialFunction
val firstChar: String => Option[Char] = _.headOption Seq("foo", "bar", "baz") match { case firstChar.unlift.elementWise(c0, c1, c2) => println(s"$c0, $c1, $c2") // Output: f, b, b }
Example: - def empty: Map[K, V]
The empty iterable of the same type as this iterable
The empty iterable of the same type as this iterable
- returns
an empty iterable of type
C
.
- Definition Classes
- MapFactoryDefaults → IterableOps
- def equals(o: Any): Boolean
The universal equality method defined in
AnyRef
. - def exists(p: ((K, V)) => Boolean): Boolean
Tests whether a predicate holds for at least one element of this immutable map.
Tests whether a predicate holds for at least one element of this immutable map.
Note: may not terminate for infinite-sized collections.
- p
the predicate used to test elements.
- returns
true
if the given predicatep
is satisfied by at least one element of this immutable map, otherwisefalse
- Definition Classes
- Map4 → IterableOnceOps
- def filter(pred: ((K, V)) => Boolean): Map[K, V]
Selects all elements of this iterable collection which satisfy a predicate.
Selects all elements of this iterable collection which satisfy a predicate.
- returns
a new iterator consisting of all elements of this iterable collection that satisfy the given predicate
p
. The order of the elements is preserved.
- Definition Classes
- StrictOptimizedIterableOps → IterableOps → IterableOnceOps
- def filterNot(pred: ((K, V)) => Boolean): Map[K, V]
Selects all elements of this iterable collection which do not satisfy a predicate.
Selects all elements of this iterable collection which do not satisfy a predicate.
- pred
the predicate used to test elements.
- returns
a new iterable collection consisting of all elements of this iterable collection that do not satisfy the given predicate
pred
. Their order may not be preserved.
- Definition Classes
- StrictOptimizedIterableOps → IterableOps → IterableOnceOps
- def find(p: ((K, V)) => Boolean): Option[(K, V)]
Finds the first element of the collection satisfying a predicate, if any.
Finds the first element of the collection satisfying a predicate, if any.
Note: may not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- p
the predicate used to test elements.
- returns
an option value containing the first element in the collection that satisfies
p
, orNone
if none exists.
- Definition Classes
- IterableOnceOps
- def flatMap[B](f: ((K, V)) => IterableOnce[B]): Iterable[B]
Builds a new iterable collection by applying a function to all elements of this iterable collection and using the elements of the resulting collections.
Builds a new iterable collection by applying a function to all elements of this iterable collection and using the elements of the resulting collections.
For example:
def getWords(lines: Seq[String]): Seq[String] = lines flatMap (line => line split "\\W+")
The type of the resulting collection is guided by the static type of iterable collection. This might cause unexpected results sometimes. For example:
// lettersOf will return a Seq[Char] of likely repeated letters, instead of a Set def lettersOf(words: Seq[String]) = words flatMap (word => word.toSet) // lettersOf will return a Set[Char], not a Seq def lettersOf(words: Seq[String]) = words.toSet flatMap ((word: String) => word.toSeq) // xs will be an Iterable[Int] val xs = Map("a" -> List(11,111), "b" -> List(22,222)).flatMap(_._2) // ys will be a Map[Int, Int] val ys = Map("a" -> List(1 -> 11,1 -> 111), "b" -> List(2 -> 22,2 -> 222)).flatMap(_._2)
- B
the element type of the returned collection.
- f
the function to apply to each element.
- returns
a new iterable collection resulting from applying the given collection-valued function
f
to each element of this iterable collection and concatenating the results.
- Definition Classes
- StrictOptimizedIterableOps → IterableOps → IterableOnceOps
- def flatMap[K2, V2](f: ((K, V)) => IterableOnce[(K2, V2)]): Map[K2, V2]
Builds a new map by applying a function to all elements of this map and using the elements of the resulting collections.
Builds a new map by applying a function to all elements of this map and using the elements of the resulting collections.
- f
the function to apply to each element.
- returns
a new map resulting from applying the given collection-valued function
f
to each element of this map and concatenating the results.
- Definition Classes
- MapOps
- def flatten[B](implicit toIterableOnce: ((K, V)) => IterableOnce[B]): Iterable[B]
Converts this iterable collection of traversable collections into a iterable collection formed by the elements of these traversable collections.
Converts this iterable collection of traversable collections into a iterable collection formed by the elements of these traversable collections.
The resulting collection's type will be guided by the type of iterable collection. For example:
val xs = List( Set(1, 2, 3), Set(1, 2, 3) ).flatten // xs == List(1, 2, 3, 1, 2, 3) val ys = Set( List(1, 2, 3), List(3, 2, 1) ).flatten // ys == Set(1, 2, 3)
- B
the type of the elements of each traversable collection.
- returns
a new iterable collection resulting from concatenating all element iterable collections.
- Definition Classes
- StrictOptimizedIterableOps → IterableOps → IterableOnceOps
- def fold[A1 >: (K, V)](z: A1)(op: (A1, A1) => A1): A1
Folds the elements of this collection using the specified associative binary operator.
Folds the elements of this collection using the specified associative binary operator. The default implementation in
IterableOnce
is equivalent tofoldLeft
but may be overridden for more efficient traversal orders.The order in which operations are performed on elements is unspecified and may be nondeterministic.
Note: will not terminate for infinite-sized collections.
- A1
a type parameter for the binary operator, a supertype of
A
.- z
a neutral element for the fold operation; may be added to the result an arbitrary number of times, and must not change the result (e.g.,
Nil
for list concatenation, 0 for addition, or 1 for multiplication).- op
a binary operator that must be associative.
- returns
the result of applying the fold operator
op
between all the elements andz
, orz
if this collection is empty.
- Definition Classes
- IterableOnceOps
- def foldLeft[B](z: B)(op: (B, (K, V)) => B): B
Applies a binary operator to a start value and all elements of this collection, going left to right.
Applies a binary operator to a start value and all elements of this collection, going left to right.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered or the operator is associative and commutative.
- B
the result type of the binary operator.
- z
the start value.
- op
the binary operator.
- returns
the result of inserting
op
between consecutive elements of this collection, going left to right with the start valuez
on the left:op(...op(z, x_1), x_2, ..., x_n)
where
x1, ..., xn
are the elements of this collection. Returnsz
if this collection is empty.
- Definition Classes
- IterableOnceOps
- def foldRight[B](z: B)(op: ((K, V), B) => B): B
Applies a binary operator to all elements of this collection and a start value, going right to left.
Applies a binary operator to all elements of this collection and a start value, going right to left.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered or the operator is associative and commutative.
- B
the result type of the binary operator.
- z
the start value.
- op
the binary operator.
- returns
the result of inserting
op
between consecutive elements of this collection, going right to left with the start valuez
on the right:op(x_1, op(x_2, ... op(x_n, z)...))
where
x1, ..., xn
are the elements of this collection. Returnsz
if this collection is empty.
- Definition Classes
- IterableOnceOps
- def forall(p: ((K, V)) => Boolean): Boolean
Tests whether a predicate holds for all elements of this immutable map.
Tests whether a predicate holds for all elements of this immutable map.
Note: may not terminate for infinite-sized collections.
- p
the predicate used to test elements.
- returns
true
if this immutable map is empty or the given predicatep
holds for all elements of this immutable map, otherwisefalse
.
- Definition Classes
- Map4 → IterableOnceOps
- def foreach[U](f: ((K, V)) => U): Unit
Apply
f
to each element for its side effects Note: [U] parameter needed to help scalac's type inference.Apply
f
to each element for its side effects Note: [U] parameter needed to help scalac's type inference.- Definition Classes
- Map4 → IterableOnceOps
- def foreachEntry[U](f: (K, V) => U): Unit
Apply
f
to each key/value pair for its side effects Note: [U] parameter needed to help scalac's type inference.Apply
f
to each key/value pair for its side effects Note: [U] parameter needed to help scalac's type inference.- Definition Classes
- MapOps
- def get(key: K): Option[V]
Optionally returns the value associated with a key.
