WithDefault
Related Doc:
package Map
The implementation class of the set returned by keySet.
The implementation class of the set returned by keySet.
The implementation class of the iterable returned by values.
The implementation class of the iterable returned by values.
The type implementing this traversable
The type implementing this traversable
A class supporting filtered operations.
A class supporting filtered operations. Instances of this class are
returned by method withFilter.
Test two objects for inequality.
Test two objects for inequality.
true if !(this == that), false otherwise.
Equivalent to x.hashCode except for boxed numeric types and null.
Equivalent to x.hashCode except for boxed numeric types and null.
For numerics, it returns a hash value which is consistent
with value equality: if two value type instances compare
as true, then ## will produce the same hash value for each
of them.
For null returns a hashcode where null.hashCode throws a
NullPointerException.
a hash value consistent with ==
Creates a new map containing a new key/value mapping and all the key/value mappings of this map.
Creates a new map containing a new key/value mapping and all the key/value mappings of this map.
Mapping kv will override existing mappings from this map with the same key.
the type of the value in the key/value pair.
the key/value mapping to be added
a new map containing mappings of this map and the mapping kv.
Creates a new map containing two or more key/value mappings and all the key/value mappings of this map.
Creates a new map containing two or more key/value mappings and all the key/value mappings of this map.
Specified mappings will override existing mappings from this map with the same keys.
the type of the added values
the first element to add.
the second element to add.
the remaining elements to add.
a new map containing mappings of this map and two or more specified mappings.
Creates a new map containing the key/value mappings provided by the specified traversable object and all the key/value mappings of this map.
Creates a new map containing the key/value mappings provided by the specified traversable object and all the key/value mappings of this map.
Note that existing mappings from this map with the same key as those in xs will be overridden.
the type of the added values
the traversable object.
a new map containing mappings of this map and those provided by xs.
[use case] Returns a new mutable map containing the elements from the left hand operand followed by the elements from the right hand operand.
Returns a new mutable map containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the mutable map is the most specific superclass encompassing the element types of the two operands.
Example:
scala> val a = List(1) a: List[Int] = List(1) scala> val b = List(2) b: List[Int] = List(2) scala> val c = a ++ b c: List[Int] = List(1, 2) scala> val d = List('a') d: List[Char] = List(a) scala> val e = c ++ d e: List[AnyVal] = List(1, 2, a)
the element type of the returned collection.
the traversable to append.
a new mutable map which contains all elements of this mutable map
followed by all elements of that.
As with ++, returns a new collection containing the elements from the
left operand followed by the elements from the right operand.
As with ++, returns a new collection containing the elements from the
left operand followed by the elements from the right operand.
It differs from ++ in that the right operand determines the type of
the resulting collection rather than the left one.
Mnemonic: the COLon is on the side of the new COLlection type.
Example:
scala> val x = List(1) x: List[Int] = List(1) scala> val y = LinkedList(2) y: scala.collection.mutable.LinkedList[Int] = LinkedList(2) scala> val z = x ++: y z: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2)
This overload exists because: for the implementation of ++: we should
reuse that of ++ because many collections override it with more
efficient versions.
Since TraversableOnce has no ++ method, we have to implement that
directly, but Traversable and down can use the overload.
the element type of the returned collection.
the class of the returned collection. Where possible, That is
the same class as the current collection class Repr, but this
depends on the element type B being admissible for that class,
which means that an implicit instance of type CanBuildFrom[Repr, B, That]
is found.
the traversable to append.
an implicit value of class CanBuildFrom which determines
the result class That from the current representation type Repr and
and the new element type B.
a new collection of type That which contains all elements
of this traversable collection followed by all elements of that.
[use case] As with ++, returns a new collection containing the elements from the left operand followed by the
elements from the right operand.
As with ++, returns a new collection containing the elements from the left operand followed by the
elements from the right operand.
It differs from ++ in that the right operand determines the type of
the resulting collection rather than the left one.
Mnemonic: the COLon is on the side of the new COLlection type.
Example:
scala> val x = List(1) x: List[Int] = List(1) scala> val y = LinkedList(2) y: scala.collection.mutable.LinkedList[Int] = LinkedList(2) scala> val z = x ++: y z: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2)
the element type of the returned collection.
the traversable to append.
a new mutable map which contains all elements of this mutable map
followed by all elements of that.
adds all elements produced by a TraversableOnce to this growable collection.
adds all elements produced by a TraversableOnce to this growable collection.
the TraversableOnce producing the elements to add.
the growable collection itself.
Adds a new key/value pair to this map.
Adds a new key/value pair to this map. If the map already contains a mapping for the key, it will be overridden by the new value.
the key/value pair.
the map itself
adds two or more elements to this growable collection.
adds two or more elements to this growable collection.
the first element to add.
the second element to add.
the remaining elements to add.
the growable collection itself
Creates a new map with all the key/value mappings of this map except the key/value mapping with the specified key.
Creates a new map with all the key/value mappings of this map except the key/value mapping with the specified key.
the key to be removed
a new map with all the mappings of this map except that with a key key.
Creates a new map with all the key/value mappings of this map except mappings with keys equal to any of the two or more specified keys.
Creates a new map with all the key/value mappings of this map except mappings with keys equal to any of the two or more specified keys.
the first element to remove.
the second element to remove.
the remaining elements to remove.
a new map containing all the mappings of this map except mappings
with a key equal to elem1, elem2 or any of elems.
(Changed in version 2.8.0) - creates a new map. Use -= to remove an element from this map and return that map itself.
Creates a new map with all the key/value mappings of this map except mappings with keys equal to any of those provided by the specified traversable object.
Creates a new map with all the key/value mappings of this map except mappings with keys equal to any of those provided by the specified traversable object.
the traversable object.
a new map with all the key/value mappings of this map except mappings
with a key equal to a key from xs.
(Changed in version 2.8.0) -- creates a new map. Use --= to remove an element from this map and return that map itself.
