Map

Companion object Map

trait Map[K, V] extends Iterable[(K, V)] with collection.Map[K, V] with MapOps[K, V, Map, Map[K, V]]

Base type of mutable Maps

Linear Supertypes

MapOps[K, V, Map, Map[K, V]], Shrinkable[K], collection.Map[K, V], collection.MapOps[K, V, Map, Map[K, V]], Equals, PartialFunction[K, V], (K) ⇒ V, Iterable[(K, V)], IterableOps[(K, V), Iterable, Map[K, V]], Growable[(K, V)], collection.Iterable[(K, V)], collection.IterableOps[(K, V), Iterable, Map[K, V]], IterableOnce[(K, V)], AnyRef, Any

Known Subclasses

Map, TrieMap, HashMap, LinkedHashMap, SortedMap, TreeMap

Ordering

Alphabetic
By Inheritance

Inherited

Map
MapOps
Shrinkable
Map
MapOps
Equals
PartialFunction
Function1
Iterable
IterableOps
Growable
Iterable
IterableOps
IterableOnce
AnyRef
Any

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Visibility

Public
All

Type Members

class WithFilter extends collection.WithFilter[A, CC]
A template trait that contains just the map, flatMap, foreach and withFilter methods of trait Iterable.
A template trait that contains just the map, flatMap, foreach and withFilter methods of trait Iterable.

Definition Classes
IterableOps
trait GenKeySet extends Serializable
A generic trait that is reused by keyset implementations
A generic trait that is reused by keyset implementations

Attributes
protected
Definition Classes
MapOps
class KeySet extends Set[K] with GenKeySet
The implementation class of the set returned by keySet.
The implementation class of the set returned by keySet.

Attributes
protected
Definition Classes
MapOps
class MapWithFilter extends WithFilter
Specializes WithFilter for Map collection types
Specializes WithFilter for Map collection types

Definition Classes
MapOps

Abstract Value Members

abstract def add(elem: (K, V)): Map.this.type
${Add}s a single element to this $coll.
${Add}s a single element to this $coll.
elem
the element to $add.
returns
the $coll itself

Definition Classes
Growable
abstract def clear(): Unit
Clears the $coll's contents.
Clears the $coll's contents. After this operation, the $coll is empty.

Definition Classes
Growable
abstract def empty: Map[K, V]
The empty map of the same type as this map
The empty map of the same type as this map
returns
an empty map of type Repr.

Definition Classes
MapOps
abstract def fromSpecificIterable(coll: collection.Iterable[(K, V)]): Map[K, V]

Attributes
protected[this]
Definition Classes
IterableOps
abstract def get(key: K): Option[V]
Optionally returns the value associated with a key.
Optionally returns the value associated with a key.
key
the key value
returns
an option value containing the value associated with key in this map, or None if none exists.

Definition Classes
MapOps
abstract def iterator(): Iterator[(K, V)]
Iterator can be used only once
Iterator can be used only once

Definition Classes
IterableOnce
abstract def mapFactory: MapFactory[Map]

Definition Classes
MapOps
abstract def mapFromIterable[K2, V2](it: collection.Iterable[(K2, V2)]): Map[K2, V2]
Similar to fromIterable, but returns a Map collection type
Similar to fromIterable, but returns a Map collection type

Attributes
protected[this]
Definition Classes
MapOps
abstract def newSpecificBuilder(): Builder[(K, V), Map[K, V]]
returns
a strict builder for the same collection type. Note that in the case of lazy collections (e.g. View or immutable.LazyList), it is possible to implement this method but the resulting Builder will break laziness. As a consequence, operations should preferably be implemented on top of views rather than builders.

Attributes
protected[this]
Definition Classes
IterableOps
abstract def subtract(elem: K): Map.this.type
Removes a single element from this shrinkable collection.
Removes a single element from this shrinkable collection.
elem
the element to remove.
returns
the shrinkable collection itself

Definition Classes
Shrinkable

Concrete Value Members

final def !=(arg0: Any): Boolean

Definition Classes
AnyRef → Any
final def ##(): Int

Definition Classes
AnyRef → Any
def ++[V2 >: V](xs: collection.Iterable[(K, V2)]): Map[K, V2]
Alias for concat
Alias for concat

Definition Classes
MapOps
final def ++[B >: (K, V)](suffix: collection.Iterable[B]): Iterable[B]
Alias for concat
Alias for concat

Definition Classes
IterableOps
Annotations
@inline()
final def ++=(xs: IterableOnce[(K, V)]): Map.this.type
Alias for addAllInPlace
Alias for addAllInPlace

Definition Classes
Growable
Annotations
@inline()
final def +=(elem1: (K, V), elem2: (K, V), elems: (K, V)*): Map.this.type
${Add}s two or more elements to this $coll.
${Add}s two or more elements to this $coll.
elem1
the first element to $add.
elem2
the second element to $add.
elems
the remaining elements to $add.
returns
the $coll itself

Definition Classes
Growable
Annotations
@inline()
final def +=(elem: (K, V)): Map.this.type
Alias for add
Alias for add

