IterableOnceOps

trait IterableOnceOps[+A, +CC[_], +C] extends Any

This implementation trait can be mixed into an IterableOnce to get the basic methods that are shared between Iterator and Iterable. The IterableOnce must support multiple calls to iterator but may or may not return the same Iterator every time.

Self Type: IterableOnceOps[A, CC, C] with IterableOnce[A]
Source: IterableOnce.scala

Linear Supertypes

Any

Known Subclasses

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IterableOnceOps
Any

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by any2stringadd
by StringFormat
by Ensuring
by ArrowAssoc

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Abstract Value Members

abstract def collect[B](pf: PartialFunction[A, B]): CC[B]
Builds a new collection by applying a partial function to all elements of this collection on which the function is defined.
Builds a new collection by applying a partial function to all elements of this collection on which the function is defined.
B
the element type of the returned collection.
pf
the partial function which filters and maps the collection.
returns
a new 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.
Note
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.
abstract def drop(n: Int): C
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 collection.
returns
a collection consisting of all elements of this collection except the first n ones, or else the empty collection, if this collection has less than n elements. If n is negative, don't drop any elements.
Note
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.
abstract def dropWhile(p: (A) => Boolean): C
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 collection whose first element does not satisfy the predicate p.
Note
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.
abstract def filter(p: (A) => Boolean): C
Selects all elements of this collection which satisfy a predicate.
Selects all elements of this collection which satisfy a predicate.
p
the predicate used to test elements.
returns
a new iterator consisting of all elements of this collection that satisfy the given predicate p. The order of the elements is preserved.
abstract def filterNot(pred: (A) => Boolean): C
Selects all elements of this collection which do not satisfy a predicate.
Selects all elements of this collection which do not satisfy a predicate.
pred
the predicate used to test elements.
returns
a new collection consisting of all elements of this collection that do not satisfy the given predicate pred. Their order may not be preserved.
abstract def flatMap[B](f: (A) => IterableOnce[B]): CC[B]
Builds a new collection by applying a function to all elements of this collection and using the elements of the resulting collections.
Builds a new collection by applying a function to all elements of this 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 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 collection resulting from applying the given collection-valued function f to each element of this collection and concatenating the results.
Note
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.
abstract def flatten[B](implicit asIterable: (A) => IterableOnce[B]): CC[B]
Converts this collection of traversable collections into a collection formed by the elements of these traversable collections.
Converts this collection of traversable collections into a collection formed by the elements of these traversable collections.
The resulting collection's type will be guided by the type of 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.
asIterable
an implicit conversion which asserts that the element type of this collection is a GenTraversable.
returns
a new collection resulting from concatenating all element collections.
Note
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.
abstract def getClass(): Class[_ <: AnyRef]
Returns the runtime class representation of the object.
Returns the runtime class representation of the object.
returns
a class object corresponding to the runtime type of the receiver.
Definition Classes
Any
abstract def map[B](f: (A) => B): CC[B]
Builds a new collection by applying a function to all elements of this collection.
Builds a new collection by applying a function to all elements of this collection.
B
the element type of the returned collection.
f
the function to apply to each element.
returns
a new collection resulting from applying the given function f to each element of this collection and collecting the results.
Note
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.
abstract def scanLeft[B](z: B)(op: (B, A) => B): CC[B]
Produces a collection containing cumulative results of applying the operator going left to right, including the initial value.
Produces a 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
Note
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.
abstract def slice(from: Int, until: Int): C
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.
from
the lowest index to include from this collection.
until
the lowest index to EXCLUDE from this collection.
returns
a collection containing the elements greater than or equal to index from extending up to (but not including) index until of this collection.
Note
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.
abstract def span(p: (A) => Boolean): (C, C)
Splits this collection into a prefix/suffix pair according to a predicate.
Splits this 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.
p
the test predicate
returns
a pair consisting of the longest prefix of this collection whose elements all satisfy p, and the rest of this collection.
Note
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterators that were returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterators as well.
abstract def take(n: Int): C
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 collection.
returns
a collection consisting only of the first n elements of this collection, or else the whole collection, if it has less than n elements. If n is negative, returns an empty collection.
Note
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.
abstract def takeWhile(p: (A) => Boolean): C
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 collection whose elements all satisfy the predicate p.
Note
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.
abstract def tapEach[U](f: (A) => U): C
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 apply f 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 collection
returns
The same logical collection as this
abstract def zipWithIndex: CC[(A, Int)]
Zips this collection with its indices.
Zips this collection with its indices.
returns
A new collection containing pairs consisting of all elements of this collection paired with their index. Indices start at 0.
Example:
1. List("a", "b", "c").zipWithIndex == List(("a", 0), ("b", 1), ("c", 2))
Note
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

