Scala 3/API/scala.collection.mutable/HashMap

HashMap

@deprecatedInheritance("HashMap will be made final; use .withDefault for the common use case of computing a default value", "2.13.0") class HashMap[K, V](initialCapacity: Int, loadFactor: Double) extends AbstractMap[K, V] with MapOps[K, V, [K, V] =>> HashMap[K, V], HashMap[K, V]] with StrictOptimizedIterableOps[(K, V), [A] =>> Iterable[A], HashMap[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 Serializable
This class implements mutable maps using a hashtable.
Type Params
K
the type of the keys contained in this hash map.
V
the type of the values assigned to keys in this hash map.
See also
"Scala's Collection Library overview" section on Hash Tables for more information.
Companion
object
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trait StrictOptimizedMapOps[K, V, [K, V] =>> HashMap[K, V], HashMap[K, V]]
trait StrictOptimizedIterableOps[(K, V), [A] =>> Iterable[A], HashMap[K, V]]
class AbstractMap[K, V]
trait Map[K, V]
trait MapOps[K, V, [K, V] =>> HashMap[K, V], HashMap[K, V]]
trait Shrinkable[K]
trait Builder[(K, V), HashMap[K, V]]
trait Growable[(K, V)]
trait Clearable
trait Cloneable[HashMap[K, V]]
trait Cloneable
trait Iterable[(K, V)]
class AbstractMap[K, V]
trait Map[K, V]
trait Equals
trait MapFactoryDefaults[K, V, [K, V] =>> HashMap[K, V], [A] =>> Iterable[A]]
trait MapOps[K, V, [K, V] =>> HashMap[K, V], HashMap[K, V]]
trait K => V
class AbstractIterable[(K, V)]
trait Iterable[(K, V)]
trait IterableFactoryDefaults[(K, V), [A] =>> Iterable[A]]
trait IterableOps[(K, V), [A] =>> Iterable[A], HashMap[K, V]]
trait IterableOnceOps[(K, V), [A] =>> Iterable[A], HashMap[K, V]]
trait IterableOnce[(K, V)]
class Object
trait Matchable
class Any

Value members

Constructors

def this()
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Methods

override def size: Int
Definition Classes
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override def contains(key: K): Boolean
Definition Classes
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override def sizeHint(size: Int): Unit
Definition Classes
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override def addAll(xs: IterableOnce[(K, V)]): HashMap[K, V]
Definition Classes
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override def updateWith(key: K)(remappingFunction: Option[V] => Option[V]): Option[V]
Definition Classes
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override def subtractAll(xs: IterableOnce[K]): HashMap[K, V]
Definition Classes
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override def iterator: Iterator[(K, V)]
Definition Classes
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override def keysIterator: Iterator[K]
Definition Classes
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override def valuesIterator: Iterator[V]
Definition Classes
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override def stepper[S <: Stepper[]](shape: StepperShape[(K, V), S]): S & EfficientSplit
Definition Classes
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override def keyStepper[S <: Stepper[]](shape: StepperShape[K, S]): S & EfficientSplit
Definition Classes
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override def valueStepper[S <: Stepper[]](shape: StepperShape[V, S]): S & EfficientSplit
Definition Classes
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override def clear(): Unit
Definition Classes
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def get(key: K): Option[V]
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@throws(scala.throws.$lessinit$greater$default$1[scala.NoSuchElementException])
override def apply(key: K): V
Definition Classes
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override def getOrElse[V1 >: V](key: K, default: => V1): V1
Definition Classes
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override def getOrElseUpdate(key: K, defaultValue: => V): V
Definition Classes
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override def put(key: K, value: V): Option[V]
Definition Classes
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override def remove(key: K): Option[V]
Definition Classes
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override def update(key: K, value: V): Unit
Definition Classes
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def addOne(elem: (K, V)): HashMap[K, V]
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def subtractOne(elem: K): HashMap[K, V]
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override def knownSize: Int
Definition Classes
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override def isEmpty: Boolean
Definition Classes
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override def foreach[U](f: (K, V) => U): Unit
Definition Classes
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override def filterInPlace(p: (K, V) => Boolean): HashMap[K, V]
Definition Classes
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override def mapFactory: MapFactory[[K, V] =>> HashMap[K, V]]
Definition Classes
Map -> Map -> MapOps
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override def hashCode: Int
Definition Classes
Map -> Any
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Inherited methods

def reduceRightOption[B >: (K, V)](op: ((K, V), B) => B): Option[B]
Optionally applies a binary operator to all elements of this collection, going right to left.
