HashMap
final class HashMap[K, +V] extends AbstractMap[K, V] with StrictOptimizedMapOps[K, V, [K, V] =>> HashMap[K, V], HashMap[K, V]] with MapFactoryDefaults[K, V, [K, V] =>> HashMap[K, V], [A] =>> Iterable[A]] with DefaultSerializable
This class implements immutable maps using a Compressed HashArray Mapped Prefixtree.
See paper https://michael.steindorfer.name/publications/oopsla15.pdf for more details.
Type members
Inherited classlikes
Value members
Methods
Merges this HashMap with an other HashMap by combining all keyvalue pairs of both maps, and delegating to a merge
function to resolve any key collisions between the two HashMaps.
 Value Params
 mergef

the merge function which resolves collisions between the two HashMaps. If
mergef
is null, then keys fromthis
will overwrite keys fromthat
, making the behaviour equivalent tothat.concat(this)
 that

the HashMap to merge this HashMap with
 Note
 In cases where
mergef
returns keys which themselves collide with other keys returned bymerge
, or found inthis
orthat
, it is not defined which value will be chosen. For example: Colliding multiple results of merging:// key `3` collides between a result of merging keys `1` and `2` val left = HashMap(1 > 1, 2 > 2) val right = HashMap(1 > 1, 2 > 2) val merged = left.merged(right){ case (_, (_, v1)) => 3 > v1 } // HashMap(3 > 2) is returned, but it could also have returned HashMap(3 > 1)
Colliding results of merging with other keys:// key `2` collides between a result of merging `1`, and existing key `2` val left = HashMap(1 > 1, 2 > 1) val right = HashMap(1 > 2) val merged = left.merged(right)((_,_) => 2 > 3) // HashMap(2 > 1) is returned, but it could also have returned HashMap(2 > 3)
 Example
val left = HashMap(1 > 1, 2 > 1) val right = HashMap(2 > 2, 3 > 2) val merged = left.merged(right){ case ((k0, v0), (k1, v1)) => (k0 + k1) > (v0 + v1) } // HashMap(1 > 1, 3 > 2, 4 > 3)
 Source
 (source)
Inherited methods
Optionally applies a binary operator to all elements of this collection, going
right to left.
Note: will not terminate for infinitesized collections.
Note: might return different results for different runs, unless the
underlying collection type is ordered or the operator is associative
and commutative.
 Type Params
 B

the result type of the binary operator.
 Value Params
 op

the binary operator.
 Returns

an option value containing the result of
reduceRight(op)
if this collection is nonempty,None
otherwise.  Inhertied from
 IterableOnceOps
 Source
 (source)
Composes this partial function with an action function which
gets applied to results of this partial function.
The action function is invoked only for its side effects; its result is ignored.
Note that expression
pf.runWith(action)(x)
is equivalent toif(pf isDefinedAt x) { action(pf(x)); true } else false
except that
runWith
is implemented via applyOrElse
and thus potentially more efficient.
Using runWith
avoids double evaluation of pattern matchers and guards for partial function literals. Value Params
 action

the action function
 Returns

a function which maps arguments
x
toisDefinedAt(x)
. The resulting function runsaction(this(x))
wherethis
is defined.  See also
applyOrElse
. Inhertied from
 PartialFunction
 Source
 (source)
@throws(scala.throws.$lessinit$greater$default$1[scala.NoSuchElementException])
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.
 Value Params
 key

the given key value for which a binding is missing.
 Throws
 NoSuchElementException
 NoSuchElementException
 Inhertied from
 MapOps
 Source
 (source)
@deprecated("Use foldLeft instead of /:", "2.13.0") @inline
 Inhertied from
 IterableOnceOps
 Source
 (source)
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 infinitesized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered.
 Value Params
 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
Seq("a", 1, 5L).collectFirst({ case x: Int => x*10 }) = Some(10)
 Inhertied from
 IterableOnceOps
 Source
 (source)
Partitions this iterable collection into a map of iterable collections according to a discriminator function
key
.
Each element in a group is transformed into a value of type B
using the value
function.It is equivalent to
groupBy(key).mapValues(_.map(f))
, but more efficient.case class User(name: String, age: Int)
def namesByAge(users: Seq[User]): Map[Int, Seq[String]] =
users.groupMap(_.age)(_.name)
Note: Even when applied to a view or a lazy collection it will always force the elements.
 Type Params
 B