Removes all elements produced by an iterator from this shrinkable collection.
Removes all elements produced by an iterator from this shrinkable collection.
the iterator producing the elements to remove.
the shrinkable collection itself
Removes a key from this map.
Removes a key from this map.
the key to be removed
the map itself.
Removes two or more elements from this shrinkable collection.
Removes two or more elements from this shrinkable collection.
the first element to remove.
the second element to remove.
the remaining elements to remove.
the shrinkable collection itself
Applies a binary operator to a start value and all elements of this traversable or iterator, going left to right.
Applies a binary operator to a start value and all elements of this traversable or iterator, going left to right.
Note: /: is alternate syntax for foldLeft; z /: xs is the same as
xs foldLeft z.
Examples:
Note that the folding function used to compute b is equivalent to that used to compute c.
scala> val a = List(1,2,3,4) a: List[Int] = List(1, 2, 3, 4) scala> val b = (5 /: a)(_+_) b: Int = 15 scala> val c = (5 /: a)((x,y) => x + y) c: Int = 15
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.
the result type of the binary operator.
the start value.
the binary operator.
the result of inserting op between consecutive elements of this traversable or iterator,
going left to right with the start value z on the left:
op(...op(op(z, x_1), x_2), ..., x_n)
where x1, ..., xn are the elements of this traversable or iterator.
Applies a binary operator to all elements of this traversable or iterator and a start value, going right to left.
Applies a binary operator to all elements of this traversable or iterator and a start value, going right to left.
Note: :\ is alternate syntax for foldRight; xs :\ z is the same as
xs foldRight z.
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.
Examples:
Note that the folding function used to compute b is equivalent to that used to compute c.
scala> val a = List(1,2,3,4) a: List[Int] = List(1, 2, 3, 4) scala> val b = (a :\ 5)(_+_) b: Int = 15 scala> val c = (a :\ 5)((x,y) => x + y) c: Int = 15
the result type of the binary operator.
the start value
the binary operator
the result of inserting op between consecutive elements of this traversable or iterator,
going right to left with the start value z on the right:
op(x_1, op(x_2, ... op(x_n, z)...))
where x1, ..., xn are the elements of this traversable or iterator.
The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).
The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).
true if the receiver object is equivalent to the argument; false otherwise.
Appends all bindings of this map to a string builder using start, end, and separator strings.
Appends all bindings 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 string
end. Inside, the string representations of all bindings of this map
in the form of key -> value are separated by the string sep.
the builder to which strings are appended.
the starting string.
the separator string.
the ending string.
the string builder b to which elements were appended.
Appends all elements of this traversable or iterator to a string builder.
Appends all elements of this traversable or iterator to a string builder.
The written text consists of the string representations (w.r.t. the method
toString) of all elements of this traversable or iterator 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
the string builder to which elements are appended.
the string builder b to which elements were appended.
Appends all elements of this traversable or iterator to a string builder using a separator string.
Appends all elements of this traversable or iterator 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 traversable or iterator, separated by the string sep.
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
the string builder to which elements are appended.
the separator string.
the string builder b to which elements were appended.
Aggregates the results of applying an operator to subsequent elements.
Aggregates the results of applying an operator to subsequent elements.
This is a more general form of fold and reduce. It is similar to
foldLeft in that it doesn't require the result to be a supertype of the
element type. In addition, it allows parallel collections to be processed
in chunks, and then combines the intermediate results.
aggregate splits the traversable or iterator into partitions and processes each
partition by sequentially applying seqop, starting with z (like
foldLeft). Those intermediate results are then combined by using
combop (like fold). The implementation of this operation may operate
on an arbitrary number of collection partitions (even 1), so combop may
be invoked an arbitrary number of times (even 0).
As an example, consider summing up the integer values of a list of chars.
The initial value for the sum is 0. First, seqop transforms each input
character to an Int and adds it to the sum (of the partition). Then,
combop just needs to sum up the intermediate results of the partitions:
List('a', 'b', 'c').aggregate(0)({ (sum, ch) => sum + ch.toInt }, { (p1, p2) => p1 + p2 })
the type of accumulated results
the initial value for the accumulated result of the partition - this
will typically be the neutral element for the seqop operator (e.g.
Nil for list concatenation or 0 for summation) and may be evaluated
more than once
an operator used to accumulate results within a partition
an associative operator used to combine results from different partitions
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.
the result type of the transformation function.
the transformation function
a partial function with the same domain as this partial function, which maps
arguments x to k(this(x)).
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, the default method throws a
NoSuchElementException.
the key
the value associated with the given key, or the result of the
map's default method, if none exists.
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 to
if(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 an applyOrElse implementation which
avoids double evaluation of pattern matchers and guards.
This makes applyOrElse the basis for the efficient implementation for many operations and scenarios, such as:
orElse/andThen chains does not lead to
excessive apply/isDefinedAt evaluationlift and unlift 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 override applyOrElse with custom implementation that avoids
double isDefinedAt evaluation. This may result in better performance
and more predictable behavior w.r.t. side effects.
the function argument
the fallback function
the result of this function or fallback function application.
2.10
Cast the receiver object to be of type T0.
Cast the receiver object to be of type T0.
Note that the success of a cast at runtime is modulo Scala's erasure semantics.
Therefore the expression 1.asInstanceOf[String] will throw a ClassCastException at
runtime, while the expression List(1).asInstanceOf[List[String]] will not.
In the latter example, because the type argument is erased as part of compilation it is
not possible to check whether the contents of the list are of the requested type.
the receiver object.
ClassCastException if the receiver object is not an instance of the erasure of type T0.
Method called from equality methods, so that user-defined subclasses can refuse to be equal to other collections of the same kind.
Method called from equality methods, so that user-defined subclasses can refuse to be equal to other collections of the same kind.
The object with which this iterable collection should be compared
true, if this iterable collection can possibly equal that, false otherwise. The test
takes into consideration only the run-time types of objects but ignores their elements.