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.
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
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def last: (K, V)
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.
Throws
NoSuchElementException
NoSuchElementException
Inhertied from
IterableOps
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def values: Iterable[V]
Collects all values of this map in an iterable collection.
Returns
the values of this map as an iterable.
Inhertied from
MapOps
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def runWith[U](action: V => U): K => Boolean
Composes this partial function with an action function which gets applied to results of this partial function. 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.
Value Params
action
the action function
Returns
a function which maps arguments x to isDefinedAt(x). The resulting function runs action(this(x)) where this is defined.
See also
applyOrElse.
Inhertied from
PartialFunction
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@throws(scala.throws.$lessinit$greater$default$1[scala.NoSuchElementException])
def default(key: K): V
Defines the default value computation for the map, returned when a key is not found The method implemented here throws an exception, but it might be overridden in subclasses.
Value Params
key
the given key value for which a binding is missing.
Throws
NoSuchElementException
NoSuchElementException
Inhertied from
MapOps
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override def collect[B](pf: PartialFunction[(K, V), B]): Iterable[B]
override def collect[K2, V2](pf: PartialFunction[(K, V), (K2, V2)]): HashMap[K2, V2]
Definition Classes
Inhertied from
StrictOptimizedMapOps
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@deprecated("Use foldLeft instead of /:", "2.13.0") @inline
final def /:[B](z: B)(op: (B, (K, V)) => B): B
Inhertied from
IterableOnceOps
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def collectFirst[B](pf: PartialFunction[(K, V), B]): Option[B]
Finds the first element of the collection for which the given partial function is defined, and applies the partial function to it.
Note: may not terminate for infinite-sized 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
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def groupMap[K, B](key: (K, V) => K)(f: (K, V) => B): Map[K, Iterable[B]]
Partitions this iterable collection into a map of iterable collections according to a discriminator function key. 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
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override def zip[B](that: IterableOnce[B]): Iterable[((K, V), B)]
def drop(n: Int): HashMap[K, V]
Inhertied from
IterableOps
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def withDefault(d: K => V): Map[K, V]
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 withDefaultValue.
Invoking transformer methods (e.g. map) will not preserve the default value.
Value Params
d
the function mapping keys to values, used for non-present keys
Returns
a wrapper of the map with a default value
Inhertied from
Map
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def toVector: Vector[(K, V)]
Inhertied from
IterableOnceOps
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override def partitionMap[A1, A2](f: (K, V) => Either[A1, A2]): (Iterable[A1], Iterable[A2])
@deprecated("Use .to(LazyList) instead of .toStream", "2.13.0") @inline
final def toStream: Stream[(K, V)]
Inhertied from
IterableOnceOps
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@deprecated("Use -- or removeAll on an immutable Map", "2.13.0")
final def -(key1: K, key2: K, keys: K*): HashMap[K, V]
Inhertied from
MapOps
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@deprecated("Use - or remove on an immutable Map", "2.13.0")
final def -(key: K): HashMap[K, V]
Inhertied from
MapOps
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@deprecated("Consider requiring an immutable Map.", "2.13.0") @inline
def --(keys: IterableOnce[K]): HashMap[K, V]
Inhertied from
MapOps
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def sum[B >: (K, V)](num: Numeric[B]): B
Sums up the elements of this collection.
Note: will not terminate for infinite-sized 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 in num.
Inhertied from
IterableOnceOps
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override def span(p: (K, V) => Boolean): (HashMap[K, V], HashMap[K, V])
override def flatMap[B](f: (K, V) => IterableOnce[B]): Iterable[B]
override def flatMap[K2, V2](f: (K, V) => IterableOnce[(K2, V2)]): HashMap[K2, V2]
Definition Classes
Inhertied from
StrictOptimizedMapOps
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@deprecated("Use mapValuesInPlace instead", "2.13.0") @inline
final def transform(f: (K, V) => V): HashMap[K, V]
Inhertied from
MapOps
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override def filterNot(pred: (K, V) => Boolean): HashMap[K, V]
@deprecated("Use `--=` aka `subtractAll` instead of varargs `-=`; infix operations with an operand of multiple args will be deprecated", "2.13.3")
def -=(elem1: K, elem2: K, elems: K*): HashMap[K, V]
Removes two or more elements from this shrinkable collection.