the type of values returned by the transformation function
 K

the type of keys returned by the discriminator function
 Value Params
 f

the element transformation function
 key

the discriminator function
 Inhertied from
 IterableOps
 Source
 (source)
The same map with a given default function.
Note: The default is only used for
apply
. Other methods like get
, contains
, iterator
, keys
, etc.
are not affected by withDefault
.@deprecated("Use .to(LazyList) instead of .toStream", "2.13.0") @inline
 Inhertied from
 IterableOnceOps
 Source
 (source)
@deprecated("Use  with an explicit collection", "2.13.0")
Sums up the elements of this collection.
Note: will not terminate for infinitesized collections.
 Type Params
 B

the result type of the
+
operator.
 Value Params
 num

an implicit parameter defining a set of numeric operations which includes the
+
operator to be used in forming the sum.
 Returns

the sum of all elements of this collection with respect to the
+
operator innum
.  Inhertied from
 IterableOnceOps
 Source
 (source)
Tests whether every element of this collection's iterator relates to the
corresponding element of another collection by satisfying a test predicate.
Note: will not terminate for infinitesized collections.
 Type Params
 B

the type of the elements of
that
 Value Params
 p

the test predicate, which relates elements from both collections
 that

the other collection
 Returns

true
if both collections have the same length andp(x, y)
istrue
for all corresponding elementsx
of this iterator andy
ofthat
, otherwisefalse
 Inhertied from
 IterableOnceOps
 Source
 (source)
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 infinitesized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered.
Note: Even when applied to a view or a lazy collection it will always force the elements.
Example:
List(1, 2, 3, 4).scanRight(0)(_ + _) == List(10, 9, 7, 4, 0)
 Type Params
 B

the type of the elements in the resulting collection
 Value Params
 op

the binary operator applied to the intermediate result and the element
 z

the initial value
 Returns

collection with intermediate results
 Inhertied from
 IterableOps
 Source
 (source)
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 infinitesized collections.
 Type Params
 A1

a type parameter for the binary operator, a supertype of
A
.
 Value Params
 op

a binary operator that must be associative.
 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).
 Returns

the result of applying the fold operator
op
between all the elements andz
, orz
if this collection is empty.  Inhertied from
 IterableOnceOps
 Source
 (source)
@deprecated("Iterable.seq always returns the iterable itself", "2.13.0")
Finds the first element which yields the smallest value measured by function f.
Note: will not terminate for infinitesized collections.
 Type Params
 B

The result type of the function f.
 Value Params
 cmp

An ordering to be used for comparing elements.
 f

The measuring function.
 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
.  Inhertied from
 IterableOnceOps
 Source
 (source)
Convert collection to array.
Implementation note: DO NOT call Array.from from this method.
 Inhertied from
 IterableOnceOps
 Source
 (source)
Iterates over the inits of this iterable collection. The first value will be this
iterable collection and the final one will be an empty iterable collection, with the intervening
values the results of successive applications of
init
. Note: Even when applied to a view or a lazy collection it will always force the elements.
 Returns

an iterator over all the inits of this iterable collection
 Example
List(1,2,3).inits = Iterator(List(1,2,3), List(1,2), List(1), Nil)
 Inhertied from
 IterableOps
 Source
 (source)
Groups elements in fixed size blocks by passing a "sliding window"
over them (as opposed to partitioning them, as is done in grouped.)
The returned iterator will be empty when called on an empty collection.
The last element the iterator produces may be smaller than the window
size when the original collection isn't exhausted by the window before
it and its last element isn't skipped by the step before it.
 Value Params
 size