Removes all bindings from the map.
Create a copy of the receiver object.
[use case] Builds a new collection by applying a partial function to all elements of this mutable map on which the function is defined.
Builds a new collection by applying a partial function to all elements of this mutable map on which the function is defined.
the element type of the returned collection.
the partial function which filters and maps the mutable map.
a new mutable 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.
Finds the first element of the traversable or iterator for which the given partial function is defined, and applies the partial function to it.
Finds the first element of the traversable or iterator 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.
the partial function
an option value containing pf applied to the first
value for which it is defined, or None if none exists.
Seq("a", 1, 5L).collectFirst({ case x: Int => x*10 }) = Some(10)
The factory companion object that builds instances of class Iterable.
The factory companion object that builds instances of class Iterable.
(or its Iterable superclass where class Iterable is not a Seq.)
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.
the type to which function g can be applied
a function A => T1
a new function f such that f(x) == apply(g(x))
Tests whether this map contains a binding for a key.
Tests whether this map contains a binding for a key.
the key
true if there is a binding for key in this map, false otherwise.
[use case] Copies the elements of this mutable map to an array.
Copies the elements of this mutable map to an array.
Fills the given array xs with at most len elements of
this mutable map, starting at position start.
Copying will stop once either the end of the current mutable map is reached,
or the end of the target array is reached, or len elements have been copied.
the array to fill.
the starting index.
the maximal number of elements to copy.
[use case] Copies the elements of this mutable map to an array.
Copies the elements of this mutable map to an array.
Fills the given array xs with values of this mutable map.
Copying will stop once either the end of the current mutable map is reached,
or the end of the target array is reached.
the array to fill.
[use case] Copies the elements of this mutable map to an array.
Copies the elements of this mutable map to an array.
Fills the given array xs with values of this mutable map, beginning at index start.
Copying will stop once either the end of the current mutable map is reached,
or the end of the target array is reached.
the array to fill.
the starting index.
Copies all elements of this traversable or iterator to a buffer.
Copies all elements of this traversable or iterator to a buffer.
Note: will not terminate for infinite-sized collections.
The buffer to which elements are copied.
Counts the number of elements in the traversable or iterator which satisfy a predicate.
Counts the number of elements in the traversable or iterator which satisfy a predicate.
the predicate used to test elements.
the number of elements satisfying the predicate p.
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.
the given key value for which a binding is missing.
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.
the number of elements to drop from this iterable collection.
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 than n elements.
Selects all elements except last n ones.
Selects all elements except last n ones.
Note: might return different results for different runs, unless the underlying collection type is ordered.
The number of elements to take
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 than n elements.
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.
the longest suffix of this traversable collection whose first element
does not satisfy the predicate p.
The empty map of the same type as this map
The empty map of the same type as this map
an empty map of type This.
Tests whether the argument (that) is a reference to the receiver object (this).
Tests whether the argument (that) is a reference to the receiver object (this).
The eq method implements an equivalence relation on
non-null instances of AnyRef, and has three additional properties:
x and y of type AnyRef, multiple invocations of
x.eq(y) consistently returns true or consistently returns false.x of type AnyRef, x.eq(null) and null.eq(x) returns false.null.eq(null) returns true. When overriding the equals or hashCode methods, it is important to ensure that their behavior is
consistent with reference equality. Therefore, if two objects are references to each other (o1 eq o2), they
should be equal to each other (o1 == o2) and they should hash to the same value (o1.hashCode == o2.hashCode).
true if the argument is a reference to the receiver object; false otherwise.
Compares two maps structurally; i.e., checks if all mappings contained in this map are also contained in the other map, and vice versa.
Compares two maps structurally; i.e., checks if all mappings contained in this map are also contained in the other map, and vice versa.
the other map
true if both maps contain exactly the
same mappings, false otherwise.
Tests whether a predicate holds for at least one element of this iterable collection.
Tests whether a predicate holds for at least one element of this iterable collection.
Note: may not terminate for infinite-sized collections.
the predicate used to test elements.
false if this iterable collection is empty, otherwise true if the given predicate p
holds for some of the elements of this iterable collection, otherwise false
Selects all elements of this traversable collection which satisfy a predicate.
Selects all elements of this traversable collection which satisfy a predicate.
the predicate used to test elements.
a new traversable collection consisting of all elements of this traversable collection that satisfy the given
predicate p. The order of the elements is preserved.
Filters this map by retaining only keys satisfying a predicate.
Filters this map by retaining only keys satisfying a predicate.
the predicate used to test keys
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.
Returns a new map obtained by removing all key/value pairs for which the predicate
p returns true.
Returns a new map obtained by removing all key/value pairs for which the predicate
p returns true.
Note: This method works by successively removing elements for which the
predicate is true from this set.
If removal is slow, or you expect that most elements of the set
will be removed, you might consider using filter
with a negated predicate instead.
A predicate over key-value pairs
A new map containing elements not satisfying the predicate.
Called by the garbage collector on the receiver object when there are no more references to the object.
Called by the garbage collector on the receiver object when there are no more references to the object.
The details of when and if the finalize method is invoked, as
well as the interaction between finalize and non-local returns
and exceptions, are all platform dependent.
Finds the first element of the iterable collection satisfying a predicate, if any.
Finds the first element of the iterable 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.
the predicate used to test elements.
an option value containing the first element in the iterable collection
that satisfies p, or None if none exists.
[use case] Builds a new collection by applying a function to all elements of this mutable map and using the elements of the resulting collections.
Builds a new collection by applying a function to all elements of this mutable map 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 mutable map. 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 => 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)
the element type of the returned collection.
the function to apply to each element.
a new mutable map resulting from applying the given collection-valued function
f to each element of this mutable map and concatenating the results.
[use case] Converts this mutable map of traversable collections into a mutable map formed by the elements of these traversable collections.
Converts this mutable map of traversable collections into a mutable map formed by the elements of these traversable collections.