Value Params
elem1
the first element to remove.
elem2
the second element to remove.
elems
the remaining elements to remove.
Returns
the shrinkable collection itself
Inhertied from
Shrinkable
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final def -=(elem: K): HashMap[K, V]
Alias for subtractOne
Inhertied from
Shrinkable
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def corresponds[B](that: IterableOnce[B])(p: ((K, V), B) => Boolean): Boolean
Tests whether every element of this collection's iterator relates to the corresponding element of another collection by satisfying a test predicate.
Note: will not terminate for infinite-sized 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 and p(x, y) is true for all corresponding elements x of this iterator and y of that, otherwise false
Inhertied from
IterableOnceOps
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def scanRight[B](z: B)(op: ((K, V), B) => B): Iterable[B]
Produces a collection containing cumulative results of applying the operator going right to left. The head of the collection is the last cumulative result.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered.
Note: Even when applied to a view or a lazy collection it will always force the elements.
Example:
List(1, 2, 3, 4).scanRight(0)(_ + _) == List(10, 9, 7, 4, 0)
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
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def fold[A1 >: (K, V)](z: A1)(op: (A1, A1) => A1): A1
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.
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 and z, or z if this collection is empty.
Inhertied from
IterableOnceOps
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@deprecated("Iterable.seq always returns the iterable itself", "2.13.0")
def seq: HashMap[K, V]
Inhertied from
Iterable
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def mapValuesInPlace(f: (K, V) => V): HashMap[K, V]
Applies a transformation function to all values contained in this map. The transformation function produces new values from existing keys associated values.
Value Params
f
the transformation to apply
Returns
the map itself.
Inhertied from
MapOps
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def minByOption[B](f: (K, V) => B)(cmp: Ordering[B]): Option[(K, V)]
Finds the first element which yields the smallest value measured by function f.
Note: will not terminate for infinite-sized 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
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def keySet: Set[K]
Collects all keys of this map in a set.
Returns
a set containing all keys of this map.
Inhertied from
MapOps
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@deprecated("Use `++=` aka `addAll` instead of varargs `+=`; infix operations with an operand of multiple args will be deprecated", "2.13.0") @inline
final def +=(elem1: (K, V), elem2: (K, V), elems: (K, V)*): HashMap[K, V]
Adds two or more elements to this growable collection.
Value Params
elem1
the first element to add.
elem2
the second element to add.
elems
the remaining elements to add.
Returns
the growable collection itself
Inhertied from
Growable
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final def +=(elem: (K, V)): HashMap[K, V]
Alias for addOne
Inhertied from
Growable
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def toArray[B >: (K, V)](evidence$1: ClassTag[B]): Array[B]
Convert collection to array.
Implementation note: DO NOT call Array.from from this method.
Inhertied from
IterableOnceOps
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override def filter(pred: (K, V) => Boolean): HashMap[K, V]
def inits: Iterator[HashMap[K, V]]
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
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def unapply(a: K): Option[V]
Tries to extract a B from an A in a pattern matching expression.
Inhertied from
PartialFunction
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def sliding(size: Int, step: Int): Iterator[HashMap[K, V]]
Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.)
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 than size 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
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def sliding(size: Int): Iterator[HashMap[K, V]]
Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.)
An empty collection returns an empty iterator, and a non-empty collection containing fewer elements than the window size returns an iterator that will produce the original collection as its only element.
Value Params
size
the number of elements per group
Returns
An iterator producing iterable collections of size size, except for a non-empty collection with less than size 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
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def tail: HashMap[K, V]
The rest of the collection without its first element.
Inhertied from
IterableOps
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@deprecated("`aggregate` is not relevant for sequential collections. Use `foldLeft(z)(seqop)` instead.", "2.13.0")
def aggregate[B](z: => B)(seqop: (B, (K, V)) => B, combop: (B, B) => B): B
Inhertied from
IterableOnceOps
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def transpose[B](asIterable: (K, V) => Iterable[B]): Iterable[Iterable[B]]
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 two-dimensional iterable collection of iterable collections which has as nth row the nth column of this iterable collection.
