# Map

#### trait Map [A, +B] extends Iterable[(A, B)] with Map[A, B] with MapLike[A, B, Map[A, B]]

A generic trait for immutable maps. Concrete classes have to provide functionality for the abstract methods in `Map`:

```   def get(key: A): Option[B]
def iterator: Iterator[(A, B)]
def + [B1 >: B](kv: (A, B1)): Map[A, B1]
def -(key: A): Map[A, B]
```
go to: companion
linear super types: MapLike[A, B, Map[A, B]], Map[A, B], MapLike[A, B, Map[A, B]], Subtractable[A, Map[A, B]], PartialFunction[A, B], (A) ⇒ B, Iterable[(A, B)], Iterable[(A, B)], IterableLike[(A, B), Map[A, B]], Equals, Traversable[(A, B)], Immutable, Traversable[(A, B)], GenericTraversableTemplate[(A, B), Iterable], TraversableLike[(A, B), Map[A, B]], TraversableOnce[(A, B)], FilterMonadic[(A, B), Map[A, B]], HasNewBuilder[(A, B), Map[A, B]], AnyRef, Any
known subclasses: IntMap, ListMap, Node, HashMap, HashTrieMap, HashMap1, LongMap, SortedMap, MapProxy, TreeMap, Map4, Map3, Map2, Map1, EmptyMap, WithDefault, DefaultMap, EmptyMap
self type: Map[A, B]
source: Map.scala
since
1. 1

Ordering
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Inherited
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1. Map
2. MapLike
3. Map
4. MapLike
5. Subtractable
6. PartialFunction
7. Function1
8. Iterable
9. Iterable
10. IterableLike
11. Equals
12. Traversable
13. Immutable
14. Traversable
15. GenericTraversableTemplate
16. TraversableLike
17. TraversableOnce
19. HasNewBuilder
20. AnyRef
21. Any
Visibility
1. Public
2. All
Impl.
1. Concrete
2. Abstract

### Type Members

1. #### class DefaultKeySet extends Set[A]

The implementation class of the set returned by `keySet`.

2. #### class DefaultValuesIterable extends Iterable[B]

The implementation class of the iterable returned by `values`.

3. #### type Self = Map[A, B]

The type implementing this traversable

The type implementing this traversable

attributes: protected
definition classes: TraversableLike
4. #### class WithFilter extends FilterMonadic[A, Repr]

A class supporting filtered operations.

### Value Members

1. #### def != (arg0: AnyRef) : Boolean

attributes: final
definition classes: AnyRef
2. #### def != (arg0: Any) : Boolean

`o != arg0` is the same as `!(o == (arg0))`.

`o != arg0` is the same as `!(o == (arg0))`.

arg0

the object to compare against this object for dis-equality.

returns

`false` if the receiver object is equivalent to the argument; `true` otherwise.

attributes: final
definition classes: Any
3. #### def ## () : Int

attributes: final
definition classes: AnyRef → Any
4. #### def \$asInstanceOf [T0] () : T0

attributes: final
definition classes: AnyRef
5. #### def \$isInstanceOf [T0] () : Boolean

attributes: final
definition classes: AnyRef
6. #### def + [B1 >: B] (elem1: (A, B1), elem2: (A, B1), elems: (A, B1)*) : Map[A, B1]

Adds two or more elements to this collection and returns a new collection.

Adds two or more elements to this collection and returns a new collection.

B1

the type of the added values

elem1

elem2

elems

returns

A new map with the new bindings added to this map.

definition classes: MapLikeMapLike
7. #### def + [B1 >: B] (kv: (A, B1)) : Map[A, B1]

Add a key/value pair to this map, returning a new map.

Add a key/value pair to this map, returning a new map.

B1

the type of the value in the key/value pair.

kv

the key/value pair.

returns

A new map with the new binding added to this map.

attributes: abstract
definition classes: MapMapLikeMapLike
8. #### def ++ [B1 >: B] (xs: TraversableOnce[(A, B1)]) : Map[A, B1]

Adds a number of elements provided by a traversable object and returns a new collection with the added elements.

Adds a number of elements provided by a traversable object and returns a new collection with the added elements.

B1

the type of the added values

xs

the traversable object consisting of key-value pairs.

returns

a new immutable map with the bindings of this map and those from `xs`.

definition classes: MapLikeMapLike
9. #### def ++ (that: TraversableOnce[(A, B)]) : immutable.Map[(A, B)]

[use case] Concatenates this immutable map with the elements of a traversable collection.

[use case]

Concatenates this immutable map with the elements of a traversable collection.

that

the traversable to append.

returns

a new immutable map which contains all elements of this immutable map followed by all elements of `that`.

attributes: abstract
definition classes: TraversableLike
10. #### def ++ [B >: A, That] (that: TraversableOnce[B])(implicit bf: CanBuildFrom[Map[A, B], B, That]) : That

Concatenates this immutable map with the elements of a traversable collection.

Concatenates this immutable map with the elements of a traversable collection.