The resulting collection's type will be guided by the static type of mutable map. 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)
the type of the elements of each traversable collection.
a new mutable map resulting from concatenating all element mutable maps.
Folds the elements of this traversable or iterator using the specified associative binary operator.
Folds the elements of this traversable or iterator using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
Note: will not terminate for infinite-sized collections.
a type parameter for the binary operator, a supertype of A.
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).
a binary operator that must be associative.
the result of applying the fold operator op between all the elements and z, or z if this traversable or iterator is empty.
Applies a binary operator to a start value and all elements of this traversable or iterator, going left to right.
Applies a binary operator to a start value and all elements of this traversable or iterator, 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.
the result type of the binary operator.
the start value.
the binary operator.
the result of inserting op between consecutive elements of this traversable or iterator,
going left to right with the start value z on the left:
op(...op(z, x_1), x_2, ..., x_n)
where x1, ..., xn are the elements of this traversable or iterator.
Returns z if this traversable or iterator is empty.
Applies a binary operator to all elements of this iterable collection and a start value, going right to left.
Applies a binary operator to all elements of this iterable 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.
the result type of the binary operator.
the start value.
the binary operator.
the result of inserting op between consecutive elements of this iterable collection,
going right to left with the start value z on the right:
op(x_1, op(x_2, ... op(x_n, z)...))
where x1, ..., xn are the elements of this iterable collection.
Returns z if this iterable collection is empty.
Tests whether a predicate holds for all elements of this iterable collection.
Tests whether a predicate holds for all elements of this iterable collection.
Note: may not terminate for infinite-sized collections.
the predicate used to test elements.
true if this iterable collection is empty or the given predicate p
holds for all elements of this iterable collection, otherwise false.
[use case] Applies a function f to all elements of this mutable map.
Applies a function f to all elements of this mutable map.
Note: this method underlies the implementation of most other bulk operations. Subclasses should re-implement this method if a more efficient implementation exists.
the function that is applied for its side-effect to every element.
The result of function f is discarded.
Returns string formatted according to given format string.
Returns string formatted according to given format string.
Format strings are as for String.format
(@see java.lang.String.format).
The generic builder that builds instances of Traversable at arbitrary element types.
The generic builder that builds instances of Traversable at arbitrary element types.
Optionally returns the value associated with a key.
Optionally returns the value associated with a key.
the key value
an option value containing the value associated with key in this map,
or None if none exists.
A representation that corresponds to the dynamic class of the receiver object.
A representation that corresponds to the dynamic class of the receiver object.
The nature of the representation is platform dependent.
a representation that corresponds to the dynamic class of the receiver object.
not specified by SLS as a member of AnyRef
[use case] 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.
the key.
a computation that yields a default value in case no binding for key is
found in the map.
the value associated with key if it exists,
otherwise the result of the default computation.
If given key is already in this map, returns associated value.
If given key is already in this map, returns associated value.
Otherwise, computes value from given expression op, stores with key
in map and returns that value.
Concurrent map implementations may evaluate the expression op
multiple times, or may evaluate op without inserting the result.
the key to test
the computation yielding the value to associate with key, if
key is previously unbound.
the value associated with key (either previously or as a result of executing the method).
Partitions this traversable collection into a map of traversable collections according to some discriminator function.
Partitions this traversable collection into a map of traversable collections according to some discriminator function.
Note: this method is not re-implemented by views. This means when applied to a view it will always force the view and return a new traversable collection.
the type of keys returned by the discriminator function.
the discriminator function.
A map from keys to traversable 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 traversable collection of those elements x
for which f(x) equals k.
Partitions elements in fixed size iterable collections.
Partitions elements in fixed size iterable collections.
the number of elements per group
An iterator producing iterable collections of size size, except the
last will be less than size size if the elements don't divide evenly.
scala.collection.Iterator, method grouped
Tests whether this traversable collection is known to have a finite size.
Tests whether this traversable 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 returns true if all
elements have been computed. It returns false if the stream is
not yet evaluated to the end. Non-empty Iterators usually return
false 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 returns true.
However, checking hasDefiniteSize can provide an assurance that size is
well-defined and non-termination is not a concern.
true if this collection is known to have finite size,
false otherwise.
The hashCode method for reference types.
The hashCode method for reference types. See hashCode in scala.Any.
the hash code value for this object.
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.
the first element of this iterable collection.
NoSuchElementException if the iterable collection is empty.
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.
the first element of this traversable collection if it is nonempty,
None if it is empty.
Selects all elements except the last.
Selects all elements except the last.
Note: might return different results for different runs, unless the underlying collection type is ordered.
a traversable collection consisting of all elements of this traversable collection except the last one.
UnsupportedOperationException if the traversable collection is empty.
Iterates over the inits of this traversable collection.
Iterates over the inits of this traversable collection. The first value will be this
traversable collection and the final one will be an empty traversable collection, with the intervening
values the results of successive applications of init.
an iterator over all the inits of this traversable collection
List(1,2,3).inits = Iterator(List(1,2,3), List(1,2), List(1), Nil)
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 to contains.
the key
true if there is a binding for key in this map, false otherwise.
Tests whether the map is empty.
Tests whether the map is empty.
true if the map does not contain any key/value binding, false otherwise.
Test whether the dynamic type of the receiver object is T0.
Test whether the dynamic type of the receiver object is T0.
Note that the result of the test is modulo Scala's erasure semantics.
Therefore the expression 1.isInstanceOf[String] will return false, while the
expression List(1).isInstanceOf[List[String]] will return true.
In the latter example, because the type argument is erased as part of compilation it is
not possible to check whether the contents of the list are of the specified type.
true if the receiver object is an instance of erasure of type T0; false otherwise.
Tests whether this traversable collection can be repeatedly traversed.
Tests whether this traversable collection can be repeatedly traversed.
true
Creates a new iterator over all key/value pairs of this map
Creates a new iterator over all key/value pairs of this map
the new iterator
Collects all keys of this map in a set.