- def getOrElse[V1 >: V](key: K, default: => V1): V1
Returns the value associated with a key, or a default value if the key is not contained in the map.
Returns the value associated with a key, or a default value if the key is not contained in the map.
- V1
the result type of the default computation.
- key
the key.
- default
a computation that yields a default value in case no binding for
key
is found in the map.- returns
the value associated with
key
if it exists, otherwise the result of thedefault
computation.
- def groupBy[K](f: ((K, V)) => K): Map[K, Map[K, V]]
Partitions this iterable collection into a map of iterable collections according to some discriminator function.
Partitions this iterable collection into a map of iterable collections according to some discriminator function.
Note: Even when applied to a view or a lazy collection it will always force the elements.
- K
the type of keys returned by the discriminator function.
- f
the discriminator function.
- returns
A map from keys to iterable collections such that the following invariant holds:
(xs groupBy f)(k) = xs filter (x => f(x) == k)
That is, every key
k
is bound to a iterable collection of those elementsx
for whichf(x)
equalsk
.
- Definition Classes
- IterableOps
- def groupMap[K, B](key: ((K, V)) => K)(f: ((K, V)) => B): Map[K, Iterable[B]]
Partitions this iterable collection into a map of iterable collections according to a discriminator function
key
.Partitions this iterable collection into a map of iterable collections according to a discriminator function
key
. Each element in a group is transformed into a value of typeB
using thevalue
function.It is equivalent to
groupBy(key).mapValues(_.map(f))
, but more efficient.case class User(name: String, age: Int) def namesByAge(users: Seq[User]): Map[Int, Seq[String]] = users.groupMap(_.age)(_.name)
Note: Even when applied to a view or a lazy collection it will always force the elements.
- K
the type of keys returned by the discriminator function
- B
the type of values returned by the transformation function
- key
the discriminator function
- f
the element transformation function
- Definition Classes
- IterableOps
- def groupMapReduce[K, B](key: ((K, V)) => K)(f: ((K, V)) => B)(reduce: (B, B) => B): Map[K, B]
Partitions this iterable collection into a map according to a discriminator function
key
.Partitions this iterable collection into a map according to a discriminator function
key
. All the values that have the same discriminator are then transformed by thevalue
function and then reduced into a single value with thereduce
function.It is equivalent to
groupBy(key).mapValues(_.map(f).reduce(reduce))
, but more efficient.def occurrences[A](as: Seq[A]): Map[A, Int] = as.groupMapReduce(identity)(_ => 1)(_ + _)
Note: Even when applied to a view or a lazy collection it will always force the elements.
- Definition Classes
- IterableOps
- def grouped(size: Int): Iterator[Map[K, V]]
Partitions elements in fixed size iterable collections.
Partitions elements in fixed size iterable collections.
- size
the number of elements per group
- returns
An iterator producing iterable collections of size
size
, except the last will be less than sizesize
if the elements don't divide evenly.
- Definition Classes
- IterableOps
- See also
scala.collection.Iterator, method
grouped
- def hashCode(): Int
The hashCode method for reference types.
- def head: (K, V)
Selects the first element of this iterable collection.
Selects the first element of this iterable collection.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- returns
the first element of this iterable collection.
- Definition Classes
- IterableOps
- Exceptions thrown
NoSuchElementException
if the iterable collection is empty.
- def headOption: Option[(K, V)]
Optionally selects the first element.
Optionally selects the first element.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- returns
the first element of this iterable collection if it is nonempty,
None
if it is empty.
- Definition Classes
- IterableOps
- def init: Map[K, V]
The initial part of the collection without its last element.
The initial part of the collection without its last element.
Note: Even when applied to a view or a lazy collection it will always force the elements.
- Definition Classes
- IterableOps
- def inits: Iterator[Map[K, V]]
Iterates over the inits of this iterable collection.
Iterates over the inits of this iterable collection. The first value will be this iterable collection and the final one will be an empty iterable collection, with the intervening values the results of successive applications of
init
.Note: Even when applied to a view or a lazy collection it will always force the elements.
- returns
an iterator over all the inits of this iterable collection
- Definition Classes
- IterableOps
List(1,2,3).inits = Iterator(List(1,2,3), List(1,2), List(1), Nil)
Example: - def isDefinedAt(key: K): Boolean
Tests whether this map contains a binding for a key.
Tests whether this map contains a binding for a key. This method, which implements an abstract method of trait
PartialFunction
, is equivalent tocontains
.- key
the key
- returns
true
if there is a binding forkey
in this map,false
otherwise.
- Definition Classes
- MapOps → PartialFunction
- def isEmpty: Boolean
Tests whether the immutable map is empty.
Tests whether the immutable map is empty.
Note: Implementations in subclasses that are not repeatedly traversable must take care not to consume any elements when
isEmpty
is called.- returns
true
if the immutable map contains no elements,false
otherwise.
- Definition Classes
- Map4 → IterableOnceOps
- def isTraversableAgain: Boolean
Tests whether this iterable collection can be repeatedly traversed.
Tests whether this iterable collection can be repeatedly traversed. Always true for Iterables and false for Iterators unless overridden.
- returns
true
if it is repeatedly traversable,false
otherwise.
- Definition Classes
- IterableOps → IterableOnceOps
- def iterableFactory: IterableFactory[Iterable]
The companion object of this immutable collection, providing various factory methods.
The companion object of this immutable collection, providing various factory methods.
- Definition Classes
- Iterable → Iterable → IterableOps
- Note
When implementing a custom collection type and refining
CC
to the new type, this method needs to be overridden to return a factory for the new type (the compiler will issue an error otherwise).
- def iterator: Iterator[(K, V)]
Iterator can be used only once
Iterator can be used only once
- Definition Classes
- Map4 → IterableOnce
- def keySet: Set[K]
Collects all keys of this map in a set.
- def keyStepper[S <: Stepper[_]](implicit shape: StepperShape[K, S]): S
Returns a Stepper for the keys of this map.
- def keys: collection.Iterable[K]
Collects all keys of this map in an iterable collection.
Collects all keys of this map in an iterable collection.
- returns
the keys of this map as an iterable.
- Definition Classes
- MapOps
- def keysIterator: Iterator[K]
Creates an iterator for all keys.
- def knownSize: Int
- returns
The number of elements in this immutable map, if it can be cheaply computed, -1 otherwise. Cheaply usually means: Not requiring a collection traversal.
- Definition Classes
- Map4 → IterableOnce
- def last: (K, V)
Selects the last element.
Selects the last element.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- returns
The last element of this iterable collection.
- Definition Classes
- IterableOps
- Exceptions thrown
NoSuchElementException
If the iterable collection is empty.
- def lastOption: Option[(K, V)]
Optionally selects the last element.
Optionally selects the last element.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- returns
the last element of this iterable collection$ if it is nonempty,
None
if it is empty.
- Definition Classes
- IterableOps
- def lazyZip[B](that: collection.Iterable[B]): LazyZip2[(K, V), B, Map4.this.type]
Analogous to
zip
except that the elements in each collection are not consumed until a strict operation is invoked on the returnedLazyZip2
decorator.Analogous to
zip
except that the elements in each collection are not consumed until a strict operation is invoked on the returnedLazyZip2
decorator.Calls to
lazyZip
can be chained to support higher arities (up to 4) without incurring the expense of constructing and deconstructing intermediary tuples.val xs = List(1, 2, 3) val res = (xs lazyZip xs lazyZip xs lazyZip xs).map((a, b, c, d) => a + b + c + d) // res == List(4, 8, 12)
- B
the type of the second element in each eventual pair
- that
the iterable providing the second element of each eventual pair
- returns
a decorator
LazyZip2
that allows strict operations to be performed on the lazily evaluated pairs or chained calls tolazyZip
. Implicit conversion toIterable[(A, B)]
is also supported.