B

the element type of the returned collection.

That

the class of the returned collection. Where possible, `That` is the same class as the current collection class `Repr`, but this depends on the element type `B` being admissible for that class, which means that an implicit instance of type `CanBuildFrom[Repr, B, That]` is found.

that

the traversable to append.

bf

an implicit value of class `CanBuildFrom` which determines the result class `That` from the current representation type `Repr` and and the new element type `B`.

returns

a new collection of type `That` which contains all elements of this immutable map followed by all elements of `that`.

definition classes: TraversableLike
11. #### def - (elem1: A, elem2: A, elems: A*) : Map[A, B]

Creates a new immutable map from this immutable map with some elements removed.

Creates a new immutable map from this immutable map with some elements removed.

This method takes two or more elements to be removed. Another overloaded variant of this method handles the case where a single element is removed.

elem1

the first element to remove.

elem2

the second element to remove.

elems

the remaining elements to remove.

returns

a new immutable map that contains all elements of the current immutable map except one less occurrence of each of the given elements.

definition classes: Subtractable
12. #### def - (key: A) : Map[A, B]

[use case] Removes a key from this map, returning a new map.

[use case]

Removes a key from this map, returning a new map.

key

the key to be removed

returns

a new map without a binding for `key`

attributes: abstract
definition classes: MapLike
13. #### def - (key: A) : Map[A, B]

Removes a key from this map, returning a new map.

Removes a key from this map, returning a new map.

key

the key to be removed

returns

a new map without a binding for `key`

attributes: abstract
definition classes: MapLikeSubtractable
14. #### def -- (xs: TraversableOnce[A]) : Map[A, B]

Creates a new immutable map from this immutable map by removing all elements of another collection.

Creates a new immutable map from this immutable map by removing all elements of another collection.

returns

a new immutable map that contains all elements of the current immutable map except one less occurrence of each of the elements of `elems`.

definition classes: Subtractable
15. #### def /: [B] (z: B)(op: (B, (A, B)) ⇒ B) : B

Applies a binary operator to a start value and all elements of this immutable map, going left to right.

Applies a binary operator to a start value and all elements of this immutable map, going left to right.

Note: `/:` is alternate syntax for `foldLeft`; `z /: xs` is the same as `xs foldLeft z`.

Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

B

the result type of the binary operator.

z

the start value.

op

the binary operator.

returns

the result of inserting `op` between consecutive elements of this immutable map, going left to right with the start value `z` on the left: op(...op(op(z, x1), x2), ..., xn) where `x,,1,,, ..., x,,n,,` are the elements of this immutable map.

definition classes: TraversableOnce
16. #### def :\ [B] (z: B)(op: ((A, B), B) ⇒ B) : B

Applies a binary operator to all elements of this immutable map and a start value, going right to left.

Applies a binary operator to all elements of this immutable map and a start value, going right to left.

Note: `:\` is alternate syntax for `foldRight`; `xs :\ z` is the same as `xs foldRight z`.

Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

B

the result type of the binary operator.

z

the start value

op

the binary operator

returns

the result of inserting `op` between consecutive elements of this immutable map, going right to left with the start value `z` on the right: op(x1, op(x2, ... op(xn, z)...)) where `x,,1,,, ..., x,,n,,` are the elements of this immutable map.

definition classes: TraversableOnce
17. #### def == (arg0: AnyRef) : Boolean

`o == arg0` is the same as `if (o eq null) arg0 eq null else o.equals(arg0)`.

`o == arg0` is the same as `if (o eq null) arg0 eq null else o.equals(arg0)`.

arg0

the object to compare against this object for equality.

returns

`true` if the receiver object is equivalent to the argument; `false` otherwise.

attributes: final
definition classes: AnyRef
18. #### def == (arg0: Any) : Boolean

`o == arg0` is the same as `o.equals(arg0)`.

`o == arg0` is the same as `o.equals(arg0)`.

arg0

the object to compare against this object for equality.

returns

`true` if the receiver object is equivalent to the argument; `false` otherwise.

attributes: final
definition classes: Any
19. #### def addString (b: StringBuilder, start: String, sep: String, end: String) : StringBuilder

Appends all bindings of this map to a string builder using start, end, and separator strings.

Appends all bindings of this map to a string builder using start, end, and separator strings. The written text begins with the string `start` and ends with the string `end`. Inside, the string representations of all bindings of this map in the form of `key -> value` are separated by the string `sep`.

b

the builder to which strings are appended.

start

the starting string.

sep

the separator string.

end

the ending string.

returns

the string builder `b` to which elements were appended.

definition classes: MapLikeTraversableOnce
20. #### def addString (b: StringBuilder) : StringBuilder

Appends all elements of this immutable map to a string builder.

Appends all elements of this immutable map to a string builder. The written text consists of the string representations (w.r.t. the method `toString`) of all elements of this immutable map without any separator string.

b

the string builder to which elements are appended.

returns

the string builder `b` to which elements were appended.

definition classes: TraversableOnce
21. #### def addString (b: StringBuilder, sep: String) : StringBuilder

Appends all elements of this immutable map to a string builder using a separator string.