Collects all keys of this map in a set.
a set containing all keys of this map.
Collects all keys of this map in an iterable collection.
Collects all keys of this map in an iterable collection.
the keys of this map as an iterable.
(Changed in version 2.8.0) keys returns Iterable[A] rather than Iterator[A].
Creates an iterator for all keys.
Creates an iterator for all keys.
an iterator over all keys.
Selects the last element.
Selects the last element.
Note: might return different results for different runs, unless the underlying collection type is ordered.
The last element of this traversable collection.
NoSuchElementException If the traversable collection is empty.
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.
the last element of this traversable collection$ if it is nonempty,
None if it is empty.
Turns this partial function into a plain function returning an Option result.
Turns this partial function into a plain function returning an Option result.
a function that takes an argument x to Some(this(x)) if this
is defined for x, and to None otherwise.
Function.unlift
[use case] Builds a new collection by applying a function to all elements of this mutable map.
Builds a new collection by applying a function to all elements of this mutable map.
the element type of the returned collection.
the function to apply to each element.
a new mutable map resulting from applying the given function
f to each element of this mutable map and collecting the results.
Creates a new builder by applying a transformation function to the results of this builder.
Creates a new builder by applying a transformation function to the results of this builder.
the type of collection returned by f.
the transformation function.
a new builder which is the same as the current builder except that a transformation function is applied to this builder's result.
Transforms this map by applying a function to every retrieved value.
Transforms this map by applying a function to every retrieved value.
the function used to transform values of this map.
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.
[use case] Finds the largest element.
Finds the largest element.
the largest element of this mutable map.
[use case] 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.
The result type of the function f.
The measuring function.
the first element of this mutable map with the largest value measured by function f.
[use case] Finds the smallest element.
Finds the smallest element.
the smallest element of this mutable map
[use case] 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.
The result type of the function f.
The measuring function.
the first element of this mutable map with the smallest value measured by function f.
Displays all elements of this traversable or iterator in a string.
Displays all elements of this traversable or iterator in a string.
a string representation of this traversable or iterator. In the resulting string
the string representations (w.r.t. the method toString)
of all elements of this traversable or iterator follow each other without any
separator string.
Displays all elements of this traversable or iterator in a string using a separator string.
Displays all elements of this traversable or iterator in a string using a separator string.
the separator string.
a string representation of this traversable or iterator. In the resulting string
the string representations (w.r.t. the method toString)
of all elements of this traversable or iterator are separated by the string sep.
List(1, 2, 3).mkString("|") = "1|2|3"
Displays all elements of this traversable or iterator in a string using start, end, and separator strings.
Displays all elements of this traversable or iterator in a string using start, end, and separator strings.
the starting string.
the separator string.
the ending string.
a string representation of this traversable or iterator. The resulting string
begins with the string start and ends with the string
end. Inside, the string representations (w.r.t. the method
toString) of all elements of this traversable or iterator are separated by
the string sep.
List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"
Equivalent to !(this eq that).
Equivalent to !(this eq that).
true if the argument is not a reference to the receiver object; false otherwise.
A common implementation of newBuilder for all mutable maps
in terms of empty.
A common implementation of newBuilder for all mutable maps
in terms of empty.
Overrides MapLike implementation for better efficiency.
Tests whether the traversable or iterator is not empty.
Tests whether the traversable or iterator is not empty.
true if the traversable or iterator contains at least one element, false otherwise.
Wakes up a single thread that is waiting on the receiver object's monitor.
Wakes up a single thread that is waiting on the receiver object's monitor.
not specified by SLS as a member of AnyRef
Wakes up all threads that are waiting on the receiver object's monitor.
Wakes up all threads that are waiting on the receiver object's monitor.
not specified by SLS as a member of AnyRef
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.
the argument type of the fallback function
the result type of the fallback function
the fallback function
a partial function which has as domain the union of the domains
of this partial function and that. The resulting partial function
takes x to this(x) where this is defined, and to that(x) where it is not.
Returns a parallel implementation of this collection.
Returns a parallel implementation of this collection.
For most collection types, this method creates a new parallel collection by copying
all the elements. For these collection, par takes linear time. Mutable collections
in this category do not produce a mutable parallel collection that has the same
underlying dataset, so changes in one collection will not be reflected in the other one.
Specific collections (e.g. ParArray or mutable.ParHashMap) override this default
behaviour by creating a parallel collection which shares the same underlying dataset.
For these collections, par takes constant or sublinear time.
All parallel collections return a reference to themselves.
a parallel implementation of this collection
The default par implementation uses the combiner provided by this method
to create a new parallel collection.
The default par implementation uses the combiner provided by this method
to create a new parallel collection.
a combiner for the parallel collection of type ParRepr
Partitions this traversable collection in two traversable collections according to a predicate.
Partitions this traversable collection in two traversable collections according to a predicate.
the predicate on which to partition.
a pair of traversable collections: the first traversable collection consists of all elements that
satisfy the predicate p and the second traversable collection consists of all elements
that don't. The relative order of the elements in the resulting traversable collections
is the same as in the original traversable collection.
[use case] Multiplies up the elements of this collection.
Multiplies up the elements of this collection.
the product of all elements in this mutable map of numbers of type Int.
Instead of Int, any other type T with an implicit Numeric[T] implementation
can be used as element type of the mutable map and as result type of product.
Examples of such types are: Long, Float, Double, BigInt.
Adds a new key/value pair to this map and optionally returns previously bound value.
Adds a new key/value pair to this map and optionally returns previously bound value. If the map already contains a mapping for the key, it will be overridden by the new value.
the key to update
the new value
an option value containing the value associated with the key
before the put operation was executed, or None if key
was not defined in the map before.
Reduces the elements of this traversable or iterator using the specified associative binary operator.
Reduces the elements of this traversable or iterator using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
A type parameter for the binary operator, a supertype of A.
A binary operator that must be associative.