the number of elements per group
 step

the distance between the first elements of successive groups
 Returns

An iterator producing iterable collections of size
size
, except the last element (which may be the only element) will be smaller if there are fewer thansize
elements remaining to be grouped.  See also
 scala.collection.Iterator, method
sliding
 Example
List(1, 2, 3, 4, 5).sliding(2, 2) = Iterator(List(1, 2), List(3, 4), List(5))
List(1, 2, 3, 4, 5, 6).sliding(2, 3) = Iterator(List(1, 2), List(4, 5))
 Inhertied from
 IterableOps
 Source
 (source)
Groups elements in fixed size blocks by passing a "sliding window"
over them (as opposed to partitioning them, as is done in
grouped
.)An empty collection returns an empty iterator, and a nonempty
collection containing fewer elements than the window size returns
an iterator that will produce the original collection as its only
element.
 Value Params
 size

the number of elements per group
 Returns

An iterator producing iterable collections of size
size
, except for a nonempty collection with less thansize
elements, which returns an iterator that produces the source collection itself as its only element.  See also
 scala.collection.Iterator, method
sliding
 Example
List().sliding(2) = empty iterator
List(1).sliding(2) = Iterator(List(1))
List(1, 2).sliding(2) = Iterator(List(1, 2))
List(1, 2, 3).sliding(2) = Iterator(List(1, 2), List(2, 3))
 Inhertied from
 IterableOps
 Source
 (source)
@deprecated("`aggregate` is not relevant for sequential collections. Use `foldLeft(z)(seqop)` instead.", "2.13.0")
 Inhertied from
 IterableOnceOps
 Source
 (source)
Transposes this iterable collection of iterable collections into
a iterable collection of iterable collections.
The resulting collection's type will be guided by the
static type of iterable collection. For example:
val xs = List(
Set(1, 2, 3),
Set(4, 5, 6)).transpose
// xs == List(
// List(1, 4),
// List(2, 5),
// List(3, 6))
val ys = Vector(
List(1, 2, 3),
List(4, 5, 6)).transpose
// ys == Vector(
// Vector(1, 4),
// Vector(2, 5),
// Vector(3, 6))
Note: Even when applied to a view or a lazy collection it will always force the elements.
 Type Params
 B

the type of the elements of each iterable collection.
 Value Params
 asIterable

an implicit conversion which asserts that the element type of this iterable collection is an
Iterable
.
 Returns

a twodimensional iterable collection of iterable collections which has as nth row the nth column of this iterable collection.
 Throws
 IllegalArgumentException
 IllegalArgumentException
 Inhertied from
 IterableOps
 Source
 (source)
Applies a binary operator to a start value and all elements of this collection,
going left to right.
Note: will not terminate for infinitesized collections.
Note: might return different results for different runs, unless the
underlying collection type is ordered or the operator is associative
and commutative.
 Type Params
 B

the result type of the binary operator.
 Value Params
 op

the binary operator.
 z

the start value.
 Returns

the result of inserting
op
between consecutive elements of this collection, going left to right with the start valuez
on the left:op(...op(z, x1), x2, ..., xn)
wherex1, ..., xn
are the elements of this collection. Returnsz
if this collection is empty.  Inhertied from
 IterableOnceOps
 Source
 (source)
Tries to extract a
B
from an A
in a pattern matching expression. Inhertied from
 PartialFunction
 Source
 (source)
override def withFilter(p: (K, V) => Boolean): WithFilter[K, V, [A] =>> Iterable[A], [K, V] =>> HashMap[K, V]]
 Definition Classes
 Inhertied from
 MapFactoryDefaults
 Source
 (source)
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
 Value Params
 b

the string builder to which elements are appended.
 Returns

the string builder
b
to which elements were appended.  Inhertied from
 IterableOnceOps
 Source
 (source)
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
 Value Params
 b

the string builder to which elements are appended.
 sep

the separator string.
 Returns

the string builder
b
to which elements were appended.  Inhertied from
 IterableOnceOps
 Source
 (source)
Turns this partial function into a plain function returning an
Option
result. Returns

a function that takes an argument
x
toSome(this(x))
ifthis
is defined forx
, and toNone
otherwise.  See also
 Function.unlift
 Inhertied from
 PartialFunction
 Source
 (source)
@deprecated("Use toIterable instead", "2.13.0")
Converts this iterable collection to an unspecified Iterable. Will return
the same collection if this instance is already Iterable.
 Returns