Concrete Value Members

final def !=(arg0: Any): Boolean
Test two objects for inequality.
Test two objects for inequality.
returns
true if !(this == that), false otherwise.
Definition Classes
Any
final def ##(): Int
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.
returns
a hash value consistent with ==
Definition Classes
Any
def +(other: String): String
Implicit
This member is added by an implicit conversion from IterableOnceOps[A, CC, C] toany2stringadd[IterableOnceOps[A, CC, C]] performed by method any2stringadd in scala.Predef.
Definition Classes
any2stringadd
def ->[B](y: B): (IterableOnceOps[A, CC, C], B)
Implicit
This member is added by an implicit conversion from IterableOnceOps[A, CC, C] toArrowAssoc[IterableOnceOps[A, CC, C]] performed by method ArrowAssoc in scala.Predef.
Definition Classes
ArrowAssoc
Annotations
@inline()
final def ==(arg0: Any): Boolean
Test two objects for equality.
Test two objects for equality. The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).
returns
true if the receiver object is equivalent to the argument; false otherwise.
Definition Classes
Any
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.
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 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
```
b
the string builder to which elements are appended.
sep
the separator string.
returns
the string builder b to which elements were appended.
Annotations
@inline()
def addString(b: mutable.StringBuilder, start: String, sep: String, end: String): mutable.StringBuilder
Appends all elements of this collection to a string builder using start, end, and separator strings.
Appends all elements of this collection 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 (w.r.t. the method toString) of all elements of this collection are 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 , "List(" , ", " , ")")
res5: StringBuilder = List(1, 2, 3, 4)
```
b
the string builder to which elements are appended.
start
the starting string.
sep
the separator string.
end
the ending string.
returns
the string builder b to which elements were appended.
final def asInstanceOf[T0]: T0
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.
returns
the receiver object.
Definition Classes
Any
Exceptions thrown
ClassCastException if the receiver object is not an instance of the erasure of type T0.
def collectFirst[B](pf: PartialFunction[A, 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.
Example:
1. Seq("a", 1, 5L).collectFirst({ case x: Int => x*10 }) = Some(10)
def copyToArray[B >: A](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 index start with at most len 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
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 >: A](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 index start 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.
def copyToArray[B >: A](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 index start 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.
def corresponds[B](that: IterableOnce[B])(p: (A, 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.
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 and p(x, y) is true for all corresponding elements x of this iterator and y of that, otherwise false
def count(p: (A) => 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.
p
the predicate used to test elements.
returns
the number of elements satisfying the predicate p.
def ensuring(cond: (IterableOnceOps[A, CC, C]) => Boolean, msg: => Any): IterableOnceOps[A, CC, C]
Implicit
This member is added by an implicit conversion from IterableOnceOps[A, CC, C] toEnsuring[IterableOnceOps[A, CC, C]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring
def ensuring(cond: (IterableOnceOps[A, CC, C]) => Boolean): IterableOnceOps[A, CC, C]
Implicit
This member is added by an implicit conversion from IterableOnceOps[A, CC, C] toEnsuring[IterableOnceOps[A, CC, C]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring
def ensuring(cond: Boolean, msg: => Any): IterableOnceOps[A, CC, C]
Implicit
This member is added by an implicit conversion from IterableOnceOps[A, CC, C] toEnsuring[IterableOnceOps[A, CC, C]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring
def ensuring(cond: Boolean): IterableOnceOps[A, CC, C]
Implicit
This member is added by an implicit conversion from IterableOnceOps[A, CC, C] toEnsuring[IterableOnceOps[A, CC, C]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring
def equals(arg0: Any): Boolean
Compares the receiver object (this) with the argument object (that) for equivalence.
Compares the receiver object (this) with the argument object (that) for equivalence.
Any implementation of this method should be an equivalence relation:
- It is reflexive: for any instance x of type Any, x.equals(x) should return true.
- It is symmetric: for any instances x and y of type Any, x.equals(y) should return true if and only if y.equals(x) returns true.
- It is transitive: for any instances x, y, and z of type Any if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
If you override this method, you should verify that your implementation remains an equivalence relation. Additionally, when overriding this method it is usually necessary to override hashCode to ensure that objects which are "equal" (o1.equals(o2) returns true) hash to the same scala.Int. (o1.hashCode.equals(o2.hashCode)).
returns
true if the receiver object is equivalent to the argument; false otherwise.
Definition Classes
Any
def exists(p: (A) => Boolean): Boolean
Tests whether a predicate holds for at least one element of this collection.
Tests whether a predicate holds for at least one element of this collection.
Note: may not terminate for infinite-sized collections.
p
the predicate used to test elements.
returns
true if the given predicate p is satisfied by at least one element of this collection, otherwise false
def find(p: (A) => Boolean): Option[A]
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, or None if none exists.
def fold[A1 >: A](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 to foldLeft 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 and z, or z if this collection is empty.
def foldLeft[B](z: B)(op: (B, A) => 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 value z on the left:
```
op(...op(z, x_1), x_2, ..., x_n)
```
where x₁, ..., x_n are the elements of this collection. Returns z if this collection is empty.
def foldRight[B](z: B)(op: (A, 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 value z on the right:
```
op(x_1, op(x_2, ... op(x_n, z)...))
```
where x₁, ..., x_n are the elements of this collection. Returns z if this collection is empty.
def forall(p: (A) => Boolean): Boolean
Tests whether a predicate holds for all elements of this collection.
Tests whether a predicate holds for all elements of this collection.
Note: may not terminate for infinite-sized collections.
p
the predicate used to test elements.
returns
true if this collection is empty or the given predicate p holds for all elements of this collection, otherwise false.
def foreach[U](f: (A) => U): Unit
Apply f to each element for its side effects Note: [U] parameter needed to help scalac's type inference.
def formatted(fmtstr: String): String
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).
Implicit
This member is added by an implicit conversion from IterableOnceOps[A, CC, C] toStringFormat[IterableOnceOps[A, CC, C]] performed by method StringFormat in scala.Predef.
Definition Classes
StringFormat
Annotations
@inline()
def hashCode(): Int
Calculate a hash code value for the object.
Calculate a hash code value for the object.
The default hashing algorithm is platform dependent.
Note that it is allowed for two objects to have identical hash codes (o1.hashCode.equals(o2.hashCode)) yet not be equal (o1.equals(o2) returns false). A degenerate implementation could always return 0. However, it is required that if two objects are equal (o1.equals(o2) returns true) that they have identical hash codes (o1.hashCode.equals(o2.hashCode)). Therefore, when overriding this method, be sure to verify that the behavior is consistent with the equals method.
returns
the hash code value for this object.
Definition Classes
Any
def isEmpty: Boolean
Tests whether the collection is empty.
Tests whether the collection 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 collection contains no elements, false otherwise.
final def isInstanceOf[T0]: Boolean
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.
returns
true if the receiver object is an instance of erasure of type T0; false otherwise.
Definition Classes
Any
def isTraversableAgain: Boolean
Tests whether this collection can be repeatedly traversed.
Tests whether this collection can be repeatedly traversed. Always true for Iterables and false for Iterators unless overridden.
returns
true if it is repeatedly traversable, false otherwise.
def max[B >: A](implicit ord: math.Ordering[B]): A
Finds the largest element.
Finds the largest element.
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.
Exceptions thrown
UnsupportedOperationException if this collection is empty.
def maxBy[B](f: (A) => B)(implicit cmp: math.Ordering[B]): A
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.
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.
Exceptions thrown
UnsupportedOperationException if this collection is empty.
def maxByOption[B](f: (A) => B)(implicit cmp: math.Ordering[B]): Option[A]