- Definition Classes
- Iterable
- def lift: (K) => Option[V]
Turns this partial function into a plain function returning an
Option
result.Turns this partial function into a plain function returning an
Option
result.- returns
a function that takes an argument
x
toSome(this(x))
ifthis
is defined forx
, and toNone
otherwise.
- Definition Classes
- PartialFunction
- See also
Function.unlift
- def map[B](f: ((K, V)) => B): Iterable[B]
Builds a new iterable collection by applying a function to all elements of this iterable collection.
Builds a new iterable collection by applying a function to all elements of this iterable collection.
- B
the element type of the returned iterable collection.
- f
the function to apply to each element.
- returns
a new iterable collection resulting from applying the given function
f
to each element of this iterable collection and collecting the results.
- Definition Classes
- StrictOptimizedIterableOps → IterableOps → IterableOnceOps
- def map[K2, V2](f: ((K, V)) => (K2, V2)): Map[K2, V2]
Builds a new map by applying a function to all elements of this map.
Builds a new map by applying a function to all elements of this map.
- f
the function to apply to each element.
- returns
a new map resulting from applying the given function
f
to each element of this map and collecting the results.
- Definition Classes
- MapOps
- def mapFactory: MapFactory[Map]
The companion object of this map, providing various factory methods.
The companion object of this map, providing various factory methods.
- def max[B >: (K, V)](implicit ord: math.Ordering[B]): (K, V)
Finds the largest element.
Finds the largest element.
Note: will not terminate for infinite-sized collections.
- B
The type over which the ordering is defined.
- ord
An ordering to be used for comparing elements.
- returns
the largest element of this collection with respect to the ordering
ord
.
- Definition Classes
- IterableOnceOps
- Exceptions thrown
UnsupportedOperationException
if this collection is empty.
- def maxBy[B](f: ((K, V)) => B)(implicit cmp: math.Ordering[B]): (K, V)
Finds the first element which yields the largest value measured by function f.
Finds the first element which yields the largest value measured by function f.
Note: will not terminate for infinite-sized collections.
- B
The result type of the function f.
- f
The measuring function.
- cmp
An ordering to be used for comparing elements.
- returns
the first element of this collection with the largest value measured by function f with respect to the ordering
cmp
.
- Definition Classes
- IterableOnceOps
- Exceptions thrown
UnsupportedOperationException
if this collection is empty.
- def maxByOption[B](f: ((K, V)) => B)(implicit cmp: math.Ordering[B]): Option[(K, V)]
Finds the first element which yields the largest value measured by function f.
Finds the first element which yields the largest value measured by function f.
Note: will not terminate for infinite-sized collections.
- B
The result type of the function f.
- f
The measuring function.
- cmp
An ordering to be used for comparing elements.
- returns
an option value containing the first element of this collection with the largest value measured by function f with respect to the ordering
cmp
.
- Definition Classes
- IterableOnceOps
- def maxOption[B >: (K, V)](implicit ord: math.Ordering[B]): Option[(K, V)]
Finds the largest element.
Finds the largest element.
Note: will not terminate for infinite-sized collections.
- B
The type over which the ordering is defined.
- ord
An ordering to be used for comparing elements.
- returns
an option value containing the largest element of this collection with respect to the ordering
ord
.
- Definition Classes
- IterableOnceOps
- def min[B >: (K, V)](implicit ord: math.Ordering[B]): (K, V)
Finds the smallest element.
Finds the smallest element.
Note: will not terminate for infinite-sized collections.
- B
The type over which the ordering is defined.
- ord
An ordering to be used for comparing elements.
- returns
the smallest element of this collection with respect to the ordering
ord
.
- Definition Classes
- IterableOnceOps
- Exceptions thrown
UnsupportedOperationException
if this collection is empty.
- def minBy[B](f: ((K, V)) => B)(implicit cmp: math.Ordering[B]): (K, V)
Finds the first element which yields the smallest value measured by function f.
Finds the first element which yields the smallest value measured by function f.
Note: will not terminate for infinite-sized collections.
- B
The result type of the function f.
- f
The measuring function.
- cmp
An ordering to be used for comparing elements.
- returns
the first element of this collection with the smallest value measured by function f with respect to the ordering
cmp
.
- Definition Classes
- IterableOnceOps
- Exceptions thrown
UnsupportedOperationException
if this collection is empty.
- def minByOption[B](f: ((K, V)) => B)(implicit cmp: math.Ordering[B]): Option[(K, V)]
Finds the first element which yields the smallest value measured by function f.
Finds the first element which yields the smallest value measured by function f.
Note: will not terminate for infinite-sized collections.
- B
The result type of the function f.
- f
The measuring function.
- cmp
An ordering to be used for comparing elements.
- returns
an option value containing the first element of this collection with the smallest value measured by function f with respect to the ordering
cmp
.
- Definition Classes
- IterableOnceOps
- def minOption[B >: (K, V)](implicit ord: math.Ordering[B]): Option[(K, V)]
Finds the smallest element.
Finds the smallest element.
Note: will not terminate for infinite-sized collections.
- B
The type over which the ordering is defined.
- ord
An ordering to be used for comparing elements.
- returns
an option value containing the smallest element of this collection with respect to the ordering
ord
.
- Definition Classes
- IterableOnceOps
- final def mkString: String
Displays all elements of this collection in a string.
Displays all elements of this collection in a string.
Delegates to addString, which can be overridden.
- returns
a string representation of this collection. In the resulting string the string representations (w.r.t. the method
toString
) of all elements of this collection follow each other without any separator string.
- Definition Classes
- IterableOnceOps
- Annotations
- @inline()
- final def mkString(sep: String): String
Displays all elements of this collection in a string using a separator string.
Displays all elements of this collection in a string using a separator string.
Delegates to addString, which can be overridden.
- sep
the separator string.
- returns
a string representation of this collection. In the resulting string the string representations (w.r.t. the method
toString
) of all elements of this collection are separated by the stringsep
.
- Definition Classes
- IterableOnceOps
- Annotations
- @inline()
List(1, 2, 3).mkString("|") = "1|2|3"
Example: - final def mkString(start: String, sep: String, end: String): String
Displays all elements of this collection in a string using start, end, and separator strings.
Displays all elements of this collection in a string using start, end, and separator strings.
Delegates to addString, which can be overridden.
- start
the starting string.
- sep
the separator string.
- end
the ending string.
- returns
a string representation of this collection. The resulting string begins with the string
start
and ends with the stringend
. Inside, the string representations (w.r.t. the methodtoString
) of all elements of this collection are separated by the stringsep
.
- Definition Classes
- IterableOnceOps
List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"
Example: - def nonEmpty: Boolean
Tests whether the collection is not empty.
Tests whether the collection is not empty.
- returns
true
if the collection contains at least one element,false
otherwise.
- Definition Classes
- IterableOnceOps
- Annotations
- @deprecatedOverriding(message = "nonEmpty is defined as !isEmpty; override isEmpty instead", since = "2.13.0")
- def orElse[A1 <: K, B1 >: V](that: PartialFunction[A1, B1]): PartialFunction[A1, B1]
Composes this partial function with a fallback partial function which gets applied where this partial function is not defined.
Composes this partial function with a fallback partial function which gets applied where this partial function is not defined.
- A1
the argument type of the fallback function
- B1
the result type of the fallback function
- that
the fallback function
- returns
a partial function which has as domain the union of the domains of this partial function and
that
. The resulting partial function takesx
tothis(x)
wherethis
is defined, and tothat(x)
where it is not.