An Iterable containing all elements of this iterable collection.
 Inhertied from
 IterableOps
 Source
 (source)
Applies a binary operator to all elements of this collection and a start value,
going right to left.
Note: will not terminate for infinitesized collections.
Note: might return different results for different runs, unless the
underlying collection type is ordered or the operator is associative
and commutative.
 Type Params
 B

the result type of the binary operator.
 Value Params
 op

the binary operator.
 z

the start value.
 Returns

the result of inserting
op
between consecutive elements of this collection, going right to left with the start valuez
on the right:op(x1, op(x2, ... op(xn, z)...))
wherex1, ..., xn
are the elements of this collection. Returnsz
if this collection is empty.  Inhertied from
 IterableOnceOps
 Source
 (source)
 Returns

This collection as a
Seq[A]
. This is equivalent toto(Seq)
but might be faster.  Inhertied from
 IterableOnceOps
 Source
 (source)
Finds the first element which yields the smallest value measured by function f.
Note: will not terminate for infinitesized collections.
 Type Params
 B

The result type of the function f.
 Value Params
 cmp

An ordering to be used for comparing elements.
 f

The measuring function.
 Returns

the first element of this collection with the smallest value measured by function f with respect to the ordering
cmp
.  Throws
 UnsupportedOperationException
 UnsupportedOperationException
 Inhertied from
 IterableOnceOps
 Source
 (source)
@deprecatedOverriding("nonEmpty is defined as !isEmpty; override isEmpty instead", "2.13.0")
Tests whether the collection is not empty.
 Returns

true
if the collection contains at least one element,false
otherwise.  Inhertied from
 IterableOnceOps
 Source
 (source)
@deprecated("Use .view.mapValues(f). A future version will include a strict version of this method (for now, .view.mapValues(f).toMap).", "2.13.0")
Transforms this map by applying a function to every retrieved value.
@deprecated("Check .knownSize instead of .hasDefiniteSize for more actionable information (see scaladoc for details)", "2.13.0")
Tests whether this collection is known to have a finite size.
All strict collections are known to have finite size. For a nonstrict
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. Nonempty 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
welldefined and nontermination is not a concern.
 Returns

true
if this collection is known to have finite size,false
otherwise.  See also
 method
knownSize
for a more useful alternative  Inhertied from
 IterableOnceOps
 Source
 (source)
Composes another partial function
k
with this partial function so that this
partial function gets applied to results of k
.Note that calling isDefinedAt on the resulting partial function may apply the first
partial function and execute its side effect. It is highly recommended to call applyOrElse
instead of isDefinedAt / apply for efficiency.
 Type Params
 R

the parameter type of the transformation function.
 Value Params
 k

the transformation function
 Returns

a partial function with the domain of other partial function narrowed by this partial function, which maps arguments
x
tothis(k(x))
.  Inhertied from
 PartialFunction
 Source
 (source)
Compares the size of this iterable collection to the size of another
Iterable
.
 Value Params
 that

the
Iterable
whose size is compared with this iterable collection's size.
 Returns

A value
x
wherex < 0 if this.size < that.size x == 0 if this.size == that.size x > 0 if this.size > that.size
The method as implemented here does not callsize
directly; its running time isO(this.size min that.size)
instead ofO(this.size + that.size)
. The method should be overridden if computingsize
is cheap andknownSize
returns1
.  Inhertied from
 IterableOps
 Source
 (source)
Compares the size of this iterable collection to a test value.
 Value Params
 otherSize

the test value that gets compared with the size.
 Returns

A value
x
wherex < 0 if this.size < otherSize x == 0 if this.size == otherSize x > 0 if this.size > otherSize
The method as implemented here does not callsize
directly; its running time isO(size min otherSize)
instead ofO(size)
. The method should be overridden if computingsize
is cheap andknownSize
returns1
.  See also
 Inhertied from
 IterableOps
 Source
 (source)
@deprecated("Use ++ with an explicit collection argument instead of + with varargs", "2.13.0")
 Definition Classes
 Inhertied from
 StrictOptimizedMapOps
 Source
 (source)
Analogous to
zip
except that the elements in each collection are not consumed until a strict operation is
invoked on the returned LazyZip2
decorator.Calls to
lazyZip
can be chained to support higher arities (up to 4) without incurring the expense of
constructing and deconstructing intermediary tuples.val xs = List(1, 2, 3)
val res = (xs lazyZip xs lazyZip xs lazyZip xs).map((a, b, c, d) => a + b + c + d)
// res == List(4, 8, 12)
 Type Params
 B