Appends all elements of this immutable map 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 immutable map, separated by the string `sep`.

b

the string builder to which elements are appended.

sep

the separator string.

returns

the string builder `b` to which elements were appended.

definition classes: TraversableOnce
22. #### def andThen [C] (k: (B) ⇒ C) : PartialFunction[A, C]

Composes this partial function with a transformation function that gets applied to results of this partial function.

Composes this partial function with a transformation function that gets applied to results of this partial function.

C

the result type of the transformation function.

k

the transformation function

returns

a partial function with the same domain as this partial function, which maps arguments `x` to `k(this(x))`.

definition classes: PartialFunctionFunction1
23. #### def apply (key: A) : B

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: MapLikeFunction1
24. #### def asInstanceOf [T0] : T0

This method is used to cast the receiver object to be of type `T0`.

This method is used to cast the receiver object to be of type `T0`.

Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression`1.asInstanceOf[String]` will throw a `ClassCastException` at runtime, while the expression`List(1).asInstanceOf[List[String]]` will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested typed.

returns

attributes: final
definition classes: Any
25. #### def canEqual (that: Any) : Boolean

Method called from equality methods, so that user-defined subclasses can refuse to be equal to other collections of the same kind.

Method called from equality methods, so that user-defined subclasses can refuse to be equal to other collections of the same kind.

that

The object with which this immutable map should be compared

returns

`true`, if this immutable map can possibly equal `that`, `false` otherwise. The test takes into consideration only the run-time types of objects but ignores their elements.

definition classes: IterableLikeEquals
26. #### def clone () : AnyRef

This method creates and returns a copy of the receiver object.

This method creates and returns a copy of the receiver object.

The default implementation of the `clone` method is platform dependent.

returns

a copy of the receiver object.

attributes: protected[lang]
definition classes: AnyRef
27. #### def collect [B] (pf: PartialFunction[(A, B), B]) : immutable.Map[B]

[use case] Builds a new collection by applying a partial function to all elements of this immutable map on which the function is defined.

[use case]

Builds a new collection by applying a partial function to all elements of this immutable map on which the function is defined.

B

the element type of the returned collection.

pf

the partial function which filters and maps the immutable map.

returns

a new immutable map resulting from applying the given partial function `pf` to each element on which it is defined and collecting the results. The order of the elements is preserved.

attributes: abstract
definition classes: TraversableLike
28. #### def collect [B, That] (pf: PartialFunction[(A, B), B])(implicit bf: CanBuildFrom[Map[A, B], B, That]) : That

Builds a new collection by applying a partial function to all elements of this immutable map on which the function is defined.

Builds a new collection by applying a partial function to all elements of this immutable map on which the function is defined.

B

the element type of the returned collection.

That

the class of the returned collection. Where possible, `That` is the same class as the current collection class `Repr`, but this depends on the element type `B` being admissible for that class, which means that an implicit instance of type `CanBuildFrom[Repr, B, That]` is found.

pf

the partial function which filters and maps the immutable map.

bf

an implicit value of class `CanBuildFrom` which determines the result class `That` from the current representation type `Repr` and and the new element type `B`.

returns

a new collection of type `That` resulting from applying the partial function `pf` to each element on which it is defined and collecting the results. The order of the elements is preserved.

definition classes: TraversableLike
29. #### def companion : GenericCompanion[Iterable]

The factory companion object that builds instances of class immutable.

The factory companion object that builds instances of class immutable.Map. (or its `Iterable` superclass where class immutable.Map is not a `Seq`.)

30. #### def compose [A] (g: (A) ⇒ A) : (A) ⇒ B

(f compose g)(x) == f(g(x))

(f compose g)(x) == f(g(x))

definition classes: Function1
31. #### def contains (key: A) : 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: MapLike
32. #### def copyToArray (xs: Array[(A, B)], start: Int, len: Int) : Unit

[use case] Copies elements of this immutable map to an array.

[use case]

Copies elements of this immutable map to an array. Fills the given array `xs` with at most `len` elements of this immutable map, starting at position `start`. Copying will stop once either the end of the current immutable map is reached, or the end of the array is reached, or `len` elements have been copied.

xs

the array to fill.

start

the starting index.

len

the maximal number of elements to copy.

attributes: abstract
definition classes: TraversableLike
33. #### def copyToArray [B >: A] (xs: Array[B], start: Int, len: Int) : Unit

Copies elements of this immutable map to an array.

Copies elements of this immutable map to an array. Fills the given array `xs` with at most `len` elements of this immutable map, starting at position `start`. Copying will stop once either the end of the current immutable map is reached, or the end of the array is reached, or `len` elements have been copied.

B

the type of the elements of the array.

xs

the array to fill.

start

the starting index.

len

the maximal number of elements to copy.

definition classes: IterableLikeTraversableLikeTraversableOnce
34. #### def copyToArray (xs: Array[(A, B)]) : Unit

[use case] Copies values of this immutable map to an array.