- Definition Classes
- PartialFunction
- def partition(p: ((K, V)) => Boolean): (Map[K, V], Map[K, V])
A pair of, first, all elements that satisfy predicate
p
and, second, all elements that do not.A pair of, first, all elements that satisfy predicate
p
and, second, all elements that do not. Interesting because it splits a collection in two.The default implementation provided here needs to traverse the collection twice. Strict collections have an overridden version of
partition
inStrictOptimizedIterableOps
, which requires only a single traversal.- Definition Classes
- StrictOptimizedIterableOps → IterableOps
- def partitionMap[A1, A2](f: ((K, V)) => Either[A1, A2]): (Iterable[A1], Iterable[A2])
Applies a function
f
to each element of the iterable collection and returns a pair of iterable collections: the first one made of those values returned byf
that were wrapped in scala.util.Left, and the second one made of those wrapped in scala.util.Right.Applies a function
f
to each element of the iterable collection and returns a pair of iterable collections: the first one made of those values returned byf
that were wrapped in scala.util.Left, and the second one made of those wrapped in scala.util.Right.Example:
val xs = Iterable(1, "one", 2, "two", 3, "three") partitionMap { case i: Int => Left(i) case s: String => Right(s) } // xs == (Iterable(1, 2, 3), // Iterable(one, two, three))
- A1
the element type of the first resulting collection
- A2
the element type of the second resulting collection
- f
the 'split function' mapping the elements of this iterable collection to an scala.util.Either
- returns
a pair of iterable collections: the first one made of those values returned by
f
that were wrapped in scala.util.Left, and the second one made of those wrapped in scala.util.Right.
- Definition Classes
- StrictOptimizedIterableOps → IterableOps
- def product[B >: (K, V)](implicit num: math.Numeric[B]): B
Multiplies up the elements of this collection.
Multiplies up the elements of this collection.
Note: will not terminate for infinite-sized collections.
- B
the result type of the
*
operator.- num
an implicit parameter defining a set of numeric operations which includes the
*
operator to be used in forming the product.- returns
the product of all elements of this collection with respect to the
*
operator innum
.
- Definition Classes
- IterableOnceOps
- def reduce[B >: (K, V)](op: (B, B) => B): B
Reduces the elements of this collection using the specified associative binary operator.
Reduces the elements of this collection using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
- B
A type parameter for the binary operator, a supertype of
A
.- op
A binary operator that must be associative.
- returns
The result of applying reduce operator
op
between all the elements if the collection is nonempty.
- Definition Classes
- IterableOnceOps
- Exceptions thrown
UnsupportedOperationException
if this collection is empty.
- def reduceLeft[B >: (K, V)](op: (B, (K, V)) => B): B
Applies a binary operator to all elements of this collection, going left to right.
Applies a binary operator to all elements of this collection, going left to right.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered or the operator is associative and commutative.
- B
the result type of the binary operator.
- op
the binary operator.
- returns
the result of inserting
op
between consecutive elements of this collection, going left to right:op( op( ... op(x_1, x_2) ..., x_{n-1}), x_n)
where
x1, ..., xn
are the elements of this collection.
- Definition Classes
- IterableOnceOps
- Exceptions thrown
UnsupportedOperationException
if this collection is empty.
- def reduceLeftOption[B >: (K, V)](op: (B, (K, V)) => B): Option[B]
Optionally applies a binary operator to all elements of this collection, going left to right.
Optionally applies a binary operator to all elements of this collection, going left to right.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered or the operator is associative and commutative.
- B
the result type of the binary operator.
- op
the binary operator.
- returns
an option value containing the result of
reduceLeft(op)
if this collection is nonempty,None
otherwise.
- Definition Classes
- IterableOnceOps
- def reduceOption[B >: (K, V)](op: (B, B) => B): Option[B]
Reduces the elements of this collection, if any, using the specified associative binary operator.
Reduces the elements of this collection, if any, using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
- B
A type parameter for the binary operator, a supertype of
A
.- op
A binary operator that must be associative.
- returns
An option value containing result of applying reduce operator
op
between all the elements if the collection is nonempty, andNone
otherwise.
- Definition Classes
- IterableOnceOps
- def reduceRight[B >: (K, V)](op: ((K, V), B) => B): B
Applies a binary operator to all elements of this collection, going right to left.
Applies a binary operator to all elements of this collection, going right to left.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered or the operator is associative and commutative.
- B
the result type of the binary operator.
- op
the binary operator.
- returns
the result of inserting
op
between consecutive elements of this collection, going right to left:op(x_1, op(x_2, ..., op(x_{n-1}, x_n)...))
where
x1, ..., xn
are the elements of this collection.
- Definition Classes
- IterableOnceOps
- Exceptions thrown
UnsupportedOperationException
if this collection is empty.
- def reduceRightOption[B >: (K, V)](op: ((K, V), B) => B): Option[B]
Optionally applies a binary operator to all elements of this collection, going right to left.
Optionally applies a binary operator to all elements of this collection, going right to left.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered or the operator is associative and commutative.
- B
the result type of the binary operator.
- op
the binary operator.
- returns
an option value containing the result of
reduceRight(op)
if this collection is nonempty,None
otherwise.
- Definition Classes
- IterableOnceOps
- def removed(key: K): Map[K, V]
Removes a key from this map, returning a new map.
- def removedAll(keys: IterableOnce[K]): Map[K, V]
Creates a new immutable map from this immutable map by removing all elements of another collection.
Creates a new immutable map from this immutable map by removing all elements of another collection.
Note: Even when applied to a view or a lazy collection it will always force the elements.
- keys
the collection containing the removed elements.
- returns
a new immutable map that contains all elements of the current immutable map except one less occurrence of each of the elements of
elems
.
- Definition Classes
- MapOps
- def runWith[U](action: (V) => U): (K) => Boolean
Composes this partial function with an action function which gets applied to results of this partial function.
Composes this partial function with an action function which gets applied to results of this partial function. The action function is invoked only for its side effects; its result is ignored.
Note that expression
pf.runWith(action)(x)
is equivalent toif(pf isDefinedAt x) { action(pf(x)); true } else false
except that
runWith
is implemented viaapplyOrElse
and thus potentially more efficient. UsingrunWith
avoids double evaluation of pattern matchers and guards for partial function literals.- action
the action function
- returns
a function which maps arguments
x
toisDefinedAt(x)
. The resulting function runsaction(this(x))
wherethis
is defined.
- Definition Classes
- PartialFunction
- See also
applyOrElse
.
- def scan[B >: (K, V)](z: B)(op: (B, B) => B): Iterable[B]
Computes a prefix scan of the elements of the collection.
Computes a prefix scan of the elements of the collection.
Note: The neutral element
z
may be applied more than once.- B
element type of the resulting collection
- z
neutral element for the operator
op
- op
the associative operator for the scan
- returns
a new iterable collection containing the prefix scan of the elements in this iterable collection
- Definition Classes
- IterableOps
- def scanLeft[B](z: B)(op: (B, (K, V)) => B): Iterable[B]
Produces a iterable collection containing cumulative results of applying the operator going left to right, including the initial value.
Produces a iterable collection containing cumulative results of applying the operator going left to right, including the initial value.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- B
the type of the elements in the resulting collection
- z
the initial value
- op
the binary operator applied to the intermediate result and the element
- returns
collection with intermediate results
- Definition Classes
- StrictOptimizedIterableOps → IterableOps → IterableOnceOps
- def scanRight[B](z: B)(op: ((K, V), B) => B): Iterable[B]
Produces a collection containing cumulative results of applying the operator going right to left.
Produces a collection containing cumulative results of applying the operator going right to left. The head of the collection is the last cumulative result.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered.
Note: Even when applied to a view or a lazy collection it will always force the elements.
Example:
List(1, 2, 3, 4).scanRight(0)(_ + _) == List(10, 9, 7, 4, 0)
- B
the type of the elements in the resulting collection
- z
the initial value
- op
the binary operator applied to the intermediate result and the element
- returns
collection with intermediate results
- Definition Classes
- IterableOps
- def size: Int
The size of this immutable map.
The size of this immutable map.
Note: will not terminate for infinite-sized collections.
- returns
the number of elements in this immutable map.
- Definition Classes
- Map4 → IterableOnceOps
- def sizeCompare(that: collection.Iterable[_]): Int
Compares the size of this iterable collection to the size of another
Iterable
.Compares the size of this iterable collection to the size of another
Iterable
.- that
the
Iterable
whose size is compared with this iterable collection's size.- returns
A value
x
wherex < 0 if this.size < that.size x == 0 if this.size == that.size x > 0 if this.size > that.size
The method as implemented here does not call
size
directly; its running time isO(this.size min that.size)
instead ofO(this.size + that.size)
. The method should be overridden if computingsize
is cheap andknownSize
returns-1
.