Throws
IllegalArgumentException
IllegalArgumentException
Inhertied from
IterableOps
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def foldLeft[B](z: B)(op: (B, (K, V)) => B): B
Applies a binary operator to a start value and all elements of this collection, going left to right.
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.
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 value z on the left: op(...op(z, x1), x2, ..., xn) where x1, ..., xn are the elements of this collection. Returns z if this collection is empty.
Inhertied from
IterableOnceOps
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override def clone(): HashMap[K, V]
Definition Classes
Inhertied from
MapOps
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override def withFilter(p: (K, V) => Boolean): WithFilter[K, V, [A] =>> Iterable[A], [K, V] =>> HashMap[K, V]]
Definition Classes
Inhertied from
MapFactoryDefaults
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final def addString(b: StringBuilder): StringBuilder
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
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final def addString(b: StringBuilder, sep: String): StringBuilder
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
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override def addString(sb: StringBuilder, start: String, sep: String, end: String): StringBuilder
Definition Classes
Inhertied from
MapOps
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def toList: List[(K, V)]
Inhertied from
IterableOnceOps
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def lift: K => Option[V]
Turns this partial function into a plain function returning an Option result.
Returns
a function that takes an argument x to Some(this(x)) if this is defined for x, and to None otherwise.
See also
Function.unlift
Inhertied from
PartialFunction
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@deprecated("Use toIterable instead", "2.13.0")
final def toTraversable: Iterable[(K, V)]
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
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def foldRight[B](z: B)(op: ((K, V), B) => B): B
Applies a binary operator to all elements of this collection and a start value, going right to left.
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.
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 value z on the right: op(x1, op(x2, ... op(xn, z)...)) where x1, ..., xn are the elements of this collection. Returns z if this collection is empty.
Inhertied from
IterableOnceOps
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override def map[B](f: (K, V) => B): Iterable[B]
override def map[K2, V2](f: (K, V) => (K2, V2)): HashMap[K2, V2]
Definition Classes
Inhertied from
StrictOptimizedMapOps
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def toSeq: Seq[(K, V)]
Returns
This collection as a Seq[A]. This is equivalent to to(Seq) but might be faster.
Inhertied from
IterableOnceOps
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def minBy[B](f: (K, V) => B)(cmp: Ordering[B]): (K, V)
Finds the first element which yields the smallest value measured by function f.
Note: will not terminate for infinite-sized 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
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override def empty: HashMap[K, V]
Definition Classes
Inhertied from
MapFactoryDefaults
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@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")
def mapValues[W](f: V => W): MapView[K, W]
Transforms this map by applying a function to every retrieved value.
Value Params
f
the function used to transform values of this map.
Returns
a map view which maps every key of this map to f(this(key)). The resulting map wraps the original map without copying any elements.
Inhertied from
MapOps
Source
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def foreachEntry[U](f: (K, V) => U): Unit
Apply f to each key/value pair for its side effects Note: [U] parameter needed to help scalac's type inference.
Inhertied from
MapOps
Source
(source)
override def partition(p: (K, V) => Boolean): (HashMap[K, V], HashMap[K, V])
final def ++=(xs: IterableOnce[(K, V)]): HashMap[K, V]
Alias for addAll
Inhertied from
Growable
Source
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@deprecatedOverriding("nonEmpty is defined as !isEmpty; override isEmpty instead", "2.13.0")
def nonEmpty: Boolean
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("Check .knownSize instead of .hasDefiniteSize for more actionable information (see scaladoc for details)", "2.13.0")
def hasDefiniteSize: Boolean
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.
See also
method knownSize for a more useful alternative
Inhertied from
IterableOnceOps
Source
(source)
def compose[R](k: PartialFunction[R, K]): PartialFunction[R, V]
Composes another partial function k with this partial function so that this partial function gets applied to results 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 to this(k(x)).
Inhertied from
PartialFunction
Source
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def compose[A](g: A => K): A => V
Composes two instances of Function1 in a new Function1, with this function applied last.