Definition Classes
Growable
Annotations
@inline()
final def --=(xs: IterableOnce[K]): Map.this.type
Alias for subtractAll
Alias for subtractAll

Definition Classes
Shrinkable
Annotations
@inline()
final def -=(elem1: K, elem2: K, elems: K*): Map.this.type
Alias for subtract
Alias for subtract

Definition Classes
Shrinkable
Annotations
@inline()
final def -=(elem: K): Map.this.type
Alias for subtract
Alias for subtract

Definition Classes
Shrinkable
Annotations
@inline()
final def ==(arg0: Any): Boolean

Definition Classes
AnyRef → Any
def addAll(xs: IterableOnce[(K, V)]): Map.this.type
${Add}s all elements produced by a TraversableOnce to this $coll.
${Add}s all elements produced by a TraversableOnce to this $coll.
xs
the TraversableOnce producing the elements to $add.
returns
the $coll itself.

Definition Classes
Growable
def andThen[C](k: (V) ⇒ C): PartialFunction[K, C]

Definition Classes
PartialFunction → Function1
def apply(key: K): V
Retrieves the value which is associated with the given key.
Retrieves the value which is associated with the given key. This method invokes the default method of the map if there is no mapping from the given key to a value. Unless overridden, the default method throws a NoSuchElementException.
key
the key
returns
the value associated with the given key, or the result of the map's default method, if none exists.

Definition Classes
MapOps → Function1
Annotations
@throws( ... )
def applyOrElse[K1 <: K, V1 >: V](x: K1, default: (K1) ⇒ V1): V1

Definition Classes
MapOps → PartialFunction
final def asInstanceOf[T0]: T0

Definition Classes
Any
def canEqual(that: Any): Boolean

Definition Classes
MapOps → Equals
def className: String
The class name of this collection.
The class name of this collection. To be used for converting to string. Collections generally print like this:
<className>(elem_1, ..., elem_n)

Definition Classes
IterableOps
def clone(): Map[K, V]

Definition Classes
MapOps → AnyRef
final def coll: Map.this.type
returns
This collection as a C.

Attributes
protected[this]
Definition Classes
Map → IterableOps
def collect[B](pf: PartialFunction[(K, V), B]): Iterable[B]

Definition Classes
IterableOps
def collectFirst[B](pf: PartialFunction[(K, V), B]): Option[B]
Finds the first element of the $coll for which the given partial function is defined, and applies the partial function to it.
Finds the first element of the $coll for which the given partial function is defined, and applies the partial function to it.
$mayNotTerminateInf $orderDependent
pf
the partial function
returns
an option value containing pf applied to the first value for which it is defined, or None if none exists.
Definition Classes
IterableOps
Example:
1. Seq("a", 1, 5L).collectFirst({ case x: Int => x*10 }) = Some(10)
def compose[A](g: (A) ⇒ K): (A) ⇒ V

Definition Classes
Function1
Annotations
@unspecialized()
def concat[V2 >: V](xs: collection.Iterable[(K, V2)]): Map[K, V2]

Definition Classes
MapOps
final def concat[B >: (K, V)](suffix: collection.Iterable[B]): Iterable[B]

Definition Classes
IterableOps
Annotations
@inline()
def contains(key: K): Boolean
Tests whether this map contains a binding for a key.
Tests whether this map contains a binding for a key.
key
the key
returns
true if there is a binding for key in this map, false otherwise.

Definition Classes
MapOps
def copyToArray[B >: (K, V)](xs: Array[B], start: Int = 0): xs.type
Copy all elements of this collection to array xs, starting at start.
Copy all elements of this collection to array xs, starting at start.

Definition Classes
IterableOps
def count(p: ((K, V)) ⇒ Boolean): Int
Counts the number of elements in the $coll which satisfy a predicate.
Counts the number of elements in the $coll which satisfy a predicate.
p
the predicate used to test elements.
returns
the number of elements satisfying the predicate p.

Definition Classes
IterableOps
def default(key: K): V
Defines the default value computation for the map, returned when a key is not found The method implemented here throws an exception, but it might be overridden in subclasses.
Defines the default value computation for the map, returned when a key is not found The method implemented here throws an exception, but it might be overridden in subclasses.
key
the given key value for which a binding is missing.

Definition Classes
MapOps
Annotations
@throws( ... )
Exceptions thrown
def drop(n: Int): Map[K, V]
The rest of the collection without its n first elements.
The rest of the collection without its n first elements. For linear, immutable collections this should avoid making a copy.

Definition Classes
IterableOps
def dropRight(n: Int): Map[K, V]
The rest of the collection without its n last elements.
The rest of the collection without its n last elements. For linear, immutable collections this should avoid making a copy.