[use case]

Copies values of this immutable map to an array. Fills the given array `xs` with values of this immutable map. Copying will stop once either the end of the current immutable map is reached, or the end of the array is reached.

xs

the array to fill.

attributes: abstract
definition classes: TraversableOnce
35. #### def copyToArray [B >: A] (xs: Array[B]) : Unit

Copies values of this immutable map to an array.

Copies values of this immutable map to an array. Fills the given array `xs` with values of this immutable map. Copying will stop once either the end of the current immutable map is reached, or the end of the array is reached.

B

the type of the elements of the array.

xs

the array to fill.

definition classes: TraversableOnce
36. #### def copyToArray (xs: Array[(A, B)], start: Int) : Unit

[use case] Copies values of this immutable map to an array.

[use case]

Copies values of this immutable map to an array. Fills the given array `xs` with values of this immutable map, after skipping `start` values. Copying will stop once either the end of the current immutable map is reached, or the end of the array is reached.

xs

the array to fill.

start

the starting index.

attributes: abstract
definition classes: TraversableOnce
37. #### def copyToArray [B >: A] (xs: Array[B], start: Int) : Unit

Copies values of this immutable map to an array.

Copies values of this immutable map to an array. Fills the given array `xs` with values of this immutable map, after skipping `start` values. Copying will stop once either the end of the current immutable map is reached, or the end of the array is reached.

B

the type of the elements of the array.

xs

the array to fill.

start

the starting index.

definition classes: TraversableOnce
38. #### def copyToBuffer [B >: A] (dest: Buffer[B]) : Unit

Copies all elements of this immutable map to a buffer.

Copies all elements of this immutable map to a buffer.

dest

The buffer to which elements are copied.

definition classes: TraversableOnce
39. #### def count (p: ((A, B)) ⇒ Boolean) : Int

Counts the number of elements in the immutable map which satisfy a predicate.

Counts the number of elements in the immutable map which satisfy a predicate.

p

the predicate used to test elements.

returns

the number of elements satisfying the predicate `p`.

definition classes: TraversableOnce
40. #### def default (key: A) : B

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: MapLike
41. #### def drop (n: Int) : Map[A, B]

Selects all elements except first n ones.

Selects all elements except first n ones.

Note: might return different results for different runs, unless the underlying collection type is ordered.

n

the number of elements to drop from this immutable map.

returns

a immutable map consisting of all elements of this immutable map except the first `n` ones, or else the empty immutable map, if this immutable map has less than `n` elements.

definition classes: TraversableLike
42. #### def dropRight (n: Int) : Map[A, B]

Selects all elements except last n ones.

Selects all elements except last n ones.

Note: might return different results for different runs, unless the underlying collection type is ordered.

n

The number of elements to take

returns

a immutable map consisting of all elements of this immutable map except the first `n` ones, or else the empty immutable map, if this immutable map has less than `n` elements.

definition classes: IterableLike
43. #### def dropWhile (p: ((A, B)) ⇒ Boolean) : Map[A, B]

Drops longest prefix of elements that satisfy a predicate.

Drops longest prefix of elements that satisfy a predicate.

Note: might return different results for different runs, unless the underlying collection type is ordered.

p

The predicate used to test elements.

returns

the longest suffix of this immutable map whose first element does not satisfy the predicate `p`.

definition classes: TraversableLike
44. #### def elements : Iterator[(A, B)]

definition classes: IterableLike
deprecated:
1. use `iterator' instead`

45. #### def empty : Map[A, B]

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 `This`.

definition classes: MapMapMapLike
46. #### def eq (arg0: AnyRef) : Boolean

This method is used to test whether the argument (`arg0`) is a reference to the receiver object (`this`).

This method is used to test whether the argument (`arg0`) is a reference to the receiver object (`this`).

The `eq` method implements an [http://en.wikipedia.org/wiki/Equivalence_relation equivalence relation] on non-null instances of `AnyRef`: * It is reflexive: for any non-null instance `x` of type `AnyRef`, `x.eq(x)` returns `true`. * It is symmetric: for any non-null instances `x` and `y` of type `AnyRef`, `x.eq(y)` returns `true` if and only if `y.eq(x)` returns `true`. * It is transitive: for any non-null instances `x`, `y`, and `z` of type `AnyRef` if `x.eq(y)` returns `true` and `y.eq(z)` returns `true`, then `x.eq(z)` returns `true`.

Additionally, the `eq` method has three other properties. * It is consistent: for any non-null instances `x` and `y` of type `AnyRef`, multiple invocations of `x.eq(y)` consistently returns `true` or consistently returns `false`. * For any non-null instance `x` of type `AnyRef`, `x.eq(null)` and `null.eq(x)` returns `false`. * `null.eq(null)` returns `true`.