Type Params
A
the type to which function g can be applied
Value Params
g
a function A => T1
Returns
a new function f such that f(x) == apply(g(x))
Inhertied from
Function1
Source
(source)
@deprecated("Use ++ with an explicit collection argument instead of + with varargs", "2.13.0")
override def +[V1 >: V](elem1: (K, V1), elem2: (K, V1), elems: (K, V1)*): HashMap[K, V1]
Definition Classes
Inhertied from
StrictOptimizedMapOps
Source
(source)
@deprecated("Consider requiring an immutable Map or fall back to Map.concat.", "2.13.0")
def +[V1 >: V](kv: (K, V1)): HashMap[K, V1]
Inhertied from
MapOps
Source
(source)
def sizeCompare(that: Iterable[]): Int
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 where
x <  0       if this.size <  that.size
x == 0       if this.size == that.size
x >  0       if this.size >  that.size
The method as implemented here does not call size directly; its running time is O(this.size min that.size) instead of O(this.size + that.size). The method should be overridden if computing size is cheap and knownSize returns -1.
Inhertied from
IterableOps
Source
(source)
def sizeCompare(otherSize: Int): Int
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 where
x <  0       if this.size <  otherSize
x == 0       if this.size == otherSize
x >  0       if this.size >  otherSize
The method as implemented here does not call size directly; its running time is O(size min otherSize) instead of O(size). The method should be overridden if computing size is cheap and knownSize returns -1.
See also
Inhertied from
IterableOps
Source
(source)
def mapResult[NewTo](f: HashMap[K, V] => NewTo): Builder[(K, V), NewTo]
A builder resulting from this builder my mapping the result using f.
Inhertied from
Builder
Source
(source)
override def toString(): String
Definition Classes
Map -> Function1 -> Iterable -> Any
Inhertied from
Map
Source
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override def tapEach[U](f: (K, V) => U): HashMap[K, V]
def lazyZip[B](that: Iterable[B]): LazyZip2[(K, V), B, HashMap[K, V]]
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 to lazyZip. Implicit conversion to Iterable[(A, B)] is also supported.
Inhertied from
Iterable
Source
(source)
protected def reversed: Iterable[(K, V)]
Inhertied from
IterableOnceOps
Source
(source)
def reduceRight[B >: (K, V)](op: ((K, V), B) => B): B
Applies a binary operator to all elements of this collection, going right to left.
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.
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(xn-1, xn)...)) where x1, ..., xn are the elements of this collection.
Throws
UnsupportedOperationException
UnsupportedOperationException
Inhertied from
IterableOnceOps
Source
(source)
def withDefaultValue(d: V): Map[K, V]
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.
Invoking transformer methods (e.g. map) will not preserve the default value.
Value Params
d
default value used for non-present keys
Returns
a wrapper of the map with a default value
Inhertied from
Map
Source
(source)
def min[B >: (K, V)](ord: Ordering[B]): (K, V)
Finds the smallest element.
Note: will not terminate for infinite-sized 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
final def copyToBuffer[B >: (K, V)](dest: Buffer[B]): Unit
Inhertied from
IterableOnceOps
Source
(source)
def isDefinedAt(key: K): Boolean
Tests whether this map contains a binding for a key. This method, which implements an abstract method of trait PartialFunction, is equivalent to contains.
Value Params
key
the key
Returns
true if there is a binding for key in this map, false otherwise.
Inhertied from
MapOps
Source
(source)
def toMap[K, V](ev: (K, V) <:< (K, V)): Map[K, V]
Inhertied from
IterableOnceOps
Source
(source)
def maxByOption[B](f: (K, V) => B)(cmp: Ordering[B]): Option[(K, V)]
Finds the first element which yields the largest value measured by function f.
Note: will not terminate for infinite-sized 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)
override def splitAt(n: Int): (HashMap[K, V], HashMap[K, V])
Definition Classes
Inhertied from
IterableOps
Source
(source)
def groupBy[K](f: (K, V) => K): Map[K, HashMap[K, V]]
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 key k is bound to a iterable collection of those elements x for which f(x) equals k.