Definition Classes
IterableOps
def dropWhile(p: ((K, V)) ⇒ Boolean): Map[K, V]
Skips longest sequence of elements of this iterator which satisfy given predicate p, and returns an iterator of the remaining elements.
Skips longest sequence of elements of this iterator which satisfy given predicate p, and returns an iterator of the remaining elements.
p
the predicate used to skip elements.
returns
an iterator consisting of the remaining elements

Definition Classes
IterableOps
Note
Reuse: $consumesAndProducesIterator
final def eq(arg0: AnyRef): Boolean

Definition Classes
AnyRef
def equals(o: Any): Boolean

Definition Classes
MapOps → Equals → AnyRef → Any
def exists(p: ((K, V)) ⇒ Boolean): Boolean
Tests whether a predicate holds for at least one element of this $coll.
Tests whether a predicate holds for at least one element of this $coll.
$mayNotTerminateInf
p
the predicate used to test elements.
returns
true if the given predicate p is satisfied by at least one element of this $coll, otherwise false

Definition Classes
IterableOps
def filter(pred: ((K, V)) ⇒ Boolean): Map[K, V]
Selects all elements of this $coll which satisfy a predicate.
Selects all elements of this $coll which satisfy a predicate.
pred
the predicate used to test elements.
returns
a new $coll consisting of all elements of this $coll that satisfy the given predicate pred. Their order may not be preserved.

Definition Classes
IterableOps
def filterInPlace(p: ((K, V)) ⇒ Boolean): Map.this.type

Definition Classes
MapOps → IterableOps
def filterKeys(p: (K) ⇒ Boolean): View[(K, V)]
Filters this map by retaining only keys satisfying a predicate.
Filters this map by retaining only keys satisfying a predicate.
p
the predicate used to test keys
returns
an immutable map consisting only of those key value pairs of this map where the key satisfies the predicate p. The resulting map wraps the original map without copying any elements.

Definition Classes
MapOps
def filterNot(pred: ((K, V)) ⇒ Boolean): Map[K, V]
Selects all elements of this $coll which do not satisfy a predicate.
Selects all elements of this $coll which do not satisfy a predicate.
pred
the predicate used to test elements.
returns
a new $coll consisting of all elements of this $coll that do not satisfy the given predicate pred. Their order may not be preserved.

Definition Classes
IterableOps
def finalize(): Unit

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( classOf[java.lang.Throwable] )
def find(p: ((K, V)) ⇒ Boolean): Option[(K, V)]
Finds the first element of the $coll satisfying a predicate, if any.
Finds the first element of the $coll satisfying a predicate, if any.
$mayNotTerminateInf $orderDependent
p
the predicate used to test elements.
returns
an option value containing the first element in the $coll that satisfies p, or None if none exists.

Definition Classes
IterableOps
def flatMap[K2, V2](f: ((K, V)) ⇒ IterableOnce[(K2, V2)]): Map[K2, V2]

Definition Classes
MapOps
def flatMap[B](f: ((K, V)) ⇒ IterableOnce[B]): Iterable[B]
Flatmap
Flatmap

Definition Classes
IterableOps
def flatMapInPlace(f: ((K, V)) ⇒ IterableOnce[(K, V)]): Map.this.type

Definition Classes
MapOps → IterableOps
def flatten[B](implicit ev: ((K, V)) ⇒ IterableOnce[B]): Iterable[B]

Definition Classes
IterableOps
def foldLeft[B](z: B)(op: (B, (K, V)) ⇒ B): B
Fold left
Fold left

Definition Classes
IterableOps
def foldRight[B](z: B)(op: ((K, V), B) ⇒ B): B
Fold right
Fold right

Definition Classes
IterableOps
def forall(p: ((K, V)) ⇒ Boolean): Boolean
Tests whether a predicate holds for all elements of this $coll.
Tests whether a predicate holds for all elements of this $coll.
$mayNotTerminateInf
p
the predicate used to test elements.
returns
true if this $coll is empty or the given predicate p holds for all elements of this $coll, otherwise false.

Definition Classes
IterableOps
def foreach[U](f: ((K, V)) ⇒ U): Unit
Apply f to each element for its side effects Note: [U] parameter needed to help scalac's type inference.
Apply f to each element for its side effects Note: [U] parameter needed to help scalac's type inference.

Definition Classes
IterableOps
def fromIterable[E](it: collection.Iterable[E]): Iterable[E]

Attributes
protected[this]
Definition Classes
IterableOps
final def getClass(): Class[_]

Definition Classes
AnyRef → Any
def getOrElse(key: K, default: ⇒ V): V
[use case] Returns the value associated with a key, or a default value if the key is not contained in the map.
[use case]
Returns the value associated with a key, or a default value if the key is not contained in the map.
key
the key.
default
a computation that yields a default value in case no binding for key is found in the map.
returns
the value associated with key if it exists, otherwise the result of the default computation.

Definition Classes
MapOps
Full Signature
def getOrElse[V1 >: V](key: K, default: ⇒ V1): V1
def getOrElseUpdate(key: K, op: ⇒ V): V
If given key is already in this map, returns associated value.
If given key is already in this map, returns associated value.
Otherwise, computes value from given expression op, stores with key in map and returns that value.
Concurrent map implementations may evaluate the expression op multiple times, or may evaluate op without inserting the result.
key
the key to test
op
the computation yielding the value to associate with key, if key is previously unbound.
returns
the value associated with key (either previously or as a result of executing the method).