the type of the second element in each eventual pair
 Value Params
 that

the iterable providing the second element of each eventual pair
 Returns

a decorator
LazyZip2
that allows strict operations to be performed on the lazily evaluated pairs or chained calls tolazyZip
. Implicit conversion toIterable[(A, B)]
is also supported.  Inhertied from
 Iterable
 Source
 (source)
Applies a binary operator to all elements of this collection, going right to left.
Note: will not terminate for infinitesized collections.
Note: might return different results for different runs, unless the
underlying collection type is ordered or the operator is associative
and commutative.
 Type Params
 B

the result type of the binary operator.
 Value Params
 op

the binary operator.
 Returns

the result of inserting
op
between consecutive elements of this collection, going right to left:op(x1, op(x2, ..., op(xn1, xn)...))
wherex1, ..., xn
are the elements of this collection.  Throws
 UnsupportedOperationException
 UnsupportedOperationException
 Inhertied from
 IterableOnceOps
 Source
 (source)
The same map with a given default value.
Note: The default is only used for
apply
. Other methods like get
, contains
, iterator
, keys
, etc.
are not affected by withDefaultValue
.Finds the smallest element.
Note: will not terminate for infinitesized collections.
 Type Params
 B

The type over which the ordering is defined.
 Value Params
 ord

An ordering to be used for comparing elements.
 Returns

the smallest element of this collection with respect to the ordering
ord
.  Throws
 UnsupportedOperationException
 UnsupportedOperationException
 Inhertied from
 IterableOnceOps
 Source
 (source)
@deprecated("Use `dest ++= coll` instead", "2.13.0") @inline
 Inhertied from
 IterableOnceOps
 Source
 (source)
Finds the first element which yields the largest value measured by function f.
Note: will not terminate for infinitesized collections.
 Type Params
 B

The result type of the function f.
 Value Params
 cmp

An ordering to be used for comparing elements.
 f

The measuring function.
 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
.  Inhertied from
 IterableOnceOps
 Source
 (source)
Partitions this iterable collection into a map of iterable collections according to some discriminator function.
Note: Even when applied to a view or a lazy collection it will always force the elements.
 Type Params
 K

the type of keys returned by the discriminator function.
 Value Params
 f

the discriminator function.
 Returns

A map from keys to iterable collections such that the following invariant holds:
(xs groupBy f)(k) = xs filter (x => f(x) == k)
That is, every keyk
is bound to a iterable collection of those elementsx
for whichf(x)
equalsk
.  Inhertied from
 IterableOps
 Source
 (source)
@deprecated("Use .iterator instead of .toIterator", "2.13.0") @inline
 Inhertied from
 IterableOnceOps
 Source
 (source)
Finds the first element of the collection satisfying a predicate, if any.
Note: may not terminate for infinitesized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered.
 Value Params
 p

the predicate used to test elements.
 Returns

an option value containing the first element in the collection that satisfies
p
, orNone
if none exists.  Inhertied from
 IterableOnceOps
 Source
 (source)
@deprecated("Use iterableFactory instead", "2.13.0") @deprecatedOverriding("Use iterableFactory instead", "2.13.0") @inline
 Inhertied from
 IterableOps
 Source
 (source)
Finds the first element which yields the largest value measured by function f.
Note: will not terminate for infinitesized collections.
 Type Params
 B