- Definition Classes
- IterableOps
- def sizeCompare(otherSize: Int): Int
Compares the size of this iterable collection to a test value.
Compares the size of this iterable collection to a test value.
- otherSize
the test value that gets compared with the size.
- returns
A value
x
wherex < 0 if this.size < otherSize x == 0 if this.size == otherSize x > 0 if this.size > otherSize
The method as implemented here does not call
size
directly; its running time isO(size min otherSize)
instead ofO(size)
. The method should be overridden if computingsize
is cheap andknownSize
returns-1
.
- Definition Classes
- IterableOps
- See also
- final def sizeIs: SizeCompareOps
Returns a value class containing operations for comparing the size of this iterable collection to a test value.
Returns a value class containing operations for comparing the size of this iterable collection to a test value.
These operations are implemented in terms of
sizeCompare(Int)
, and allow the following more readable usages:this.sizeIs < size // this.sizeCompare(size) < 0 this.sizeIs <= size // this.sizeCompare(size) <= 0 this.sizeIs == size // this.sizeCompare(size) == 0 this.sizeIs != size // this.sizeCompare(size) != 0 this.sizeIs >= size // this.sizeCompare(size) >= 0 this.sizeIs > size // this.sizeCompare(size) > 0
- Definition Classes
- IterableOps
- Annotations
- @inline()
- def slice(from: Int, until: Int): Map[K, V]
Selects an interval of elements.
Selects an interval of elements. The returned iterable collection is made up of all elements
x
which satisfy the invariant:from <= indexOf(x) < until
Note: might return different results for different runs, unless the underlying collection type is ordered.
- from
the lowest index to include from this iterable collection.
- until
the lowest index to EXCLUDE from this iterable collection.
- returns
a iterable collection containing the elements greater than or equal to index
from
extending up to (but not including) indexuntil
of this iterable collection.
- Definition Classes
- IterableOps → IterableOnceOps
- def sliding(size: Int, step: Int): Iterator[Map[K, V]]
Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.)
Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.)
The returned iterator will be empty when called on an empty collection. The last element the iterator produces may be smaller than the window size when the original collection isn't exhausted by the window before it and its last element isn't skipped by the step before it.
- size
the number of elements per group
- step
the distance between the first elements of successive groups
- returns
An iterator producing iterable collections of size
size
, except the last element (which may be the only element) will be smaller if there are fewer thansize
elements remaining to be grouped.
- Definition Classes
- IterableOps
List(1, 2, 3, 4, 5).sliding(2, 2) = Iterator(List(1, 2), List(3, 4), List(5))
, List(1, 2, 3, 4, 5, 6).sliding(2, 3) = Iterator(List(1, 2), List(4, 5))
- See also
scala.collection.Iterator, method
sliding
Examples: - def sliding(size: Int): Iterator[Map[K, V]]
Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in
grouped
.)Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in
grouped
.)An empty collection returns an empty iterator, and a non-empty collection containing fewer elements than the window size returns an iterator that will produce the original collection as its only element.
- size
the number of elements per group
- returns
An iterator producing iterable collections of size
size
, except for a non-empty collection with less thansize
elements, which returns an iterator that produces the source collection itself as its only element.
- Definition Classes
- IterableOps
List().sliding(2) = empty iterator
, List(1).sliding(2) = Iterator(List(1))
, List(1, 2).sliding(2) = Iterator(List(1, 2))
, List(1, 2, 3).sliding(2) = Iterator(List(1, 2), List(2, 3))
- See also
scala.collection.Iterator, method
sliding
Examples: - def span(p: ((K, V)) => Boolean): (Map[K, V], Map[K, V])
Splits this iterable collection into a prefix/suffix pair according to a predicate.
Splits this iterable collection into a prefix/suffix pair according to a predicate.
Note:
c span p
is equivalent to (but possibly more efficient than)(c takeWhile p, c dropWhile p)
, provided the evaluation of the predicatep
does not cause any side-effects.Note: might return different results for different runs, unless the underlying collection type is ordered.
- p
the test predicate
- returns
a pair consisting of the longest prefix of this iterable collection whose elements all satisfy
p
, and the rest of this iterable collection.
- Definition Classes
- StrictOptimizedIterableOps → IterableOps → IterableOnceOps
- def splitAt(n: Int): (Map[K, V], Map[K, V])
Splits this iterable collection into a prefix/suffix pair at a given position.
Splits this iterable collection into a prefix/suffix pair at a given position.
Note:
c splitAt n
is equivalent to (but possibly more efficient than)(c take n, c drop n)
.Note: might return different results for different runs, unless the underlying collection type is ordered.
- n
the position at which to split.
- returns
a pair of iterable collections consisting of the first
n
elements of this iterable collection, and the other elements.
- Definition Classes
- IterableOps → IterableOnceOps
- def stepper[S <: Stepper[_]](implicit shape: StepperShape[(K, V), S]): S
Returns a scala.collection.Stepper for the elements of this collection.
Returns a scala.collection.Stepper for the elements of this collection.
The Stepper enables creating a Java stream to operate on the collection, see scala.jdk.StreamConverters. For collections holding primitive values, the Stepper can be used as an iterator which doesn't box the elements.
The implicit scala.collection.StepperShape parameter defines the resulting Stepper type according to the element type of this collection.
- For collections of
Int
,Short
,Byte
orChar
, an scala.collection.IntStepper is returned - For collections of
Double
orFloat
, a scala.collection.DoubleStepper is returned - For collections of
Long
a scala.collection.LongStepper is returned - For any other element type, an scala.collection.AnyStepper is returned
Note that this method is overridden in subclasses and the return type is refined to
S with EfficientSplit
, for example scala.collection.IndexedSeqOps.stepper. For Steppers marked with scala.collection.Stepper.EfficientSplit, the converters in scala.jdk.StreamConverters allow creating parallel streams, whereas bare Steppers can be converted only to sequential streams.- Definition Classes
- IterableOnce
- For collections of
- def sum[B >: (K, V)](implicit num: math.Numeric[B]): B
Sums up the elements of this collection.
Sums up the elements of this collection.
Note: will not terminate for infinite-sized collections.
- B
the result type of the
+
operator.- num
an implicit parameter defining a set of numeric operations which includes the
+
operator to be used in forming the sum.- returns
the sum of all elements of this collection with respect to the
+
operator innum
.
- Definition Classes
- IterableOnceOps
- def tail: Map[K, V]
The rest of the collection without its first element.
The rest of the collection without its first element.
- Definition Classes
- IterableOps
- def tails: Iterator[Map[K, V]]
Iterates over the tails of this iterable collection.
Iterates over the tails of this iterable collection. The first value will be this iterable collection and the final one will be an empty iterable collection, with the intervening values the results of successive applications of
tail
.- returns
an iterator over all the tails of this iterable collection
- Definition Classes
- IterableOps
List(1,2,3).tails = Iterator(List(1,2,3), List(2,3), List(3), Nil)
Example: - def take(n: Int): Map[K, V]
Selects the first n elements.
Selects the first n elements.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- n
the number of elements to take from this iterable collection.
- returns
a iterable collection consisting only of the first
n
elements of this iterable collection, or else the whole iterable collection, if it has less thann
elements. Ifn
is negative, returns an empty iterable collection.
- Definition Classes
- IterableOps → IterableOnceOps
- def takeRight(n: Int): Map[K, V]
A collection containing the last
n
elements of this collection.A collection containing the last
n
elements of this collection.Note: Even when applied to a view or a lazy collection it will always force the elements.
- n
the number of elements to take from this iterable collection.
- returns
a iterable collection consisting only of the last
n
elements of this iterable collection, or else the whole iterable collection, if it has less thann
elements. Ifn
is negative, returns an empty iterable collection.