Definition Classes
MapOps
def groupBy[K](f: ((K, V)) ⇒ K): immutable.Map[K, Map[K, V]]
Partitions this $coll into a map of ${coll}s according to some discriminator function.
Partitions this $coll into a map of ${coll}s according to some discriminator function.
Note: When applied to a view or a lazy collection it will always force the elements.
K
the type of keys returned by the discriminator function.
f
the discriminator function.
returns
A map from keys to ${coll}s 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 $coll of those elements x for which f(x) equals k.
Definition Classes
IterableOps
def groupMap[K, B](key: ((K, V)) ⇒ K)(f: ((K, V)) ⇒ B): immutable.Map[K, Iterable[B]]
Partitions this $coll into a map of ${coll}s according to a discriminator function key.
Partitions this $coll into a map of ${coll}s 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)
```
K
the type of keys returned by the discriminator function
B
the type of values returned by the transformation function
key
the discriminator function
f
the element transformation function

Definition Classes
IterableOps
def groupMapReduce[K, B](key: ((K, V)) ⇒ K)(f: ((K, V)) ⇒ B)(reduce: (B, B) ⇒ B): immutable.Map[K, B]
Partitions this $coll into a map according to a discriminator function key.
Partitions this $coll into a map according to a discriminator function key. All the values that have the same discriminator are then transformed by the value 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)(_ + _)
```
Definition Classes
IterableOps
def grouped(size: Int): Iterator[Map[K, V]]
Partitions elements in fixed size ${coll}s.
Partitions elements in fixed size ${coll}s.
size
the number of elements per group
returns
An iterator producing ${coll}s of size size, except the last will be less than size size if the elements don't divide evenly.

Definition Classes
IterableOps
See also
scala.collection.Iterator, method grouped
def hashCode(): Int

Definition Classes
MapOps → AnyRef → Any
def head: (K, V)
The first element of the collection.
The first element of the collection.

Definition Classes
IterableOps
def init: Map[K, V]
The initial part of the collection without its last element.
The initial part of the collection without its last element.

Definition Classes
IterableOps
def isDefinedAt(key: K): Boolean
Tests whether this map contains a binding for a key.
Tests whether this map contains a binding for a key. This method, which implements an abstract method of trait PartialFunction, is equivalent to contains.
key
the key
returns
true if there is a binding for key in this map, false otherwise.

Definition Classes
MapOps → PartialFunction
def isEmpty: Boolean
Is the collection empty?
Is the collection empty?

Definition Classes
IterableOps
final def isInstanceOf[T0]: Boolean

Definition Classes
Any
def iterableFactory: Iterable.type

Definition Classes
MapOps → IterableOps
def keySet: collection.Set[K]
Collects all keys of this map in a set.
Collects all keys of this map in a set.
returns
a set containing all keys of this map.

Definition Classes
MapOps
def keys: collection.Iterable[K]
Collects all keys of this map in an iterable collection.
Collects all keys of this map in an iterable collection.
returns
the keys of this map as an iterable.

Definition Classes
MapOps
def keysIterator(): Iterator[K]
Creates an iterator for all keys.
Creates an iterator for all keys.
returns
an iterator over all keys.

Definition Classes
MapOps
def knownSize: Int
The number of elements in this collection, if it can be cheaply computed, -1 otherwise.
The number of elements in this collection, if it can be cheaply computed, -1 otherwise. Cheaply usually means: Not requiring a collection traversal.

Definition Classes
IterableOps
def last: (K, V)
Selects the last element.
Selects the last element. $orderDependent
returns
The last element of this $coll.

Definition Classes
IterableOps
Exceptions thrown
NoSuchElementException If the $coll is empty.
def lastOption: Option[(K, V)]
Optionally selects the last element.
Optionally selects the last element. $orderDependent
returns
the last element of this $coll$ if it is nonempty, None if it is empty.

Definition Classes
IterableOps
def lift: (K) ⇒ Option[V]

Definition Classes
PartialFunction
def map[K2, V2](f: ((K, V)) ⇒ (K2, V2)): Map[K2, V2]

Definition Classes
MapOps
def map[B](f: ((K, V)) ⇒ B): Iterable[B]
Builds a new collection by applying a function to all elements of this $coll.
Builds a new collection by applying a function to all elements of this $coll.
B
the element type of the returned collection.
f
the function to apply to each element.
returns
a new $coll resulting from applying the given function f to each element of this $coll and collecting the results.

Definition Classes
IterableOps
def mapInPlace(f: ((K, V)) ⇒ (K, V)): Map.this.type

Definition Classes
MapOps → IterableOps
def mapValues[W](f: (V) ⇒ W): View[(K, W)]
Transforms this map by applying a function to every retrieved value.
Transforms this map by applying a function to every retrieved value.
f
the function used to transform values of this map.
returns
a map view which maps every key of this map to f(this(key)). The resulting map wraps the original map without copying any elements.