The result type of the function f.
 Value Params
 cmp

An ordering to be used for comparing elements.
 f

The measuring function.
 Returns

the first element of this collection with the largest value measured by function f with respect to the ordering
cmp
.  Throws
 UnsupportedOperationException
 UnsupportedOperationException
 Inhertied from
 IterableOnceOps
 Source
 (source)
Composes this partial function with another partial function that
gets applied to results of this partial function.
Note that calling isDefinedAt on the resulting partial function may apply the first
partial function and execute its side effect. It is highly recommended to call applyOrElse
instead of isDefinedAt / apply for efficiency.
 Type Params
 C

the result type of the transformation function.
 Value Params
 k

the transformation function
 Returns

a partial function with the domain of this partial function narrowed by other partial function, which maps arguments
x
tok(this(x))
.  Inhertied from
 PartialFunction
 Source
 (source)
Composes this partial function with a transformation function that
gets applied to results of this partial function.
If the runtime type of the function is a
PartialFunction
then the
other andThen
method is used (note its cautions).
 Type Params
 C

the result type of the transformation function.
 Value Params
 k

the transformation function
 Returns

a partial function with the domain of this partial function, possibly narrowed by the specified function, which maps arguments
x
tok(this(x))
.  Definition Classes
 Inhertied from
 PartialFunction
 Source
 (source)
Partitions elements in fixed size iterable collections.
 Value Params
 size

the number of elements per group
 Returns

An iterator producing iterable collections of size
size
, except the last will be less than sizesize
if the elements don't divide evenly.  See also
 scala.collection.Iterator, method
grouped
 Inhertied from
 IterableOps
 Source
 (source)
Finds the largest element.
Note: will not terminate for infinitesized collections.
 Type Params
 B

The type over which the ordering is defined.
 Value Params
 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
.  Inhertied from
 IterableOnceOps
 Source
 (source)
Multiplies up the elements of this collection.
Note: will not terminate for infinitesized collections.
 Type Params
 B

the result type of the
*
operator.
 Value Params
 num

an implicit parameter defining a set of numeric operations which includes the
*
operator to be used in forming the product.
 Returns

the product of all elements of this collection with respect to the
*
operator innum
.  Inhertied from
 IterableOnceOps
 Source
 (source)
Composes this partial function with a fallback partial function which
gets applied where this partial function is not defined.
 Type Params
 A1

the argument type of the fallback function
 B1

the result type of the fallback function
 Value Params
 that

the fallback function
 Returns

a partial function which has as domain the union of the domains of this partial function and
that
. The resulting partial function takesx
tothis(x)
wherethis
is defined, and tothat(x)
where it is not.  Inhertied from
 PartialFunction
 Source
 (source)
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]
 Inhertied from
 IterableOnceOps
 Source
 (source)
Computes a prefix scan of the elements of the collection.
Note: The neutral element
z
may be applied more than once.
 Type Params
 B

element type of the resulting collection
 Value Params
 op

the associative operator for the scan
 z

neutral element for the operator
op
 Returns

a new iterable collection containing the prefix scan of the elements in this iterable collection
 Inhertied from
 IterableOps
 Source
 (source)
Optionally selects the first element.
Note: might return different results for different runs, unless the underlying collection type is ordered.
 Returns

the first element of this iterable collection if it is nonempty,
None
if it is empty.  Inhertied from
 IterableOps
 Source
 (source)
Tests whether a predicate holds for all elements of this collection.
Note: may not terminate for infinitesized collections.
 Value Params
 p

the predicate used to test elements.
 Returns

true
if this collection is empty or the given predicatep
holds for all elements of this collection, otherwisefalse
.  Inhertied from
 IterableOnceOps
 Source
 (source)
@deprecated("Use foldRight instead of :\\", "2.13.0") @inline
 Inhertied from
 IterableOnceOps
 Source
 (source)
Alias for
concat
 Inhertied from
 IterableOps
 Source
 (source)
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.
 Type Params
 B

the type of the elements of the array.
 Value Params
 len

the maximal number of elements to copy.
 start

the starting index of xs.
 xs

the array to fill.
 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.
 Inhertied from
 IterableOnceOps
 Source
 (source)
@deprecatedOverriding("This should always forward to the 3arg version of this method", since = "2.13.4")
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.
 Type Params
 B

the type of the elements of the array.
 Value Params
 start

the starting index of xs.
 xs

the array to fill.
 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.
 Inhertied from
 IterableOnceOps
 Source
 (source)
@deprecatedOverriding("This should always forward to the 3arg version of this method", since = "2.13.4")
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.
 Type Params
 B

the type of the elements of the array.
 Value Params
 xs

the array to fill.
 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.
 Inhertied from
 IterableOnceOps
 Source
 (source)
Finds the smallest element.
Note: will not terminate for infinitesized collections.
 Type Params
 B