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.
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.
def maxOption[B >: A](implicit ord: math.Ordering[B]): Option[A]
Finds the largest element.
Finds the largest element.
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.
def min[B >: A](implicit ord: math.Ordering[B]): A
Finds the smallest element.
Finds the smallest element.
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.
Exceptions thrown
UnsupportedOperationException if this collection is empty.
def minBy[B](f: (A) => B)(implicit cmp: math.Ordering[B]): A
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.
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.
Exceptions thrown
UnsupportedOperationException if this collection is empty.
def minByOption[B](f: (A) => B)(implicit cmp: math.Ordering[B]): Option[A]
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.
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.
def minOption[B >: A](implicit ord: math.Ordering[B]): Option[A]
Finds the smallest element.
Finds the smallest element.
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.
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.
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 string sep.
Annotations
@inline()
Example:
1. List(1, 2, 3).mkString("|") = "1|2|3"
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 string end. Inside, the string representations (w.r.t. the method toString) of all elements of this collection are separated by the string sep.
Example:
1. List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"
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.
Annotations
@deprecatedOverriding("nonEmpty is defined as !isEmpty; override isEmpty instead", "2.13.0")
def product[B >: A](implicit num: math.Numeric[B]): B
Multiplies up the elements of this collection.
Multiplies up the elements of this collection.
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 in num.
def reduce[B >: A](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.
Exceptions thrown
UnsupportedOperationException if this collection is empty.
def reduceLeft[B >: A](op: (B, A) => 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, ..., x_n are the elements of this collection.
Exceptions thrown
UnsupportedOperationException if this collection is empty.
def reduceLeftOption[B >: A](op: (B, A) => 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.
def reduceOption[B >: A](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, and None otherwise.
def reduceRight[B >: A](op: (A, 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, ..., x_n are the elements of this collection.
Exceptions thrown
UnsupportedOperationException if this collection is empty.
def reduceRightOption[B >: A](op: (A, 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.
def reversed: Iterable[A]
Attributes
protected
def size: Int
The size of this collection.
The size of this collection.
Note: will not terminate for infinite-sized collections.
returns
the number of elements in this collection.
def splitAt(n: Int): (C, C)
Splits this collection into a prefix/suffix pair at a given position.
Splits this 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 collections consisting of the first n elements of this collection, and the other elements.
Note
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterators that were returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterators as well.
def sum[B >: A](implicit num: math.Numeric[B]): B
Sums up the elements of this collection.
Sums up the elements of this collection.
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 in num.
def to[C1](factory: Factory[A, C1]): C1
Given a collection factory factory, convert this collection to the appropriate representation for the current element type A.
Given a collection factory factory, convert this collection to the appropriate representation for the current element type A. Example uses:
xs.to(List) xs.to(ArrayBuffer) xs.to(BitSet) // for xs: Iterable[Int]
def toArray[B >: A](implicit arg0: ClassTag[B]): Array[B]
Convert collection to array.
final def toBuffer[B >: A]: Buffer[B]
Annotations
@inline()
def toIndexedSeq: immutable.IndexedSeq[A]
def toList: immutable.List[A]
def toMap[K, V](implicit ev: <:<[A, (K, V)]): immutable.Map[K, V]
def toSeq: immutable.Seq[A]
returns
This collection as a Seq[A]. This is equivalent to to(Seq) but might be faster.
def toSet[B >: A]: immutable.Set[B]
def toString(): String
Returns a string representation of the object.
Returns a string representation of the object.
The default representation is platform dependent.
returns
a string representation of the object.
Definition Classes
Any
def toVector: immutable.Vector[A]