Inhertied from
IterableOps
Source
(source)
def result(): HashMap[K, V]
Inhertied from
MapOps
Source
(source)
@deprecated("Use .iterator instead of .toIterator", "2.13.0") @inline
final def toIterator: Iterator[(K, V)]
Inhertied from
IterableOnceOps
Source
(source)
final def sizeHint(coll: IterableOnce[], delta: Int): Unit
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 has a known size 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.
Value Params
coll
the collection which serves as a hint for the result's size.
delta
a correction to add to the coll.size to produce the size hint.
Inhertied from
Builder
Source
(source)
def find(p: (K, V) => Boolean): Option[(K, V)]
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.
Value Params
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.
Inhertied from
IterableOnceOps
Source
(source)
def dropWhile(p: (K, V) => Boolean): HashMap[K, V]
Inhertied from
IterableOps
Source
(source)
final def toIterable: HashMap[K, V]
Inhertied from
Iterable
Source
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@deprecated("Use iterableFactory instead", "2.13.0") @deprecatedOverriding("Use iterableFactory instead", "2.13.0") @inline
def companion: IterableFactory[[A] =>> Iterable[A]]
Inhertied from
IterableOps
Source
(source)
def maxBy[B](f: (K, V) => B)(cmp: Ordering[B]): (K, V)
Finds the first element which yields the largest value measured by function f.
Note: will not terminate for infinite-sized 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)
def andThen[C](k: PartialFunction[V, C]): PartialFunction[K, C]
Composes this partial function with another partial function that gets applied to results of this partial function.
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 to k(this(x)).
Inhertied from
PartialFunction
Source
(source)
override def andThen[C](k: V => C): PartialFunction[K, C]
Composes this partial function with a transformation function that gets applied to results of this partial function.
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 to k(this(x)).
Definition Classes
Inhertied from
PartialFunction
Source
(source)
override def takeRight(n: Int): HashMap[K, V]
A collection containing the last n elements of this collection.
Note: Even when applied to a view or a lazy collection it will always force the elements.
Definition Classes
Inhertied from
StrictOptimizedIterableOps
Source
(source)
override def scanLeft[B](z: B)(op: (B, (K, V)) => B): Iterable[B]
def slice(from: Int, until: Int): HashMap[K, V]
Inhertied from
IterableOps
Source
(source)
override def unzip[A1, A2](asPair: (K, V) => (A1, A2)): (Iterable[A1], Iterable[A2])
def grouped(size: Int): Iterator[HashMap[K, V]]
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 size size if the elements don't divide evenly.
See also
scala.collection.Iterator, method grouped
Inhertied from
IterableOps
Source
(source)
def toIndexedSeq: IndexedSeq[(K, V)]
Inhertied from
IterableOnceOps
Source
(source)
def maxOption[B >: (K, V)](ord: Ordering[B]): Option[(K, V)]
Finds the largest element.
Note: will not terminate for infinite-sized 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)
def product[B >: (K, V)](num: Numeric[B]): B
Multiplies up the elements of this collection.
Note: will not terminate for infinite-sized 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 in num.
Inhertied from
IterableOnceOps
Source
(source)
override def iterableFactory: IterableFactory[[A] =>> Iterable[A]]
Definition Classes
Inhertied from
Iterable
Source
(source)
def keys: Iterable[K]
Collects all keys of this map in an iterable collection.
Returns
the keys of this map as an iterable.
Inhertied from
MapOps
Source
(source)
def orElse[A1 <: K, B1 >: V](that: PartialFunction[A1, B1]): PartialFunction[A1, B1]
Composes this partial function with a fallback partial function which gets applied where this partial function is not defined.
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 takes x to this(x) where this is defined, and to that(x) where it is not.
Inhertied from
PartialFunction
Source
(source)
def to[C1](factory: Factory[(K, V), C1]): C1
Given a collection factory factory, convert this collection to the appropriate representation for the current element type A. Example uses:
xs.to(List) xs.to(ArrayBuffer) xs.to(BitSet) // for xs: Iterable[Int]
Inhertied from
IterableOnceOps
Source
(source)
def scan[B >: (K, V)](z: B)(op: (B, B) => B): Iterable[B]
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)
def headOption: Option[(K, V)]
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)
def forall(p: (K, V) => Boolean): Boolean
Tests whether a predicate holds for all elements of this collection.
Note: may not terminate for infinite-sized collections.