The type over which the ordering is defined.
 Value Params
 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
.  Inhertied from
 IterableOnceOps
 Source
 (source)
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.  Inhertied from
 IterableOnceOps
 Source
 (source)
Displays all elements of this collection in a string using a separator string.
Delegates to addString, which can be overridden.
 Value Params
 sep

the separator string.
 Returns

a string representation of this collection. In the resulting string the string representations (w.r.t. the method
toString
) of all elements of this collection are separated by the stringsep
.  Example
List(1, 2, 3).mkString("") = "123"
 Inhertied from
 IterableOnceOps
 Source
 (source)
Displays all elements of this collection in a string using start, end, and
separator strings.
Delegates to addString, which can be overridden.
 Value Params
 end

the ending string.
 sep

the separator string.
 start

the starting string.
 Returns

a string representation of this collection. The resulting string begins with the string
start
and ends with the stringend
. Inside, the string representations (w.r.t. the methodtoString
) of all elements of this collection are separated by the stringsep
.  Example
List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"
 Inhertied from
 IterableOnceOps
 Source
 (source)
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.
 Type Params
 B

A type parameter for the binary operator, a supertype of
A
.
 Value Params
 op

A binary operator that must be associative.
 Returns

An option value containing result of applying reduce operator
op
between all the elements if the collection is nonempty, andNone
otherwise.  Inhertied from
 IterableOnceOps
 Source
 (source)
Partitions this iterable collection into a map according to a discriminator function
key
. All the values that
have the same discriminator are then transformed by the f
function and then reduced into a
single value with the reduce
function.It is equivalent to
groupBy(key).mapValues(_.map(f).reduce(reduce))
, but more efficient.def occurrences[A](as: Seq[A]): Map[A, Int] =
as.groupMapReduce(identity)(_ => 1)(_ + _)
Note: Even when applied to a view or a lazy collection it will always force the elements.
 Inhertied from
 IterableOps
 Source
 (source)
Counts the number of elements in the collection which satisfy a predicate.
Note: will not terminate for infinitesized collections.
 Value Params
 p

the predicate used to test elements.
 Returns

the number of elements satisfying the predicate
p
.  Inhertied from
 IterableOnceOps
 Source
 (source)
Returns a new iterable collection containing the elements from the left hand operand followed by the elements from the
right hand operand. The element type of the iterable collection is the most specific superclass encompassing
the element types of the two operands.
 Type Params
 B

the element type of the returned collection.
 Value Params
 suffix

the traversable to append.
 Returns

a new iterable collection which contains all elements of this iterable collection followed by all elements of
suffix
.  Inhertied from
 IterableOps
 Source
 (source)
Returns a value class containing operations for comparing the size of this iterable collection to a test value.
These operations are implemented in terms of
sizeCompare(Int)
, and
allow the following more readable usages:this.sizeIs < size // this.sizeCompare(size) < 0
this.sizeIs <= size // this.sizeCompare(size) <= 0
this.sizeIs == size // this.sizeCompare(size) == 0
this.sizeIs != size // this.sizeCompare(size) != 0
this.sizeIs >= size // this.sizeCompare(size) >= 0
this.sizeIs > size // this.sizeCompare(size) > 0
 Inhertied from
 IterableOps
 Source
 (source)
@deprecated("Use .view.filterKeys(f). A future version will include a strict version of this method (for now, .view.filterKeys(p).toMap).", "2.13.0")
Filters this map by retaining only keys satisfying a predicate.
@deprecated("Use coll instead of repr in a collection implementation, use the collection value itself from the outside", "2.13.0")
 Inhertied from
 IterableOps
 Source
 (source)
Applies a binary operator to all elements of this collection,
going left to right.
Note: will not terminate for infinitesized collections.
Note: might return different results for different runs, unless the
underlying collection type is ordered or the operator is associative
and commutative.
 Type Params
 B