When overriding the `equals` or `hashCode` methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (`o1 eq o2`), they should be equal to each other (`o1 == o2`) and they should hash to the same value (`o1.hashCode == o2.hashCode`).

arg0

the object to compare against this object for reference equality.

returns

`true` if the argument is a reference to the receiver object; `false` otherwise.

attributes: final
definition classes: AnyRef
47. #### def equals (that: Any) : Boolean

Compares two maps structurally; i.

Compares two maps structurally; i.e. checks if all mappings contained in this map are also contained in the other map, and vice versa.

that

the other map

returns

`true` if both maps contain exactly the same mappings, `false` otherwise.

definition classes: MapLikeEquals → AnyRef → Any
48. #### def exists (p: ((A, B)) ⇒ Boolean) : Boolean

Tests whether a predicate holds for some of the elements of this immutable map.

Tests whether a predicate holds for some of the elements of this immutable map.

p

the predicate used to test elements.

returns

`true` if the given predicate `p` holds for some of the elements of this immutable map, otherwise `false`.

definition classes: IterableLikeTraversableLikeTraversableOnce
49. #### def filter (p: ((A, B)) ⇒ Boolean) : Map[A, B]

Selects all elements of this immutable map which satisfy a predicate.

Selects all elements of this immutable map which satisfy a predicate.

p

the predicate used to test elements.

returns

a new immutable map consisting of all elements of this immutable map that satisfy the given predicate `p`. The order of the elements is preserved.

definition classes: TraversableLike
50. #### def filterKeys (p: (A) ⇒ Boolean) : Map[A, B]

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: MapLikeMapLike
51. #### def filterNot (p: ((A, B)) ⇒ Boolean) : Map[A, B]

Returns a new map with all key/value pairs for which the predicate `p` returns `true`.

Returns a new map with all key/value pairs for which the predicate `p` returns `true`.

Note: This method works by successively removing elements fro which the predicate is false from this set. If removal is slow, or you expect that most elements of the set will be removed, you might consider using `filter` with a negated predicate instead.

p

A predicate over key-value pairs

returns

A new map containing elements not satisfying the predicate.

definition classes: MapLikeTraversableLike
52. #### def finalize () : Unit

This method is called by the garbage collector on the receiver object when garbage collection determines that there are no more references to the object.

This method is called by the garbage collector on the receiver object when garbage collection determines that there are no more references to the object.

The details of when and if the `finalize` method are invoked, as well as the interaction between `finalize`and non-local returns and exceptions, are all platform dependent.

attributes: protected[lang]
definition classes: AnyRef
53. #### def find (p: ((A, B)) ⇒ Boolean) : Option[(A, B)]

Finds the first element of the immutable map satisfying a predicate, if any.

Finds the first element of the immutable map satisfying a predicate, if any.

Note: might return different results for different runs, unless the underlying collection type is ordered.

p

the predicate used to test elements.

returns

an option value containing the first element in the immutable map that satisfies `p`, or `None` if none exists.

definition classes: IterableLikeTraversableLikeTraversableOnce
54. #### def first : (A, B)

definition classes: IterableLike
deprecated:
1. use `head' instead`

55. #### def firstOption : Option[(A, B)]

`None` if iterable is empty.

`None` if iterable is empty.

definition classes: IterableLike
deprecated:
1. use `headOption' instead`

56. #### def flatMap [B] (f: ((A, B)) ⇒ Traversable[B]) : immutable.Map[B]

[use case] Builds a new collection by applying a function to all elements of this immutable map and concatenating the results.

[use case]

Builds a new collection by applying a function to all elements of this immutable map and concatenating the results.

B

the element type of the returned collection.

f

the function to apply to each element.

returns

a new immutable map resulting from applying the given collection-valued function `f` to each element of this immutable map and concatenating the results.

attributes: abstract
definition classes: TraversableLike
57. #### def flatMap [B, That] (f: ((A, B)) ⇒ Traversable[B])(implicit bf: CanBuildFrom[Map[A, B], B, That]) : That

Builds a new collection by applying a function to all elements of this immutable map and concatenating the results.

Builds a new collection by applying a function to all elements of this immutable map and concatenating the results.

B

the element type of the returned collection.

That

the class of the returned collection. Where possible, `That` is the same class as the current collection class `Repr`, but this depends on the element type `B` being admissible for that class, which means that an implicit instance of type `CanBuildFrom[Repr, B, That]` is found.

f

the function to apply to each element.

bf

an implicit value of class `CanBuildFrom` which determines the result class `That` from the current representation type `Repr` and and the new element type `B`.

returns

a new collection of type `That` resulting from applying the given collection-valued function `f` to each element of this immutable map and concatenating the results.

58. #### def flatten [B] : immutable.Map[B]

[use case] Converts this immutable map of traversable collections into a immutable map in which all element collections are concatenated.

[use case]

Converts this immutable map of traversable collections into a immutable map in which all element collections are concatenated.