Definition Classes
MapOps
def max: (K, V)
[use case] Finds the largest element.
[use case]
Finds the largest element.
returns
the largest element of this shrinkable collection.

Definition Classes
IterableOps
Full Signature
def max[B >: (K, V)](implicit ord: Ordering[B]): (K, V)
def maxBy[B](f: ((K, V)) ⇒ B): (K, V)
[use case] Finds the first element which yields the largest value measured by function f.
[use case]
Finds the first element which yields the largest value measured by function f.
B
The result type of the function f.
f
The measuring function.
returns
the first element of this shrinkable collection with the largest value measured by function f.

Definition Classes
IterableOps
Full Signature
def maxBy[B](f: ((K, V)) ⇒ B)(implicit cmp: Ordering[B]): (K, V)
def min: (K, V)
[use case] Finds the smallest element.
[use case]
Finds the smallest element.
returns
the smallest element of this shrinkable collection

Definition Classes
IterableOps
Full Signature
def min[B >: (K, V)](implicit ord: Ordering[B]): (K, V)
def minBy[B](f: ((K, V)) ⇒ B): (K, V)
[use case] Finds the first element which yields the smallest value measured by function f.
[use case]
Finds the first element which yields the smallest value measured by function f.
B
The result type of the function f.
f
The measuring function.
returns
the first element of this shrinkable collection with the smallest value measured by function f.

Definition Classes
IterableOps
Full Signature
def minBy[B](f: ((K, V)) ⇒ B)(implicit cmp: Ordering[B]): (K, V)
def mkString(start: String, sep: String, end: String): String
A string showing all elements of this collection, separated by string sep.
A string showing all elements of this collection, separated by string sep.

Definition Classes
MapOps → IterableOps
def mkString: String

Definition Classes
IterableOps
def mkString(sep: String): String

Definition Classes
IterableOps
final def ne(arg0: AnyRef): Boolean

Definition Classes
AnyRef
def nonEmpty: Boolean
Is the collection not empty?
Is the collection not empty?

Definition Classes
IterableOps
final def notify(): Unit

Definition Classes
AnyRef
final def notifyAll(): Unit

Definition Classes
AnyRef
def orElse[A1 <: K, B1 >: V](that: PartialFunction[A1, B1]): PartialFunction[A1, B1]

Definition Classes
PartialFunction
def partition(p: ((K, V)) ⇒ Boolean): (Map[K, V], Map[K, V])
A pair of, first, all elements that satisfy prediacte p and, second, all elements that do not.
A pair of, first, all elements that satisfy prediacte p and, second, all elements that do not. Interesting because it splits a collection in two.
The default implementation provided here needs to traverse the collection twice. Strict collections have an overridden version of partition in Buildable, which requires only a single traversal.

Definition Classes
IterableOps
def product: (K, V)
[use case] Multiplies up the elements of this collection.
[use case]
Multiplies up the elements of this collection.
returns
the product of all elements in this shrinkable collection of numbers of type Int. Instead of Int, any other type T with an implicit Numeric[T] implementation can be used as element type of the shrinkable collection and as result type of product. Examples of such types are: Long, Float, Double, BigInt.

Definition Classes
IterableOps
Full Signature
def product[B >: (K, V)](implicit num: Numeric[B]): B
def put(key: K, value: V): Option[V]
Adds a new key/value pair to this map and optionally returns previously bound value.
Adds a new key/value pair to this map and optionally returns previously bound value. If the map already contains a mapping for the key, it will be overridden by the new value.
key
the key to update
value
the new value
returns
an option value containing the value associated with the key before the put operation was executed, or None if key was not defined in the map before.

Definition Classes
MapOps
def reduce[B >: (K, V)](op: (B, B) ⇒ B): B
Reduces the elements of this $coll using the specified associative binary operator.
Reduces the elements of this $coll using the specified associative binary operator.
$undefinedorder
B
A type parameter for the binary operator, a supertype of A.
op
A binary operator that must be associative.
returns
The result of applying reduce operator op between all the elements if the $coll is nonempty.

Definition Classes
IterableOps
Exceptions thrown
UnsupportedOperationException if this $coll is empty.
def reduceLeft[B >: (K, V)](op: (B, (K, V)) ⇒ B): B
Applies a binary operator to all elements of this $coll, going left to right.
Applies a binary operator to all elements of this $coll, going left to right. $willNotTerminateInf $orderDependentFold
B
the result type of the binary operator.
op
the binary operator.
returns
the result of inserting op between consecutive elements of this $coll, going left to right:
```
op( op( ... op(x_1, x_2) ..., x_{n-1}), x_n)
```
where x₁, ..., x_n are the elements of this $coll.
Definition Classes
IterableOps
Exceptions thrown
UnsupportedOperationException if this $coll is empty.
def reduceLeftOption[B >: (K, V)](op: (B, (K, V)) ⇒ B): Option[B]
Optionally applies a binary operator to all elements of this $coll, going left to right.
Optionally applies a binary operator to all elements of this $coll, going left to right. $willNotTerminateInf $orderDependentFold
B
the result type of the binary operator.
op
the binary operator.
returns
an option value containing the result of reduceLeft(op) if this $coll is nonempty, None otherwise.