the result type of the binary operator.
 Value Params
 op

the binary operator.
 Returns

the result of inserting
op
between consecutive elements of this collection, going left to right:op( op( ... op(x1, x2) ..., xn1), xn)
wherex1, ..., xn
are the elements of this collection.  Throws
 UnsupportedOperationException
 UnsupportedOperationException
 Inhertied from
 IterableOnceOps
 Source
 (source)
Tests whether a predicate holds for at least one element of this collection.
Note: may not terminate for infinitesized collections.
 Value Params
 p

the predicate used to test elements.
 Returns

true
if the given predicatep
is satisfied by at least one element of this collection, otherwisefalse
 Inhertied from
 IterableOnceOps
 Source
 (source)
override def unzip3[A1, A2, A3](asTriple: (K, V) => (A1, A2, A3)): (Iterable[A1], Iterable[A2], Iterable[A3])
 Definition Classes
 Inhertied from
 StrictOptimizedIterableOps
 Source
 (source)
Returns a iterable collection formed from this iterable collection and another iterable collection
by combining corresponding elements in pairs.
If one of the two collections is shorter than the other,
placeholder elements are used to extend the shorter collection to the length of the longer.
 Value Params
 that

the iterable providing the second half of each result pair
 thatElem

the element to be used to fill up the result if
that
is shorter than this iterable collection.  thisElem

the element to be used to fill up the result if this iterable collection is shorter than
that
.
 Returns

a new collection of type
That
containing pairs consisting of corresponding elements of this iterable collection andthat
. The length of the returned collection is the maximum of the lengths of this iterable collection andthat
. If this iterable collection is shorter thanthat
,thisElem
values are used to pad the result. Ifthat
is shorter than this iterable collection,thatElem
values are used to pad the result.  Inhertied from
 IterableOps
 Source
 (source)
Returns an extractor object with a
unapplySeq
method, which extracts each element of a sequence data.
 Example
val firstChar: String => Option[Char] = _.headOption Seq("foo", "bar", "baz") match { case firstChar.unlift.elementWise(c0, c1, c2) => println(s"$c0, $c1, $c2") // Output: f, b, b }
 Inhertied from
 PartialFunction
 Source
 (source)
Finds the largest element.
Note: will not terminate for infinitesized collections.
 Type Params
 B

The type over which the ordering is defined.
 Value Params
 ord

An ordering to be used for comparing elements.
 Returns

the largest element of this collection with respect to the ordering
ord
.  Throws
 UnsupportedOperationException
 UnsupportedOperationException
 Inhertied from
 IterableOnceOps
 Source
 (source)
@deprecated("Use ++ instead of ++: for collections of type Iterable", "2.13.0")
 Inhertied from
 IterableOps
 Source
 (source)
@deprecated("Use ++ instead of ++: for collections of type Iterable", "2.13.0")
@deprecated("Use .view.slice(from, until) instead of .view(from, until)", "2.13.0")
A view over a slice of the elements of this collection.
 Inhertied from
 IterableOps
 Source
 (source)
Optionally applies a binary operator to all elements of this collection, going left to right.
Note: will not terminate for infinitesized collections.
Note: might return different results for different runs, unless the
underlying collection type is ordered or the operator is associative
and commutative.
 Type Params
 B

the result type of the binary operator.
 Value Params
 op

the binary operator.
 Returns

an option value containing the result of
reduceLeft(op)
if this collection is nonempty,None
otherwise.  Inhertied from
 IterableOnceOps
 Source
 (source)
Iterates over the tails of this iterable collection. The first value will be this
iterable collection and the final one will be an empty iterable collection, with the intervening
values the results of successive applications of
tail
.
 Returns

an iterator over all the tails of this iterable collection
 Example
List(1,2,3).tails = Iterator(List(1,2,3), List(2,3), List(3), Nil)
 Inhertied from
 IterableOps
 Source
 (source)
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.
 Type Params
 B

A type parameter for the binary operator, a supertype of
A
.
 Value Params
 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.  Throws
 UnsupportedOperationException
 UnsupportedOperationException
 Inhertied from
 IterableOnceOps
 Source
 (source)
Optionally selects the last element.
Note: might return different results for different runs, unless the underlying collection type is ordered.
 Returns

the last element of this iterable collection$ if it is nonempty,
None
if it is empty.  Inhertied from
 IterableOps
 Source
 (source)