- Definition Classes
- StrictOptimizedIterableOps → IterableOps
- def takeWhile(p: ((K, V)) => Boolean): Map[K, V]
Takes longest prefix of elements that satisfy a predicate.
Takes longest prefix of elements that satisfy a predicate.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- p
The predicate used to test elements.
- returns
the longest prefix of this iterable collection whose elements all satisfy the predicate
p
.
- Definition Classes
- IterableOps → IterableOnceOps
- def tapEach[U](f: ((K, V)) => U): Map[K, V]
Applies a side-effecting function to each element in this collection.
Applies a side-effecting function to each element in this collection. Strict collections will apply
f
to their elements immediately, while lazy collections like Views and LazyLists will only applyf
on each element if and when that element is evaluated, and each time that element is evaluated.- U
the return type of f
- f
a function to apply to each element in this iterable collection
- returns
The same logical collection as this
- Definition Classes
- StrictOptimizedIterableOps → IterableOps → IterableOnceOps
- def to[C1](factory: Factory[(K, V), C1]): C1
Given a collection factory
factory
, convert this collection to the appropriate representation for the current element typeA
.Given a collection factory
factory
, convert this collection to the appropriate representation for the current element typeA
. Example uses:xs.to(List) xs.to(ArrayBuffer) xs.to(BitSet) // for xs: Iterable[Int]
- Definition Classes
- IterableOnceOps
- def toArray[B >: (K, V)](implicit arg0: ClassTag[B]): Array[B]
Convert collection to array.
Convert collection to array.
Implementation note: DO NOT call Array.from from this method.
- Definition Classes
- IterableOnceOps
- final def toBuffer[B >: (K, V)]: Buffer[B]
- Definition Classes
- IterableOnceOps
- Annotations
- @inline()
- def toIndexedSeq: IndexedSeq[(K, V)]
- Definition Classes
- IterableOnceOps
- final def toIterable: Map4.this.type
- returns
This collection as an
Iterable[A]
. No new collection will be built ifthis
is already anIterable[A]
.
- Definition Classes
- Iterable → IterableOps
- def toList: List[(K, V)]
- Definition Classes
- IterableOnceOps
- final def toMap[K2, V2](implicit ev: <:<[(K, V), (K2, V2)]): Map[K2, V2]
- Definition Classes
- Map → IterableOnceOps
- def toSeq: Seq[(K, V)]
- returns
This collection as a
Seq[A]
. This is equivalent toto(Seq)
but might be faster.
- Definition Classes
- IterableOnceOps
- def toSet[B >: (K, V)]: Set[B]
- Definition Classes
- IterableOnceOps
- def toString(): String
Creates a String representation of this object.
Creates a String representation of this object. The default representation is platform dependent. On the java platform it is the concatenation of the class name, "@", and the object's hashcode in hexadecimal.
- returns
a String representation of the object.
- def toVector: Vector[(K, V)]
- Definition Classes
- IterableOnceOps
- def transform[W](f: (K, V) => W): Map[K, W]
This function transforms all the values of mappings contained in this map with function
f
. - def transpose[B](implicit asIterable: ((K, V)) => collection.Iterable[B]): Iterable[Iterable[B]]
Transposes this iterable collection of iterable collections into a iterable collection of iterable collections.
Transposes this iterable collection of iterable collections into a iterable collection of iterable collections.
The resulting collection's type will be guided by the static type of iterable collection. For example:
val xs = List( Set(1, 2, 3), Set(4, 5, 6)).transpose // xs == List( // List(1, 4), // List(2, 5), // List(3, 6)) val ys = Vector( List(1, 2, 3), List(4, 5, 6)).transpose // ys == Vector( // Vector(1, 4), // Vector(2, 5), // Vector(3, 6))
Note: Even when applied to a view or a lazy collection it will always force the elements.
- B
the type of the elements of each iterable collection.
- asIterable
an implicit conversion which asserts that the element type of this iterable collection is an
Iterable
.- returns
a two-dimensional iterable collection of iterable collections which has as nth row the nth column of this iterable collection.
- Definition Classes
- IterableOps
- Exceptions thrown
IllegalArgumentException
if all collections in this iterable collection are not of the same size.
- def unapply(a: K): Option[V]
Tries to extract a
B
from anA
in a pattern matching expression.Tries to extract a
B
from anA
in a pattern matching expression.- Definition Classes
- PartialFunction
- def unlift: PartialFunction[K, B]
Converts an optional function to a partial function.
Converts an optional function to a partial function.
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toUnliftOps[K, B] performed by method UnliftOps in scala.Function1.This conversion will take place only if V is a subclass of Option[B] (V <: Option[B]).
- Definition Classes
- UnliftOps
Unlike Function.unlift, this UnliftOps.unlift method can be used in extractors.
val of: Int => Option[String] = { i => if (i == 2) { Some("matched by an optional function") } else { None } } util.Random.nextInt(4) match { case of.unlift(m) => // Convert an optional function to a pattern println(m) case _ => println("Not matched") }
Example: - def unzip[A1, A2](implicit asPair: ((K, V)) => (A1, A2)): (Iterable[A1], Iterable[A2])
Converts this iterable collection of pairs into two collections of the first and second half of each pair.
Converts this iterable collection of pairs into two collections of the first and second half of each pair.
val xs = Iterable( (1, "one"), (2, "two"), (3, "three")).unzip // xs == (Iterable(1, 2, 3), // Iterable(one, two, three))
- A1
the type of the first half of the element pairs
- A2
the type of the second half of the element pairs
- asPair
an implicit conversion which asserts that the element type of this iterable collection is a pair.
- returns
a pair of iterable collections, containing the first, respectively second half of each element pair of this iterable collection.
- Definition Classes
- StrictOptimizedIterableOps → IterableOps
- def unzip3[A1, A2, A3](implicit asTriple: ((K, V)) => (A1, A2, A3)): (Iterable[A1], Iterable[A2], Iterable[A3])
Converts this iterable collection of triples into three collections of the first, second, and third element of each triple.
Converts this iterable collection of triples into three collections of the first, second, and third element of each triple.
val xs = Iterable( (1, "one", '1'), (2, "two", '2'), (3, "three", '3')).unzip3 // xs == (Iterable(1, 2, 3), // Iterable(one, two, three), // Iterable(1, 2, 3))
- A1
the type of the first member of the element triples
- A2
the type of the second member of the element triples
- A3
the type of the third member of the element triples
- asTriple
an implicit conversion which asserts that the element type of this iterable collection is a triple.
- returns
a triple of iterable collections, containing the first, second, respectively third member of each element triple of this iterable collection.
- Definition Classes
- StrictOptimizedIterableOps → IterableOps
- def updated[V1 >: V](key: K, value: V1): Map[K, V1]
Creates a new map obtained by updating this map with a given key/value pair.
- def updatedWith[V1 >: V](key: K)(remappingFunction: (Option[V]) => Option[V1]): Map[K, V1]
Update a mapping for the specified key and its current optionally-mapped value (
Some
if there is current mapping,None
if not).Update a mapping for the specified key and its current optionally-mapped value (
Some
if there is current mapping,None
if not).If the remapping function returns
Some(v)
, the mapping is updated with the new valuev
. If the remapping function returnsNone
, the mapping is removed (or remains absent if initially absent). If the function itself throws an exception, the exception is rethrown, and the current mapping is left unchanged.- key
the key value
- remappingFunction
a partial function that receives current optionally-mapped value and return a new mapping
- returns
A new map with the updated mapping with the key
- Definition Classes
- MapOps
- def valueStepper[S <: Stepper[_]](implicit shape: StepperShape[V, S]): S
Returns a Stepper for the values of this map.
- def values: collection.Iterable[V]
Collects all values of this map in an iterable collection.
Collects all values of this map in an iterable collection.
- returns
the values of this map as an iterable.
- Definition Classes
- MapOps
- def valuesIterator: Iterator[V]
Creates an iterator for all values in this map.
- def view: MapView[K, V]
A view over the elements of this collection.
A view over the elements of this collection.