B

the type of the elements of each traversable collection.

returns

a new immutable map resulting from concatenating all element immutable maps.

attributes: abstract
definition classes: GenericTraversableTemplate
59. #### def flatten [B] (implicit asTraversable: ((A, B)) ⇒ Traversable[B]) : Iterable[B]

Converts this immutable map of traversable collections into a immutable map in which all element collections are concatenated.

Converts this immutable map of traversable collections into a immutable map in which all element collections are concatenated.

B

the type of the elements of each traversable collection.

asTraversable

an implicit conversion which asserts that the element type of this immutable map is a `Traversable`.

returns

a new immutable map resulting from concatenating all element immutable maps.

definition classes: GenericTraversableTemplate
60. #### def foldLeft [B] (z: B)(op: (B, (A, B)) ⇒ B) : B

Applies a binary operator to a start value and all elements of this immutable map, going left to right.

Applies a binary operator to a start value and all elements of this immutable map, going left to right.

Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

B

the result type of the binary operator.

z

the start value.

op

the binary operator.

returns

the result of inserting `op` between consecutive elements of this immutable map, going left to right with the start value `z` on the left: op(...op(z, x1), x2, ..., xn) where `x,,1,,, ..., x,,n,,` are the elements of this immutable map.

definition classes: TraversableOnce
61. #### def foldRight [B] (z: B)(op: ((A, B), B) ⇒ B) : B

Applies a binary operator to all elements of this immutable map and a start value, going right to left.

Applies a binary operator to all elements of this immutable map and a start value, going right to left.

Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

B

the result type of the binary operator.

z

the start value.

op

the binary operator.

returns

the result of inserting `op` between consecutive elements of this immutable map, going right to left with the start value `z` on the right: op(x1, op(x2, ... op(xn, z)...)) where `x,,1,,, ..., x,,n,,` are the elements of this immutable map.

definition classes: IterableLikeTraversableOnce
62. #### def forall (p: ((A, B)) ⇒ Boolean) : Boolean

Tests whether a predicate holds for all elements of this immutable map.

Tests whether a predicate holds for all elements of this immutable map.

p

the predicate used to test elements.

returns

`true` if the given predicate `p` holds for all elements of this immutable map, otherwise `false`.

definition classes: IterableLikeTraversableLikeTraversableOnce
63. #### def foreach (f: ((A, B)) ⇒ Unit) : Unit

[use case] Applies a function `f` to all elements of this immutable map.

[use case]

Applies a function `f` to all elements of this immutable map.

f

the function that is applied for its side-effect to every element. The result of function `f` is discarded.

attributes: abstract
definition classes: IterableLike
64. #### def foreach [U] (f: ((A, B)) ⇒ U) : Unit

Applies a function `f` to all elements of this immutable map.

Applies a function `f` to all elements of this immutable map.

Note: this method underlies the implementation of most other bulk operations. Subclasses should re-implement this method if a more efficient implementation exists.

U

the type parameter describing the result of function `f`. This result will always be ignored. Typically `U` is `Unit`, but this is not necessary.

f

the function that is applied for its side-effect to every element. The result of function `f` is discarded.

65. #### def genericBuilder [B] : Builder[B, Iterable[B]]

The generic builder that builds instances of immutable.

The generic builder that builds instances of immutable.Map at arbitrary element types.

definition classes: GenericTraversableTemplate
66. #### def get (key: A) : Option[B]

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.

attributes: abstract
definition classes: MapLike
67. #### def getClass () : java.lang.Class[_ <: java.lang.Object]

Returns a representation that corresponds to the dynamic class of the receiver object.

Returns a representation that corresponds to the dynamic class of the receiver object.

The nature of the representation is platform dependent.

returns

a representation that corresponds to the dynamic class of the receiver object.

attributes: final
definition classes: AnyRef
68. #### def getOrElse (key: A, default: ⇒ B) : B

[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.

attributes: abstract
definition classes: MapLike
69. #### def getOrElse [B1 >: B] (key: A, default: ⇒ B1) : B1

Returns the value associated with a key, or a default value if the key is not contained in the map.

Returns the value associated with a key, or a default value if the key is not contained in the map.

B1

the result type of the default computation.

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: MapLike
70. #### def groupBy [K] (f: ((A, B)) ⇒ K) : Map[K, Map[A, B]]

Partitions this immutable map into a map of immutable maps according to some discriminator function.

Partitions this immutable map into a map of immutable maps according to some discriminator function.

Note: this method is not re-implemented by views. This means when applied to a view it will always force the view and return a new immutable map.

K

the type of keys returned by the discriminator function.

f

the discriminator function.

returns

A map from keys to immutable maps such that the following invariant holds: (xs partition f)(k) = xs filter (x => f(x) == k) That is, every key `k` is bound to a immutable map of those elements `x` for which `f(x)` equals `k`.

definition classes: TraversableLike
71. #### def grouped (size: Int) : Iterator[Map[A, B]]

Partitions elements in fixed size immutable maps.