Value Params
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.
Inhertied from
IterableOnceOps
Source
(source)
@deprecated("Use foldRight instead of :\\", "2.13.0") @inline
final def :\[B](z: B)(op: ((K, V), B) => B): B
Inhertied from
IterableOnceOps
Source
(source)
final def ++[B >: (K, V)](suffix: IterableOnce[B]): Iterable[B]
Alias for concat
Inhertied from
IterableOps
Source
(source)
def ++[V2 >: V](xs: IterableOnce[(K, V2)]): HashMap[K, V2]
Alias for concat
Inhertied from
MapOps
Source
(source)
def copyToArray[B >: (K, V)](xs: Array[B], start: Int, len: Int): Int
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 3-arg version of this method", since = "2.13.4")
def copyToArray[B >: (K, V)](xs: Array[B], start: Int): Int
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 3-arg version of this method", since = "2.13.4")
def copyToArray[B >: (K, V)](xs: Array[B]): Int
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)
def minOption[B >: (K, V)](ord: Ordering[B]): Option[(K, V)]
Finds the smallest element.
Note: will not terminate for infinite-sized 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)
final def mkString: 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.
Inhertied from
IterableOnceOps
Source
(source)
final def mkString(sep: String): String
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 string sep.
Example
List(1, 2, 3).mkString("|") = "1|2|3"
Inhertied from
IterableOnceOps
Source
(source)
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.
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 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
List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"
Inhertied from
IterableOnceOps
Source
(source)
@deprecated("Use m.clone().addOne((k,v)) instead of m.updated(k, v)", "2.13.0")
def updated[V1 >: V](key: K, value: V1): HashMap[K, V1]
Inhertied from
MapOps
Source
(source)
def reduceOption[B >: (K, V)](op: (B, B) => B): Option[B]
Reduces the elements of this collection, if any, using the specified associative binary operator.
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, and None otherwise.
Inhertied from
IterableOnceOps
Source
(source)
override protected def fromSpecific(coll: IterableOnce[(K, V)]): HashMap[K, V]
Definition Classes
Inhertied from
MapFactoryDefaults
Source
(source)
def groupMapReduce[K, B](key: (K, V) => K)(f: (K, V) => B)(reduce: (B, B) => B): Map[K, B]
Partitions this iterable collection into a map according to a discriminator function key. 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)
def count(p: (K, V) => Boolean): Int
Counts the number of elements in the collection which satisfy a predicate.
Note: will not terminate for infinite-sized collections.
Value Params
p
the predicate used to test elements.
Returns
the number of elements satisfying the predicate p.
Inhertied from
IterableOnceOps
Source
(source)
def canEqual(that: Any): Boolean
Inhertied from
Map
Source
(source)
def concat[B >: (K, V)](suffix: IterableOnce[B]): Iterable[B]
Returns a new iterable collection containing the elements from the left hand operand followed by the elements from the right hand operand. 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)
override def concat[V2 >: V](suffix: IterableOnce[(K, V2)]): HashMap[K, V2]
Definition Classes
Inhertied from
StrictOptimizedMapOps
Source
(source)
override def isTraversableAgain: Boolean
Definition Classes
Inhertied from
IterableOps
Source
(source)
final def --=(xs: IterableOnce[K]): HashMap[K, V]
Alias for subtractAll
Inhertied from
Shrinkable
Source
(source)
@deprecated("Use filterInPlace instead", "2.13.0") @inline
final def retain(p: (K, V) => Boolean): HashMap[K, V]
Inhertied from
MapOps
Source
(source)
def init: HashMap[K, V]
The initial part of the collection without its last element.
Note: Even when applied to a view or a lazy collection it will always force the elements.
Inhertied from
IterableOps
Source
(source)
final def sizeIs: SizeCompareOps
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")
def filterKeys(p: K => Boolean): MapView[K, V]
Filters this map by retaining only keys satisfying a predicate.
Value Params
p
the predicate used to test keys
Returns
an immutable map consisting only of those key value pairs of this map where the key satisfies the predicate p. The resulting map wraps the original map without copying any elements.