- Definition Classes
- MapOps → IterableOps
- def withDefault[V1 >: V](d: (K) => V1): Map[K, V1]
The same map with a given default function.
The same map with a given default function. Note: The default is only used for
apply
. Other methods likeget
,contains
,iterator
,keys
, etc. are not affected bywithDefault
.Invoking transformer methods (e.g.
map
) will not preserve the default value.- d
the function mapping keys to values, used for non-present keys
- returns
a wrapper of the map with a default value
- Definition Classes
- Map
- def withDefaultValue[V1 >: V](d: V1): Map[K, V1]
The same map with a given default value.
The same map with a given default value. Note: The default is only used for
apply
. Other methods likeget
,contains
,iterator
,keys
, etc. are not affected bywithDefaultValue
.Invoking transformer methods (e.g.
map
) will not preserve the default value.- d
default value used for non-present keys
- returns
a wrapper of the map with a default value
- Definition Classes
- Map
- def withFilter(p: ((K, V)) => Boolean): MapOps.WithFilter[K, V, [x]Iterable[x], [x, y]Map[x, y]]
Creates a non-strict filter of this map.
Creates a non-strict filter of this map.
Note: the difference between
c filter p
andc withFilter p
is that the former creates a new collection, whereas the latter only restricts the domain of subsequentmap
,flatMap
,foreach
, andwithFilter
operations.Note: might return different results for different runs, unless the underlying collection type is ordered.
- p
the predicate used to test elements.
- returns
an object of class
WithFilter
, which supportsmap
,flatMap
,foreach
, andwithFilter
operations. All these operations apply to those elements of this map which satisfy the predicatep
.
- Definition Classes
- MapFactoryDefaults → IterableOps
- def zip[B](that: IterableOnce[B]): Iterable[((K, V), B)]
Returns a iterable collection formed from this iterable collection and another iterable collection by combining corresponding elements in pairs.
Returns a iterable collection formed from this iterable collection and another iterable collection by combining corresponding elements in pairs. If one of the two collections is longer than the other, its remaining elements are ignored.
- B
the type of the second half of the returned pairs
- that
The iterable providing the second half of each result pair
- returns
a new iterable collection containing pairs consisting of corresponding elements of this iterable collection and
that
. The length of the returned collection is the minimum of the lengths of this iterable collection andthat
.
- Definition Classes
- StrictOptimizedIterableOps → IterableOps
- def zipAll[A1 >: (K, V), B](that: collection.Iterable[B], thisElem: A1, thatElem: B): Iterable[(A1, B)]
Returns a iterable collection formed from this iterable collection and another iterable collection by combining corresponding elements in pairs.
Returns a iterable collection formed from this iterable collection and another iterable collection by combining corresponding elements in pairs. If one of the two collections is shorter than the other, placeholder elements are used to extend the shorter collection to the length of the longer.
- that
the iterable providing the second half of each result pair
- thisElem
the element to be used to fill up the result if this iterable collection is shorter than
that
.- thatElem
the element to be used to fill up the result if
that
is shorter than this iterable collection.- returns
a new collection of type
That
containing pairs consisting of corresponding elements of this iterable collection andthat
. The length of the returned collection is the maximum of the lengths of this iterable collection andthat
. If this iterable collection is shorter thanthat
,thisElem
values are used to pad the result. Ifthat
is shorter than this iterable collection,thatElem
values are used to pad the result.
- Definition Classes
- IterableOps
- def zipWithIndex: Iterable[((K, V), Int)]
Zips this iterable collection with its indices.
Zips this iterable collection with its indices.
- returns
A new iterable collection containing pairs consisting of all elements of this iterable collection paired with their index. Indices start at
0
.
- Definition Classes
- StrictOptimizedIterableOps → IterableOps → IterableOnceOps
List("a", "b", "c").zipWithIndex == List(("a", 0), ("b", 1), ("c", 2))
Example:
Deprecated Value Members
- def +[V1 >: V](elem1: (K, V1), elem2: (K, V1), elems: (K, V1)*): Map[K, V1]
- Definition Classes
- MapOps
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use ++ with an explicit collection argument instead of + with varargs
- def ++:[V1 >: V](that: IterableOnce[(K, V1)]): Map[K, V1]
- Definition Classes
- MapOps
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use ++ instead of ++: for collections of type Iterable
- def ++:[B >: (K, V)](that: IterableOnce[B]): Iterable[B]
- Definition Classes
- IterableOps
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use ++ instead of ++: for collections of type Iterable
- def -(key1: K, key2: K, keys: K*): Map[K, V]
- Definition Classes
- MapOps
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use -- with an explicit collection
- def /:[B](z: B)(op: (B, (K, V)) => B): B
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)])./:(z)(op)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator.foldLeft instead
- final def /:[B](z: B)(op: (B, (K, V)) => B): B
- Definition Classes
- IterableOnceOps
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use foldLeft instead of /:
- def :\[B](z: B)(op: ((K, V), B) => B): B
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).:\(z)(op)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator.foldRight instead
- final def :\[B](z: B)(op: ((K, V), B) => B): B
- Definition Classes
- IterableOnceOps
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use foldRight instead of :\
- def aggregate[B](z: => B)(seqop: (B, (K, V)) => B, combop: (B, B) => B): B
- Definition Classes
- IterableOnceOps
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0)
aggregate
is not relevant for sequential collections. UsefoldLeft(z)(seqop)
instead.
- def collectFirst[B](f: PartialFunction[(K, V), B]): Option[B]
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).collectFirst(f)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.collectFirst(...) instead
- def companion: IterableFactory[[_]Iterable[_]]
- Definition Classes
- IterableOps
- Annotations
- @deprecated @deprecatedOverriding(message = "Use iterableFactory instead", since = "2.13.0") @inline()
- Deprecated
(Since version 2.13.0) Use iterableFactory instead
- def copyToBuffer(dest: Buffer[(K, V)]): Unit
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).copyToBuffer(dest)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.copyToBuffer(...) instead
- final def copyToBuffer[B >: (K, V)](dest: Buffer[B]): Unit
- Definition Classes
- IterableOnceOps
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use
dest ++= coll
instead
- def count(f: ((K, V)) => Boolean): Int
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).count(f)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.count(...) instead
- def exists(f: ((K, V)) => Boolean): Boolean
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).exists(f)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.exists(...) instead
- def filter(f: ((K, V)) => Boolean): Iterator[(K, V)]
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).filter(f)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.filter(...) instead
- def filterKeys(p: (K) => Boolean): MapView[K, V]
Filters this map by retaining only keys satisfying a predicate.
Filters this map by retaining only keys satisfying a predicate.
- p
the predicate used to test keys
- returns
an immutable map consisting only of those key value pairs of this map where the key satisfies the predicate
p
. The resulting map wraps the original map without copying any elements.
- Definition Classes
- MapOps
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .view.filterKeys(f). A future version will include a strict version of this method (for now, .view.filterKeys(p).toMap).
- def find(p: ((K, V)) => Boolean): Option[(K, V)]
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).find(p)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.find instead
- def flatMap[B](f: ((K, V)) => IterableOnce[B]): IterableOnce[B]
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).flatMap(f)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.flatMap instead or consider requiring an Iterable
- def fold[A1 >: A](z: A1)(op: (A1, A1) => A1): A1
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).fold(z)(op)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.fold instead
- def foldLeft[B](z: B)(op: (B, (K, V)) => B): B
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).foldLeft(z)(op)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator.foldLeft instead
- def foldRight[B](z: B)(op: ((K, V), B) => B): B
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).foldRight(z)(op)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator.foldRight instead
- def forall(f: ((K, V)) => Boolean): Boolean
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).forall(f)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.forall(...) instead
- def foreach[U](f: ((K, V)) => U): Unit
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).foreach(f)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator.foreach(...) instead
- def hasDefiniteSize: Boolean
Tests whether this collection is known to have a finite size.