Partitions elements in fixed size immutable maps.

size

the number of elements per group

returns

An iterator producing immutable maps of size `size`, except the last will be truncated if the elements don't divide evenly.

definition classes: IterableLike
1. Iterator#grouped

72. #### def hasDefiniteSize : Boolean

Tests whether this immutable map is known to have a finite size.

Tests whether this immutable map 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.

Note: many collection methods will not work on collections of infinite sizes.

returns

`true` if this collection is known to have finite size, `false` otherwise.

definition classes: TraversableLikeTraversableOnce
73. #### def hashCode () : Int

Returns a hash code value for the object.

Returns a hash code value for the object.

The default hashing algorithm is platform dependent.

Note that it is allowed for two objects to have identical hash codes (`o1.hashCode.equals(o2.hashCode)`) yet not be equal (`o1.equals(o2)` returns `false`). A degenerate implementation could always return `0`. However, it is required that if two objects are equal (`o1.equals(o2)` returns `true`) that they have identical hash codes (`o1.hashCode.equals(o2.hashCode)`). Therefore, when overriding this method, be sure to verify that the behavior is consistent with the `equals` method.

returns

the hash code value for the object.

definition classes: MapLike → AnyRef → Any
74. #### def head : (A, B)

Selects the first element of this immutable map.

Selects the first element of this immutable map.

Note: might return different results for different runs, unless the underlying collection type is ordered.

returns

the first element of this immutable map.

definition classes: IterableLikeTraversableLike
75. #### def headOption : Option[(A, B)]

Optionally selects the first element.

Optionally selects the first element.

Note: might return different results for different runs, unless the underlying collection type is ordered.

returns

the first element of this immutable map if it is nonempty, `None` if it is empty.

definition classes: TraversableLike
76. #### def init : Map[A, B]

Selects all elements except the last.

Selects all elements except the last.

Note: might return different results for different runs, unless the underlying collection type is ordered.

returns

a immutable map consisting of all elements of this immutable map except the last one.

definition classes: TraversableLike
77. #### def isDefinedAt (key: A) : 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: MapLikePartialFunction
78. #### def isEmpty : Boolean

Tests whether the map is empty.

Tests whether the map is empty.

returns

`true` if the map does not contain any key/value binding, `false` otherwise.

definition classes: MapLikeIterableLikeTraversableLikeTraversableOnce
79. #### def isInstanceOf [T0] : Boolean

This method is used to test whether the dynamic type of the receiver object is `T0`.

This method is used to test whether the dynamic type of the receiver object is `T0`.

Note that the test result of the test is modulo Scala's erasure semantics. Therefore the expression`1.isInstanceOf[String]` will return `false`, while the expression `List(1).isInstanceOf[List[String]]` will return `true`. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested typed.

returns

`true` if the receiver object is an instance of erasure of type `T0`; `false` otherwise.

attributes: final
definition classes: Any
80. #### def isTraversableAgain : Boolean

Tests whether this immutable map can be repeatedly traversed.

Tests whether this immutable map can be repeatedly traversed.

returns

`true`

attributes: final
definition classes: TraversableLikeTraversableOnce
81. #### def iterator : Iterator[(A, B)]

Creates a new iterator over all key/value pairs of this map

Creates a new iterator over all key/value pairs of this map

returns

the new iterator

attributes: abstract
definition classes: MapLikeIterableLike
82. #### def keySet : Set[A]

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: MapLike
83. #### def keys : Iterable[A]

Creates an iterator for all keys.

Creates an iterator for all keys.

returns

an iterator over all keys.

definition classes: MapLike
84. #### def keysIterator : Iterator[A]

Creates an iterator for all keys.

Creates an iterator for all keys.

returns

an iterator over all keys.

definition classes: MapLike
85. #### def last : (A, B)

Selects the last element.

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 immutable map.

definition classes: TraversableLike
86. #### def lastOption : Option[(A, B)]

Optionally selects the last element.

Optionally selects the last element.

Note: might return different results for different runs, unless the underlying collection type is ordered.

returns

the last element of this immutable map\$ if it is nonempty, `None` if it is empty.

definition classes: TraversableLike
87. #### def lift : (A) ⇒ Option[B]

Turns this partial function into an plain function returning an `Option` result.

Turns this partial function into an 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.

definition classes: PartialFunction
88. #### def map [B] (f: ((A, B)) ⇒ B) : immutable.Map[B]

[use case] Builds a new collection by applying a function to all elements of this immutable map.

[use case]

Builds a new collection by applying a function to all elements of this immutable map.

B

the element type of the returned collection.

f

the function to apply to each element.

returns

a new immutable map resulting from applying the given function `f` to each element of this immutable map and collecting the results.

attributes: abstract
definition classes: TraversableLike
89. #### def map [B, That] (f: ((A, B)) ⇒ B)(implicit bf: CanBuildFrom[Map[A, B], B, That]) : That

Builds a new collection by applying a function to all elements of this immutable map.

Builds a new collection by applying a function to all elements of this immutable map.

B

the element type of the returned collection.