The result of applying reduce operator op between all the elements if the traversable or iterator is nonempty.
UnsupportedOperationException
if this traversable or iterator is empty.
Applies a binary operator to all elements of this traversable or iterator, going left to right.
Applies a binary operator to all elements of this traversable or iterator, 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.
the result type of the binary operator.
the binary operator.
the result of inserting op between consecutive elements of this traversable or iterator,
going left to right:
op( op( ... op(x_1, x_2) ..., x_{n-1}), x_n) where x1, ..., xn are the elements of this traversable or iterator.
UnsupportedOperationException if this traversable or iterator is empty.
Optionally applies a binary operator to all elements of this traversable or iterator, going left to right.
Optionally applies a binary operator to all elements of this traversable or iterator, 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.
the result type of the binary operator.
the binary operator.
an option value containing the result of reduceLeft(op) if this traversable or iterator is nonempty,
None otherwise.
Reduces the elements of this traversable or iterator, if any, using the specified associative binary operator.
Reduces the elements of this traversable or iterator, if any, using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
A type parameter for the binary operator, a supertype of A.
A binary operator that must be associative.
An option value containing result of applying reduce operator op between all
the elements if the collection is nonempty, and None otherwise.
Applies a binary operator to all elements of this iterable collection, going right to left.
Applies a binary operator to all elements of this iterable 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.
the result type of the binary operator.
the binary operator.
the result of inserting op between consecutive elements of this iterable 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 iterable collection.
UnsupportedOperationException if this iterable collection is empty.
Optionally applies a binary operator to all elements of this traversable or iterator, going right to left.
Optionally applies a binary operator to all elements of this traversable or iterator, 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.
the result type of the binary operator.
the binary operator.
an option value containing the result of reduceRight(op) if this traversable or iterator is nonempty,
None otherwise.
Removes a key from this map, returning the value associated previously with that key as an option.
Removes a key from this map, returning the value associated previously with that key as an option.
the key to be removed
an option value containing the value associated previously with key,
or None if key was not defined in the map before.
The collection of type traversable collection underlying this TraversableLike object.
The collection of type traversable collection underlying this TraversableLike object.
By default this is implemented as the TraversableLike object itself,
but this can be overridden.
The result when this map is used as a builder
Retains only those mappings for which the predicate
p returns true.
Retains only those mappings for which the predicate
p returns true.
The test predicate
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 to
if(pf isDefinedAt x) { action(pf(x)); true } else false
except that runWith is implemented via applyOrElse and thus potentially more efficient.
Using runWith avoids double evaluation of pattern matchers and guards for partial function literals.
the action function
a function which maps arguments x to isDefinedAt(x). The resulting function
runs action(this(x)) where this is defined.
2.10
applyOrElse.
[use case] Checks if the other iterable collection contains the same elements in the same order as this mutable map.
Checks if the other iterable collection contains the same elements in the same order as this mutable map.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the collection to compare with.
true, if both collections contain the same elements in the same order, false otherwise.
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.
element type of the resulting collection
type of the resulting collection
neutral element for the operator op
the associative operator for the scan
combiner factory which provides a combiner
a new traversable collection containing the prefix scan of the elements in this traversable collection
Produces a collection containing cumulative results of applying the operator going left to right.
Produces a collection containing cumulative results of applying the operator 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.
the type of the elements in the resulting collection
the actual type of the resulting collection
the initial value
the binary operator applied to the intermediate result and the element
an implicit value of class CanBuildFrom which determines
the result class That from the current representation type Repr and
and the new element type B.
collection with intermediate results
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.
Example:
List(1, 2, 3, 4).scanRight(0)(_ + _) == List(10, 9, 7, 4, 0)
the type of the elements in the resulting collection
the actual type of the resulting collection
the initial value
the binary operator applied to the intermediate result and the element
an implicit value of class CanBuildFrom which determines
the result class That from the current representation type Repr and
and the new element type B.
collection with intermediate results
(Changed in version 2.9.0) The behavior of scanRight has changed. The previous behavior can be reproduced with scanRight.reverse.
A version of this collection with all of the operations implemented sequentially (i.e., in a single-threaded manner).
A version of this collection with all of the operations implemented sequentially (i.e., in a single-threaded manner).
This method returns a reference to this collection. In parallel collections, it is redefined to return a sequential implementation of this collection. In both cases, it has O(1) complexity.
a sequential view of the collection.
The size of this map.
The size of this map.
the number of elements in this map.
Gives a hint that one expects the result of this builder
to have the same size as the given collection, plus some delta.
Gives a hint that one expects the result of this builder
to have the same size as the given collection, plus some delta. This will
provide a hint only if the collection is known to have a cheap
size method. Currently this is assumed to be the case if and only if
the collection is of type IndexedSeqLike.
Some builder classes
will optimize their representation based on the hint. However,
builder implementations are still required to work correctly even if the hint is
wrong, i.e. a different number of elements is added.
the collection which serves as a hint for the result's size.
a correction to add to the coll.size to produce the size hint.
Gives a hint that one expects the result of this builder
to have the same size as the given collection, plus some delta.
Gives a hint that one expects the result of this builder
to have the same size as the given collection, plus some delta. This will
provide a hint only if the collection is known to have a cheap
size method. Currently this is assumed to be the case if and only if
the collection is of type IndexedSeqLike.
Some builder classes
will optimize their representation based on the hint. However,
builder implementations are still required to work correctly even if the hint is
wrong, i.e. a different number of elements is added.
the collection which serves as a hint for the result's size.
Gives a hint how many elements are expected to be added
when the next result is called.
Gives a hint how many elements are expected to be added
when the next result is called. Some builder classes
will optimize their representation based on the hint. However,
builder implementations are still required to work correctly even if the hint is
wrong, i.e. a different number of elements is added.
the hint how many elements will be added.
Gives a hint how many elements are expected to be added
when the next result is called, together with an upper bound
given by the size of some other collection.