Deprecated Value Members

final def /:[B](z: B)(op: (B, A) => B): B
Annotations
@deprecated @inline()
Deprecated
(Since version 2.13.0) Use foldLeft instead of /:
final def :\[B](z: B)(op: (A, B) => B): B
Annotations
@deprecated @inline()
Deprecated
(Since version 2.13.0) Use foldRight instead of :\
def aggregate[B](z: => B)(seqop: (B, A) => B, combop: (B, B) => B): B
Annotations
@deprecated
Deprecated
(Since version 2.13.0) aggregate is not relevant for sequential collections. Use foldLeft(z)(seqop) instead.
final def copyToBuffer[B >: A](dest: Buffer[B]): Unit
Annotations
@deprecated @inline()
Deprecated
(Since version 2.13.0) Use dest ++= coll 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 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.
returns
true if this collection is known to have finite size, false otherwise.
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
final def toIterator: Iterator[A]
Annotations
@deprecated @inline()
Deprecated
(Since version 2.13.0) Use .iterator instead of .toIterator
final def toStream: immutable.Stream[A]
Annotations
@deprecated @inline()
Deprecated
(Since version 2.13.0) Use .to(LazyList) instead of .toStream
def →[B](y: B): (IterableOnceOps[A, CC, C], B)
Implicit
This member is added by an implicit conversion from IterableOnceOps[A, CC, C] toArrowAssoc[IterableOnceOps[A, CC, C]] performed by method ArrowAssoc in scala.Predef.
Definition Classes
ArrowAssoc
Annotations
@deprecated
Deprecated
(Since version 2.13.0) Use -> instead. If you still wish to display it as one character, consider using a font with programming ligatures such as Fira Code.

Packages

Package structure

Automatic imports

IterableOnceOps

trait IterableOnceOps[+A, +CC[_], +C] extends Any

Abstract Value Members

Concrete Value Members

Deprecated Value Members

Inherited from Any

Inherited by implicit conversion any2stringadd fromIterableOnceOps[A, CC, C] to any2stringadd[IterableOnceOps[A, CC, C]]

Inherited by implicit conversion StringFormat fromIterableOnceOps[A, CC, C] to StringFormat[IterableOnceOps[A, CC, C]]

Inherited by implicit conversion Ensuring fromIterableOnceOps[A, CC, C] to Ensuring[IterableOnceOps[A, CC, C]]

Inherited by implicit conversion ArrowAssoc fromIterableOnceOps[A, CC, C] to ArrowAssoc[IterableOnceOps[A, CC, C]]

Ungrouped

Packages

Package structure

Automatic imports

IterableOnceOps

trait IterableOnceOps[+A, +CC[_], +C] extends Any

Abstract Value Members

Concrete Value Members

Deprecated Value Members

Inherited from Any

Inherited by implicit conversion any2stringadd fromIterableOnceOps[A, CC, C] to any2stringadd[IterableOnceOps[A, CC, C]]

Inherited by implicit conversion StringFormat fromIterableOnceOps[A, CC, C] to StringFormat[IterableOnceOps[A, CC, C]]

Inherited by implicit conversion Ensuring fromIterableOnceOps[A, CC, C] to Ensuring[IterableOnceOps[A, CC, C]]

Inherited by implicit conversion ArrowAssoc fromIterableOnceOps[A, CC, C] to ArrowAssoc[IterableOnceOps[A, CC, C]]

Ungrouped

IterableOnceOps