Definition Classes
IterableOps
def reduceOption[B >: (K, V)](op: (B, B) ⇒ B): Option[B]
Reduces the elements of this $coll, if any, using the specified associative binary operator.
Reduces the elements of this $coll, if any, using the specified associative binary operator.
$undefinedorder
B
A type parameter for the binary operator, a supertype of A.
op
A binary operator that must be associative.
returns
An option value containing result of applying reduce operator op between all the elements if the collection is nonempty, and None otherwise.

Definition Classes
IterableOps
def reduceRight[B >: (K, V)](op: ((K, V), B) ⇒ B): B
Applies a binary operator to all elements of this $coll, going right to left.
Applies a binary operator to all elements of this $coll, going right to left. $willNotTerminateInf $orderDependentFold
B
the result type of the binary operator.
op
the binary operator.
returns
the result of inserting op between consecutive elements of this $coll, going right to left:
```
op(x_1, op(x_2, ..., op(x_{n-1}, x_n)...))
```
where x₁, ..., x_n are the elements of this $coll.
Definition Classes
IterableOps
Exceptions thrown
UnsupportedOperationException if this $coll is empty.
def reduceRightOption[B >: (K, V)](op: ((K, V), B) ⇒ B): Option[B]
Optionally applies a binary operator to all elements of this $coll, going right to left.
Optionally applies a binary operator to all elements of this $coll, going right to left. $willNotTerminateInf $orderDependentFold
B
the result type of the binary operator.
op
the binary operator.
returns
an option value containing the result of reduceRight(op) if this $coll is nonempty, None otherwise.

Definition Classes
IterableOps
def remove(key: K): Option[V]
Removes a key from this map, returning the value associated previously with that key as an option.
Removes a key from this map, returning the value associated previously with that key as an option.
key
the key to be removed
returns
an option value containing the value associated previously with key, or None if key was not defined in the map before.

Definition Classes
MapOps
def reversed: collection.Iterable[(K, V)]

Attributes
protected[this]
Definition Classes
IterableOps
def runWith[U](action: (V) ⇒ U): (K) ⇒ Boolean

Definition Classes
PartialFunction
def scan[B >: (K, V)](z: B)(op: (B, B) ⇒ B): Iterable[B]
Computes a prefix scan of the elements of the collection.
Computes a prefix scan of the elements of the collection.
Note: The neutral element z may be applied more than once.
B
element type of the resulting collection
z
neutral element for the operator op
op
the associative operator for the scan
returns
a new $coll containing the prefix scan of the elements in this $coll

Definition Classes
IterableOps
def scanLeft[B](z: B)(op: (B, (K, V)) ⇒ B): Iterable[B]
Produces a collection containing cumulative results of applying the operator going left to right.
Produces a collection containing cumulative results of applying the operator going left to right.
$willNotTerminateInf $orderDependent
B
the type of the elements in the resulting collection
z
the initial value
op
the binary operator applied to the intermediate result and the element
returns
collection with intermediate results

Definition Classes
IterableOps
def scanRight[B](z: B)(op: ((K, V), B) ⇒ B): Iterable[B]
Produces a collection containing cumulative results of applying the operator going right to left.
Produces a collection containing cumulative results of applying the operator going right to left. The head of the collection is the last cumulative result. $willNotTerminateInf $orderDependent
Example:
```
List(1, 2, 3, 4).scanRight(0)(_ + _) == List(10, 9, 7, 4, 0)
```
B
the type of the elements in the resulting collection
z
the initial value
op
the binary operator applied to the intermediate result and the element
returns
collection with intermediate results

Definition Classes
IterableOps
def size: Int
The number of elements in this collection.
The number of elements in this collection. Does not terminate for infinite collections.

Definition Classes
IterableOps
def slice(from: Int, until: Int): Map[K, V]
Selects an interval of elements.
Selects an interval of elements. The returned collection is made up of all elements x which satisfy the invariant:
```
from <= indexOf(x) < until
```
$orderDependent
from
the lowest index to include from this $coll.
until
the lowest index to EXCLUDE from this $coll.
returns
a $coll containing the elements greater than or equal to index from extending up to (but not including) index until of this $coll.

Definition Classes
IterableOps
def sliding(size: Int, step: Int): Iterator[Map[K, V]]
Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.)
Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.)
size
the number of elements per group
step
the distance between the first elements of successive groups
returns
An iterator producing ${coll}s of size size, except the last element (which may be the only element) will be truncated if there are fewer than size elements remaining to be grouped.