Gives a hint how many elements are expected to be added
when the next result is called, together with an upper bound
given by the size of some other collection. Some builder classes
will optimize their representation based on the hint. However,
builder implementations are still required to work correctly even if the hint is
wrong, i.e. a different number of elements is added.
the hint how many elements will be added.
the bounding collection. If it is an IndexedSeqLike, then sizes larger than collection's size are reduced.
Selects an interval of elements.
Selects an interval of elements. The returned 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.
a iterable collection containing the elements greater than or equal to
index from extending up to (but not including) index until
of this iterable collection.
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 number of elements per group
the distance between the first elements of successive groups
An iterator producing iterable collections of size size, except the
last and the only element will be truncated if there are
fewer elements than size.
scala.collection.Iterator, method sliding
Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.) "Sliding window" step is 1 by default.
Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.) "Sliding window" step is 1 by default.
the number of elements per group
An iterator producing iterable collections of size size, except the
last and the only element will be truncated if there are
fewer elements than size.
scala.collection.Iterator, method sliding
Splits this traversable collection into a prefix/suffix pair according to a predicate.
Splits this traversable 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
predicate p does not cause any side-effects.
Note: might return different results for different runs, unless the underlying collection type is ordered.
a pair consisting of the longest prefix of this traversable collection whose
elements all satisfy p, and the rest of this traversable collection.
Splits this traversable collection into two at a given position.
Splits this traversable collection into two 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.
the position at which to split.
a pair of traversable collections consisting of the first n
elements of this traversable collection, and the other elements.
Defines the prefix of this object's toString representation.
Defines the prefix of this object's toString representation.
a string representation which starts the result of toString applied to this map.
Unless overridden in subclasses, the string prefix of every map is "Map".
[use case] Sums up the elements of this collection.
Sums up the elements of this collection.
the sum of all elements in this mutable map of numbers of type Int.
Instead of Int, any other type T with an implicit Numeric[T] implementation
can be used as element type of the mutable map and as result type of sum.
Examples of such types are: Long, Float, Double, BigInt.
Selects all elements except the first.
Selects all elements except the first.
Note: might return different results for different runs, unless the underlying collection type is ordered.
a traversable collection consisting of all elements of this traversable collection except the first one.
`UnsupportedOperationException` if the traversable collection is empty.
Iterates over the tails of this traversable collection.
Iterates over the tails of this traversable collection. The first value will be this
traversable collection and the final one will be an empty traversable collection, with the intervening
values the results of successive applications of tail.
an iterator over all the tails of this traversable collection
List(1,2,3).tails = Iterator(List(1,2,3), List(2,3), List(3), Nil)
Selects first n elements.
Selects first n elements.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the number of elements to take from this iterable collection.
a iterable collection consisting only of the first n elements of this iterable collection,
or else the whole iterable collection, if it has less than n elements.
Selects last n elements.
Selects last n elements.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the number of elements to take
a iterable collection consisting only of the last n elements of this iterable collection, or else the
whole iterable collection, if it has less than n elements.
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.
the longest prefix of this iterable collection whose elements all satisfy
the predicate p.
The underlying collection seen as an instance of Iterable.
The underlying collection seen as an instance of Iterable.
By default this is implemented as the current collection object itself,
but this can be overridden.
[use case] Converts this mutable map into another by copying all elements.
Converts this mutable map into another by copying all elements.
The collection type to build.
a new collection containing all elements of this mutable map.
[use case] Converts this mutable map to an array.
Converts this mutable map to an array.
an array containing all elements of this mutable map.
An ClassTag must be available for the element type of this mutable map.
Uses the contents of this map to create a new mutable buffer.
Uses the contents of this map to create a new mutable buffer.
a buffer containing all elements of this map.
A conversion from collections of type Repr to Iterable objects.
A conversion from collections of type Repr to Iterable objects.
By default this is implemented as just a cast, but this can be overridden.
Converts this traversable or iterator to an indexed sequence.
Converts this traversable or iterator to an indexed sequence.
Note: will not terminate for infinite-sized collections.
an indexed sequence containing all elements of this traversable or iterator.
Returns this iterable collection as an iterable collection.
Returns this iterable collection as an iterable collection.
A new collection will not be built; lazy collections will stay lazy.
Note: will not terminate for infinite-sized collections.
an Iterable containing all elements of this iterable collection.
Returns an Iterator over the elements in this iterable collection.
Returns an Iterator over the elements in this iterable collection. Produces the same
result as iterator.
Note: will not terminate for infinite-sized collections.
an Iterator containing all elements of this iterable collection.
Converts this traversable or iterator to a list.
Converts this traversable or iterator to a list.
Note: will not terminate for infinite-sized collections.
a list containing all elements of this traversable or iterator.
[use case] Converts this mutable map to a map.
Converts this mutable map to a map. This method is unavailable unless the elements are members of Tuple2, each ((T, U)) becoming a key-value pair in the map. Duplicate keys will be overwritten by later keys: if this is an unordered collection, which key is in the resulting map is undefined.
a map of type immutable.Map[T, U]
containing all key/value pairs of type (T, U) of this mutable map.
Converts this map to a sequence.
Converts this map to a sequence. As with toIterable, it's lazy
in this default implementation, as this TraversableOnce may be
lazy and unevaluated.
a sequence containing all elements of this map.
Converts this traversable or iterator to a set.
Converts this traversable or iterator to a set.
Note: will not terminate for infinite-sized collections.
a set containing all elements of this traversable or iterator.
Converts this iterable collection to a stream.
Converts this iterable collection to a stream.
a stream containing all elements of this iterable collection.
Converts this map to a string.
Converts this map to a string.
a string representation of this collection. By default this
string consists of the stringPrefix of this map, followed
by all elements separated by commas and enclosed in parentheses.
Converts this traversable collection to an unspecified Traversable.
Converts this traversable collection to an unspecified Traversable. Will return the same collection if this instance is already Traversable.
Note: will not terminate for infinite-sized collections.
a Traversable containing all elements of this traversable collection.