Inhertied from
MapOps
Source
(source)
@deprecated("Use coll instead of repr in a collection implementation, use the collection value itself from the outside", "2.13.0")
final def repr: HashMap[K, V]
Inhertied from
IterableOps
Source
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def reduceLeft[B >: (K, V)](op: (B, (K, V)) => B): B
Applies a binary operator to all elements of this collection, going left to right.
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.
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) ..., xn-1), xn) where x1, ..., xn are the elements of this collection.
Throws
UnsupportedOperationException
UnsupportedOperationException
Inhertied from
IterableOnceOps
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def toSet[B >: (K, V)]: Set[B]
Inhertied from
IterableOnceOps
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override protected def newSpecificBuilder: Builder[(K, V), HashMap[K, V]]
Definition Classes
Inhertied from
MapFactoryDefaults
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def exists(p: (K, V) => Boolean): Boolean
Tests whether a predicate holds for at least one element of this collection.
Note: may not terminate for infinite-sized collections.
Value Params
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
Inhertied from
IterableOnceOps
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override def applyOrElse[K1 <: K, V1 >: V](x: K1, default: K1 => V1): V1
Definition Classes
Inhertied from
MapOps
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final def toBuffer[B >: (K, V)]: Buffer[B]
Inhertied from
IterableOnceOps
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override def dropRight(n: Int): HashMap[K, V]
The rest of the collection without its n last elements. For linear, immutable collections this should avoid making a copy.
Note: Even when applied to a view or a lazy collection it will always force the elements.
Definition Classes
Inhertied from
StrictOptimizedIterableOps
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def takeWhile(p: (K, V) => Boolean): HashMap[K, V]
Takes longest prefix of elements that satisfy a predicate.
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
the longest prefix of this iterable collection whose elements all satisfy the predicate p.
Inhertied from
IterableOps
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def take(n: Int): HashMap[K, V]
Inhertied from
IterableOps
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override def unzip3[A1, A2, A3](asTriple: (K, V) => (A1, A2, A3)): (Iterable[A1], Iterable[A2], Iterable[A3])
def zipAll[A1 >: (K, V), B](that: Iterable[B], thisElem: A1, thatElem: B): Iterable[(A1, B)]
Returns a iterable collection formed from this iterable collection and another iterable collection by combining corresponding elements in pairs. 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 and that. The length of the returned collection is the maximum of the lengths of this iterable collection and that. If this iterable collection is shorter than that, thisElem values are used to pad the result. If that is shorter than this iterable collection, thatElem values are used to pad the result.
Inhertied from
IterableOps
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def elementWise: ElementWiseExtractor[K, V]
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
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def max[B >: (K, V)](ord: Ordering[B]): (K, V)
Finds the largest element.
Note: will not terminate for infinite-sized 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
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final def sizeHintBounded(size: Int, boundingColl: Iterable[]): Unit
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.
Value Params
boundingColl
the bounding collection. If it is an IndexedSeqLike, then sizes larger than collection's size are reduced.
size
the hint how many elements will be added.
Inhertied from
Builder
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override def flatten[B](toIterableOnce: (K, V) => IterableOnce[B]): Iterable[B]
@deprecated("Use ++ instead of ++: for collections of type Iterable", "2.13.0")
def ++:[B >: (K, V)](that: IterableOnce[B]): Iterable[B]
Inhertied from
IterableOps
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@deprecated("Use ++ instead of ++: for collections of type Iterable", "2.13.0")
def ++:[V1 >: V](that: IterableOnce[(K, V1)]): HashMap[K, V1]
Inhertied from
MapOps
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@deprecated("Use .view.slice(from, until) instead of .view(from, until)", "2.13.0")
def view(from: Int, until: Int): View[(K, V)]
A view over a slice of the elements of this collection.
Inhertied from
IterableOps
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override def view: MapView[K, V]
Definition Classes
Inhertied from
MapOps
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def reduceLeftOption[B >: (K, V)](op: (B, (K, V)) => B): Option[B]
Optionally applies a binary operator to all elements of this collection, going left to right.
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.
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
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def tails: Iterator[HashMap[K, V]]
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
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override def equals(o: Any): Boolean
Definition Classes
Map -> Equals -> Any
Inhertied from
Map
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def reduce[B >: (K, V)](op: (B, B) => B): B
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
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def lastOption: Option[(K, V)]
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
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