Definition Classes
IterableOps
See also
scala.collection.Iterator, method sliding
def sliding(size: Int): Iterator[Map[K, V]]
Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.) The "sliding window" step is set to one.
Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.) The "sliding window" step is set to one.
size
the number of elements per group
returns
An iterator producing ${coll}s of size size, except the last element (which may be the only element) will be truncated if there are fewer than size elements remaining to be grouped.

Definition Classes
IterableOps
See also
scala.collection.Iterator, method sliding
def span(p: ((K, V)) ⇒ Boolean): (Map[K, V], Map[K, V])
Splits this $coll into a prefix/suffix pair according to a predicate.
Splits this $coll into a prefix/suffix pair according to a predicate.
Note: c span p is equivalent to (but possibly more efficient than) (c takeWhile p, c dropWhile p), provided the evaluation of the predicate p does not cause any side-effects. $orderDependent
p
the test predicate
returns
a pair consisting of the longest prefix of this $coll whose elements all satisfy p, and the rest of this $coll.

Definition Classes
IterableOps
def splitAt(n: Int): (Map[K, V], Map[K, V])
Splits this $coll into two at a given position.
Splits this $coll into two at a given position. Note: c splitAt n is equivalent to (but possibly more efficient than) (c take n, c drop n). $orderDependent
n
the position at which to split.
returns
a pair of ${coll}s consisting of the first n elements of this $coll, and the other elements.

Definition Classes
IterableOps
def subtract(elem1: K, elem2: K, elems: K*): Map.this.type
Removes two or more elements from this shrinkable collection.
Removes two or more elements from this shrinkable collection.
elem1
the first element to remove.
elem2
the second element to remove.
elems
the remaining elements to remove.
returns
the shrinkable collection itself

Definition Classes
Shrinkable
def subtractAll(xs: IterableOnce[K]): Map.this.type
Removes all elements produced by an iterator from this shrinkable collection.
Removes all elements produced by an iterator from this shrinkable collection.
xs
the iterator producing the elements to remove.
returns
the shrinkable collection itself

Definition Classes
Shrinkable
def sum: (K, V)
[use case] Sums up the elements of this collection.
[use case]
Sums up the elements of this collection.
returns
the sum of all elements in this shrinkable collection of numbers of type Int. Instead of Int, any other type T with an implicit Numeric[T] implementation can be used as element type of the shrinkable collection and as result type of sum. Examples of such types are: Long, Float, Double, BigInt.

Definition Classes
IterableOps
Full Signature
def sum[B >: (K, V)](implicit num: Numeric[B]): B
final def synchronized[T0](arg0: ⇒ T0): T0

Definition Classes
AnyRef
def tail: Map[K, V]
The rest of the collection without its first element.
The rest of the collection without its first element.

Definition Classes
IterableOps
def take(n: Int): Map[K, V]
A collection containing the first n elements of this collection.
A collection containing the first n elements of this collection.

Definition Classes
IterableOps
def takeRight(n: Int): Map[K, V]
A collection containing the last n elements of this collection.
A collection containing the last n elements of this collection.

Definition Classes
IterableOps
def takeWhile(p: ((K, V)) ⇒ Boolean): Map[K, V]
Takes longest prefix of elements that satisfy a predicate.
Takes longest prefix of elements that satisfy a predicate. $orderDependent
p
The predicate used to test elements.
returns
the longest prefix of this $coll whose elements all satisfy the predicate p.

Definition Classes
IterableOps
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.
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]

Definition Classes
IterableOps
def toArray[B >: (K, V)](implicit arg0: ClassTag[B]): Array[B]
Convert collection to array.
Convert collection to array.

Definition Classes
IterableOps
final def toIterable: Map.this.type
The collection itself
The collection itself
returns
This collection as an Iterable[A]. No new collection will be built if this is already an Iterable[A].

Definition Classes
Iterable → IterableOps
def toString(): String

Definition Classes
MapOps → Function1 → IterableOps → AnyRef → Any
def unzip[A1, A2](implicit asPair: <:<[(K, V), (A1, A2)]): (Iterable[A1], Iterable[A2])
Converts this $coll of pairs into two collections of the first and second half of each pair.
Converts this $coll of pairs into two collections of the first and second half of each pair.
```
val xs = $Coll(
           (1, "one"),
           (2, "two"),
           (3, "three")).unzip
// xs == ($Coll(1, 2, 3),
//        $Coll(one, two, three))
```
A1
the type of the first half of the element pairs
A2
the type of the second half of the element pairs
asPair
an implicit conversion which asserts that the element type of this $coll is a pair.
returns
a pair of ${coll}s, containing the first, respectively second half of each element pair of this $coll.

Definition Classes
IterableOps
def update(key: K, value: V): Unit
Adds a new key/value pair to this map.
Adds a new key/value pair to this map. If the map already contains a mapping for the key, it will be overridden by the new value.
key
The key to update
value
The new value

Definition Classes
MapOps
def values: collection.Iterable[V]
Collects all values of this map in an iterable collection.
Collects all values of this map in an iterable collection.
returns
the values of this map as an iterable.