Tests whether this collection is known to have a finite size. All strict collections are known to have finite size. For a non-strict collection such as
Stream
, the predicate returnstrue
if all elements have been computed. It returnsfalse
if the stream is not yet evaluated to the end. Non-empty Iterators usually returnfalse
even if they were created from a collection with a known finite size.Note: many collection methods will not work on collections of infinite sizes. The typical failure mode is an infinite loop. These methods always attempt a traversal without checking first that
hasDefiniteSize
returnstrue
. However, checkinghasDefiniteSize
can provide an assurance that size is well-defined and non-termination is not a concern.- returns
true
if this collection is known to have finite size,false
otherwise.
- Definition Classes
- IterableOnceOps
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Check .knownSize instead of .hasDefiniteSize for more actionable information (see scaladoc for details)
- See also
method
knownSize
for a more useful alternative
- def isEmpty: Boolean
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).isEmpty
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.isEmpty instead
- def map[B](f: ((K, V)) => B): IterableOnce[B]
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).map(f)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.map instead or consider requiring an Iterable
- def mapValues[W](f: (V) => W): MapView[K, W]
Transforms this map by applying a function to every retrieved value.
Transforms this map by applying a function to every retrieved value.
- f
the function used to transform values of this map.
- returns
a map view which maps every key of this map to
f(this(key))
. The resulting map wraps the original map without copying any elements.
- Definition Classes
- MapOps
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .view.mapValues(f). A future version will include a strict version of this method (for now, .view.mapValues(f).toMap).
- def max(implicit ord: math.Ordering[(K, V)]): (K, V)
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).max(ord)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.max instead
- def maxBy[B](f: ((K, V)) => B)(implicit cmp: math.Ordering[B]): (K, V)
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).maxBy(f)(cmp)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.maxBy(...) instead
- def min(implicit ord: math.Ordering[(K, V)]): (K, V)
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).min(ord)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.min instead
- def minBy[B](f: ((K, V)) => B)(implicit cmp: math.Ordering[B]): (K, V)
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).minBy(f)(cmp)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.minBy(...) instead
- def mkString: String
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).mkString
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.mkString instead
- def mkString(sep: String): String
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).mkString(sep)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.mkString instead
- def mkString(start: String, sep: String, end: String): String
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).mkString(start, sep, end)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.mkString instead
- def nonEmpty: Boolean
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).nonEmpty
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.nonEmpty instead
- def product(implicit num: math.Numeric[(K, V)]): (K, V)
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).product(num)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.product instead
- def reduce(f: ((K, V), (K, V)) => (K, V)): (K, V)
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).reduce(f)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.reduce(...) instead
- def reduceLeft(f: ((K, V), (K, V)) => (K, V)): (K, V)
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).reduceLeft(f)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.reduceLeft(...) instead
- def reduceLeftOption(f: ((K, V), (K, V)) => (K, V)): Option[(K, V)]
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).reduceLeftOption(f)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.reduceLeftOption(...) instead
- def reduceOption(f: ((K, V), (K, V)) => (K, V)): Option[(K, V)]
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).reduceOption(f)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.reduceOption(...) instead
- def reduceRight(f: ((K, V), (K, V)) => (K, V)): (K, V)
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).reduceRight(f)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.reduceRight(...) instead
- def reduceRightOption(f: ((K, V), (K, V)) => (K, V)): Option[(K, V)]
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).reduceRightOption(f)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.reduceRightOption(...) instead
- final def repr: Map[K, V]
- Definition Classes
- IterableOps
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use coll instead of repr in a collection implementation, use the collection value itself from the outside
- def sameElements[B >: A](that: IterableOnce[B]): Boolean
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.sameElements instead
- def seq: Map4.this.type
- Definition Classes
- Iterable
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Iterable.seq always returns the iterable itself
- def size: Int
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).size
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.size instead
- def sum(implicit num: math.Numeric[(K, V)]): (K, V)
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).sum(num)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.sum instead
- def to[C1](factory: Factory[(K, V), C1]): C1
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).to(factory)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.to(factory) instead
- def toArray[B >: A](implicit arg0: ClassTag[B]): Array[B]
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).toArray(arg0)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.toArray
- def toBuffer[B >: A]: Buffer[B]
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).toBuffer
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.to(ArrayBuffer) instead
- def toIndexedSeq: collection.IndexedSeq[(K, V)]
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).toIndexedSeq
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.toIndexedSeq instead
- final def toIterable: collection.Iterable[(K, V)]
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).toIterable
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator.to(Iterable) instead
- def toIterator: Iterator[(K, V)]
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).toIterator
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator instead
- final def toIterator: Iterator[(K, V)]
- Definition Classes
- IterableOnceOps
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator instead of .toIterator
- def toList: List[(K, V)]
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).toList
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.to(List) instead
- def toMap[K, V](implicit ev: <:<[(K, V), (K, V)]): Map[K, V]
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).toMap(ev)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.to(Map) instead
- def toSeq: Seq[(K, V)]
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).toSeq
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator.to(Seq) instead
- def toSet[B >: A]: Set[B]
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).toSet
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator.to(Set) instead
- def toStream: Stream[(K, V)]
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).toStream
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator.to(LazyList) instead
- final def toStream: Stream[(K, V)]
- Definition Classes
- IterableOnceOps
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .to(LazyList) instead of .toStream
- final def toTraversable: collection.Traversable[(K, V)]
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).toTraversable
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator.to(Iterable) instead
- final def toTraversable: collection.Traversable[(K, V)]
Converts this iterable collection to an unspecified Iterable.
Converts this iterable collection to an unspecified Iterable. Will return the same collection if this instance is already Iterable.
- returns
An Iterable containing all elements of this iterable collection.
- Definition Classes
- IterableOps
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use toIterable instead
- def toVector: Vector[(K, V)]
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).toVector
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator.to(Vector) instead
- def view(from: Int, until: Int): View[(K, V)]
A view over a slice of the elements of this collection.
A view over a slice of the elements of this collection.
- Definition Classes
- IterableOps
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .view.slice(from, until) instead of .view(from, until)
- def withFilter(f: ((K, V)) => Boolean): Iterator[(K, V)]
- Implicit
- This member is added by an implicit conversion from Map4[K, V] toIterableOnceExtensionMethods[(K, V)] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(map4: IterableOnceExtensionMethods[(K, V)]).withFilter(f)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.withFilter(...) instead
This is the documentation for the Scala standard library.
Package structure
The scala package contains core types like
Int
,Float
,Array
orOption
which are accessible in all Scala compilation units without explicit qualification or imports.Notable packages include:
scala.collection
and its sub-packages contain Scala's collections frameworkscala.collection.immutable
- Immutable, sequential data-structures such asVector
,List
,Range
,HashMap
orHashSet
scala.collection.mutable
- Mutable, sequential data-structures such asArrayBuffer
,StringBuilder
,HashMap
orHashSet
scala.collection.concurrent
- Mutable, concurrent data-structures such asTrieMap
scala.concurrent
- Primitives for concurrent programming such asFutures
andPromises
scala.io
- Input and output operationsscala.math
- Basic math functions and additional numeric types likeBigInt
andBigDecimal
scala.sys
- Interaction with other processes and the operating systemscala.util.matching
- Regular expressionsOther packages exist. See the complete list on the right.
Additional parts of the standard library are shipped as separate libraries. These include:
scala.reflect
- Scala's reflection API (scala-reflect.jar)scala.xml
- XML parsing, manipulation, and serialization (scala-xml.jar)scala.collection.parallel
- Parallel collections (scala-parallel-collections.jar)scala.util.parsing
- Parser combinators (scala-parser-combinators.jar)scala.swing
- A convenient wrapper around Java's GUI framework called Swing (scala-swing.jar)Automatic imports
Identifiers in the scala package and the
scala.Predef
object are always in scope by default.Some of these identifiers are type aliases provided as shortcuts to commonly used classes. For example,
List
is an alias forscala.collection.immutable.List
.Other aliases refer to classes provided by the underlying platform. For example, on the JVM,
String
is an alias forjava.lang.String
.