Converts this traversable or iterator to a Vector.
Converts this traversable or iterator to a Vector.
Note: will not terminate for infinite-sized collections.
a vector containing all elements of this traversable or iterator.
Applies a transformation function to all values contained in this map.
Applies a transformation function to all values contained in this map. The transformation function produces new values from existing keys associated values.
the transformation to apply
the map itself.
Transposes this collection of traversable collections into a collection of collections.
Transposes this collection of traversable collections into a collection of collections.
The resulting collection's type will be guided by the static type of 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))
the type of the elements of each traversable collection.
an implicit conversion which asserts that the
element type of this collection is a Traversable.
a two-dimensional collection of collections which has as nth row the nth column of this collection.
(Changed in version 2.9.0) transpose throws an IllegalArgumentException if collections are not uniformly sized.
IllegalArgumentException if all collections in this collection
are not of the same size.
Converts this collection of pairs into two collections of the first and second half of each pair.
Converts this collection of pairs into two collections of the first and second half of each pair.
val xs = Traversable( (1, "one"), (2, "two"), (3, "three")).unzip // xs == (Traversable(1, 2, 3), // Traversable(one, two, three))
the type of the first half of the element pairs
the type of the second half of the element pairs
an implicit conversion which asserts that the element type of this collection is a pair.
a pair of collections, containing the first, respectively second half of each element pair of this collection.
Converts this collection of triples into three collections of the first, second, and third element of each triple.
Converts this collection of triples into three collections of the first, second, and third element of each triple.
val xs = Traversable( (1, "one", '1'), (2, "two", '2'), (3, "three", '3')).unzip3 // xs == (Traversable(1, 2, 3), // Traversable(one, two, three), // Traversable(1, 2, 3))
the type of the first member of the element triples
the type of the second member of the element triples
the type of the third member of the element triples
an implicit conversion which asserts that the element type of this collection is a triple.
a triple of collections, containing the first, second, respectively third member of each element triple of this collection.
Adds a new key/value pair to this map.
Adds a new key/value pair to this map. If the map already contains a mapping for the key, it will be overridden by the new value.
The key to update
The new value
Creates a new map consisting of all key/value pairs of the current map plus a new pair of a given key and value.
Creates a new map consisting of all key/value pairs of the current map plus a new pair of a given key and value.
the type of the added value
The key to add
The new value
A fresh immutable map with the binding from key to
value added to this map.
Collects all values of this map in an iterable collection.
Collects all values of this map in an iterable collection.
the values of this map as an iterable.
(Changed in version 2.8.0) values returns Iterable[B] rather than Iterator[B].
Creates an iterator for all values in this map.
Creates an iterator for all values in this map.
an iterator over all values that are associated with some key in this map.
Creates a non-strict view of a slice of this iterable collection.
Creates a non-strict view of a slice of this iterable collection.
Note: the difference between view and slice is that view produces
a view of the current iterable collection, whereas slice produces a new iterable collection.
Note: view(from, to) is equivalent to view.slice(from, to)
Note: might return different results for different runs, unless the underlying collection type is ordered.
the index of the first element of the view
the index of the element following the view
a non-strict view of a slice of this iterable collection, starting at index from
and extending up to (but not including) index until.
Creates a non-strict view of this iterable collection.
Creates a non-strict view of this iterable collection.
a non-strict view of this iterable collection.
If these methods aren't overridden to thread through the underlying map, successive calls to withDefault* have no effect.
If these methods aren't overridden to thread through the underlying map, successive calls to withDefault* have no effect.
the function mapping keys to values, used for non-present keys
a wrapper of the map with a default value
The same map with a given default value.
The same map with a given default value.
Invoking transformer methods (e.g. map) will not preserve the default value.
default value used for non-present keys
a wrapper of the map with a default value
Creates a non-strict filter of this traversable collection.
Creates a non-strict filter of this traversable collection.
Note: the difference between c filter p and c withFilter p is that
the former creates a new collection, whereas the latter only
restricts the domain of subsequent map, flatMap, foreach,
and withFilter operations.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the predicate used to test elements.
an object of class WithFilter, which supports
map, flatMap, foreach, and withFilter operations.
All these operations apply to those elements of this traversable collection
which satisfy the predicate p.
[use case] Returns a mutable map formed from this mutable map and another iterable collection by combining corresponding elements in pairs.
Returns a mutable map formed from this mutable map 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.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the type of the second half of the returned pairs
The iterable providing the second half of each result pair
a new mutable map containing pairs consisting of
corresponding elements of this mutable map and that. The length
of the returned collection is the minimum of the lengths of this mutable map and that.
[use case] Returns a mutable map formed from this mutable map and another iterable collection by combining corresponding elements in pairs.
Returns a mutable map formed from this mutable map 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.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the type of the second half of the returned pairs
The iterable providing the second half of each result pair
the element to be used to fill up the result if this mutable map is shorter than that.
the element to be used to fill up the result if that is shorter than this mutable map.
a new mutable map containing pairs consisting of
corresponding elements of this mutable map and that. The length
of the returned collection is the maximum of the lengths of this mutable map and that.
If this mutable map is shorter than that, thisElem values are used to pad the result.
If that is shorter than this mutable map, thatElem values are used to pad the result.
[use case] Zips this mutable map with its indices.
Zips this mutable map with its indices.
Note: might return different results for different runs, unless the underlying collection type is ordered.
A new mutable map containing pairs consisting of all elements of this
mutable map paired with their index. Indices start at 0.
List("a", "b", "c").zipWithIndex = List(("a", 0), ("b", 1), ("c", 2))
(withDefault: any2stringadd[WithDefault[A, B]]).+(other)
(withDefault: MonadOps[(A, B)]).filter(p)
(withDefault: MonadOps[(A, B)]).flatMap(f)
(withDefault: MonadOps[(A, B)]).map(f)
(withDefault: MonadOps[(A, B)]).withFilter(p)