Definition Classes
MapOps
def valuesIterator(): Iterator[V]
Creates an iterator for all values in this map.
Creates an iterator for all values in this map.
returns
an iterator over all values that are associated with some key in this map.

Definition Classes
MapOps
def view: View[(K, V)]
A view representing the elements of this collection.
A view representing the elements of this collection.

Definition Classes
IterableOps
final def wait(): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long, arg1: Int): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
def withFilter(p: ((K, V)) ⇒ Boolean): MapWithFilter
Creates a non-strict filter of this $coll.
Creates a non-strict filter of this $coll.
Note: the difference between c filter p and c withFilter p is that the former creates a new collection, whereas the latter only restricts the domain of subsequent map, flatMap, foreach, and withFilter operations. $orderDependent
p
the predicate used to test elements.
returns
an object of class WithFilter, which supports map, flatMap, foreach, and withFilter operations. All these operations apply to those elements of this $coll which satisfy the predicate p.

Definition Classes
MapOps → IterableOps
def zip[B](xs: collection.Iterable[B]): Iterable[((K, V), B)]
Returns a $coll formed from this $coll and another iterable collection by combining corresponding elements in pairs.
Returns a $coll formed from this $coll and another iterable collection by combining corresponding elements in pairs. If one of the two collections is longer than the other, its remaining elements are ignored.
B
the type of the second half of the returned pairs
xs
The iterable providing the second half of each result pair
returns
a new collection of type That containing pairs consisting of corresponding elements of this $coll and that. The length of the returned collection is the minimum of the lengths of this $coll and that.

Definition Classes
IterableOps
def zipWithIndex: Iterable[((K, V), Int)]
Zips this $coll with its indices.
Zips this $coll with its indices.
returns
A new collection of type That containing pairs consisting of all elements of this $coll paired with their index. Indices start at 0.
Definition Classes
IterableOps
Example:
1. List("a", "b", "c").zipWithIndex == List(("a", 0), ("b", 1), ("c", 2))

Packages

Map

Companion object Map

trait Map[K, V] extends Iterable[(K, V)] with collection.Map[K, V] with MapOps[K, V, Map, Map[K, V]]

Type Members

Abstract Value Members

Concrete Value Members

def getOrElse[V1 >: V](key: K, default: ⇒ V1): V1

def max[B >: (K, V)](implicit ord: Ordering[B]): (K, V)

def maxBy[B](f: ((K, V)) ⇒ B)(implicit cmp: Ordering[B]): (K, V)

def min[B >: (K, V)](implicit ord: Ordering[B]): (K, V)

def minBy[B](f: ((K, V)) ⇒ B)(implicit cmp: Ordering[B]): (K, V)

def product[B >: (K, V)](implicit num: Numeric[B]): B

def sum[B >: (K, V)](implicit num: Numeric[B]): B

Inherited from MapOps[K, V, Map, Map[K, V]]

Inherited from Shrinkable[K]

Inherited from collection.Map[K, V]

Inherited from collection.MapOps[K, V, Map, Map[K, V]]

Inherited from Equals

Inherited from PartialFunction[K, V]

Inherited from (K) ⇒ V

Inherited from Iterable[(K, V)]

Inherited from IterableOps[(K, V), Iterable, Map[K, V]]

Inherited from Growable[(K, V)]

Inherited from collection.Iterable[(K, V)]

Inherited from collection.IterableOps[(K, V), Iterable, Map[K, V]]

Inherited from IterableOnce[(K, V)]

Inherited from AnyRef

Inherited from Any

Ungrouped

Packages

Map 

Companion object Map

trait Map[K, V] extends Iterable[(K, V)] with collection.Map[K, V] with MapOps[K, V, Map, Map[K, V]]

Type Members

Abstract Value Members

Concrete Value Members

def getOrElse[V1 >: V](key: K, default: ⇒ V1): V1

def max[B >: (K, V)](implicit ord: Ordering[B]): (K, V)

def maxBy[B](f: ((K, V)) ⇒ B)(implicit cmp: Ordering[B]): (K, V)

def min[B >: (K, V)](implicit ord: Ordering[B]): (K, V)

def minBy[B](f: ((K, V)) ⇒ B)(implicit cmp: Ordering[B]): (K, V)

def product[B >: (K, V)](implicit num: Numeric[B]): B

def sum[B >: (K, V)](implicit num: Numeric[B]): B

Inherited from MapOps[K, V, Map, Map[K, V]]

Inherited from Shrinkable[K]

Inherited from collection.Map[K, V]

Inherited from collection.MapOps[K, V, Map, Map[K, V]]

Inherited from Equals

Inherited from PartialFunction[K, V]

Inherited from (K) ⇒ V

Inherited from Iterable[(K, V)]

Inherited from IterableOps[(K, V), Iterable, Map[K, V]]

Inherited from Growable[(K, V)]

Inherited from collection.Iterable[(K, V)]

Inherited from collection.IterableOps[(K, V), Iterable, Map[K, V]]

Inherited from IterableOnce[(K, V)]

Inherited from AnyRef

Inherited from Any

Ungrouped

Map