That

the class of the returned collection. Where possible, `That` is the same class as the current collection class `Repr`, but this depends on the element type `B` being admissible for that class, which means that an implicit instance of type `CanBuildFrom[Repr, B, That]` is found.

f

the function to apply to each element.

bf

an implicit value of class `CanBuildFrom` which determines the result class `That` from the current representation type `Repr` and and the new element type `B`.

returns

a new collection of type `That` resulting from applying the given function `f` to each element of this immutable map and collecting the results.

90. #### def mapElements [C] (f: (B) ⇒ C) : Map[A, C]

definition classes: MapLike
deprecated:
1. use `mapValues' instead`

91. #### def mapValues [C] (f: (B) ⇒ C) : Map[A, C]

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: MapLikeMapLike
92. #### def max : (A, B)

[use case] Finds the largest element.

[use case]

Finds the largest element.

returns

the largest element of this immutable map.

attributes: abstract
definition classes: TraversableOnce
93. #### def max [B >: A] (implicit cmp: Ordering[B]) : (A, B)

Finds the largest element.

Finds the largest element.

B

The type over which the ordering is defined.

cmp

An ordering to be used for comparing elements.

returns

the largest element of this immutable map with respect to the ordering `cmp`.

definition classes: TraversableOnce
94. #### def min : (A, B)

[use case] Finds the smallest element.

[use case]

Finds the smallest element.

returns

the smallest element of this immutable map

attributes: abstract
definition classes: TraversableOnce
95. #### def min [B >: A] (implicit cmp: Ordering[B]) : (A, B)

Finds the smallest element.

Finds the smallest element.

B

The type over which the ordering is defined.

cmp

An ordering to be used for comparing elements.

returns

the smallest element of this immutable map with respect to the ordering `cmp`.

definition classes: TraversableOnce
96. #### def mkString : String

Displays all elements of this immutable map in a string.

Displays all elements of this immutable map in a string.

returns

a string representation of this immutable map. In the resulting string the string representations (w.r.t. the method `toString`) of all elements of this immutable map follow each other without any separator string.

definition classes: TraversableOnce
97. #### def mkString (sep: String) : String

Displays all elements of this immutable map in a string using a separator string.

Displays all elements of this immutable map in a string using a separator string.

sep

the separator string.

returns

a string representation of this immutable map. In the resulting string the string representations (w.r.t. the method `toString`) of all elements of this immutable map are separated by the string `sep`.

definition classes: TraversableOnce
98. #### def mkString (start: String, sep: String, end: String) : String

Displays all elements of this immutable map in a string using start, end, and separator strings.

Displays all elements of this immutable map in a string using start, end, and separator strings.

start

the starting string.

sep

the separator string.

end

the ending string.

returns

a string representation of this immutable map. 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 immutable map are separated by the string `sep`.

definition classes: TraversableOnce
99. #### def ne (arg0: AnyRef) : Boolean

`o.ne(arg0)` is the same as `!(o.eq(arg0))`.

`o.ne(arg0)` is the same as `!(o.eq(arg0))`.

arg0

the object to compare against this object for reference dis-equality.

returns

`false` if the argument is not a reference to the receiver object; `true` otherwise.

attributes: final
definition classes: AnyRef
100. #### def newBuilder : Builder[(A, B), Map[A, B]]

A common implementation of `newBuilder` for all maps in terms of `empty`.

A common implementation of `newBuilder` for all maps in terms of `empty`. Overridden for mutable maps in `mutable.MapLike`.

attributes: protected[this]
definition classes: MapLikeTraversableLikeHasNewBuilder
101. #### def nonEmpty : Boolean

Tests whether the immutable map is not empty.

Tests whether the immutable map is not empty.

returns

`true` if the immutable map contains at least one element, `false` otherwise.

definition classes: TraversableOnce
102. #### def notify () : Unit

Wakes up a single thread that is waiting on the receiver object's monitor.

Wakes up a single thread that is waiting on the receiver object's monitor.

attributes: final
definition classes: AnyRef
103. #### def notifyAll () : Unit

Wakes up all threads that are waiting on the receiver object's monitor.

Wakes up all threads that are waiting on the receiver object's monitor.

attributes: final
definition classes: AnyRef
104. #### def orElse [A1 <: A, B1 >: B] (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.

Composes this partial function with a fallback partial function which gets applied where this partial function is not defined.

A1

the argument type of the fallback function

B1

the result type of the fallback function

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.

definition classes: PartialFunction
105. #### def partition (p: ((A, B)) ⇒ Boolean) : (Map[A, B], Map[A, B])

Partitions this immutable map in two immutable maps according to a predicate.

Partitions this immutable map in two immutable maps according to a predicate.

p

the predicate on which to partition.

returns

a pair of immutable maps: the first immutable map consists of all elements that satisfy the predicate `p` and the second immutable map consists of all elements that don't. The relative order of the elements in the resulting immutable maps is the same as in the original immutable map.

definition classes: TraversableLike
106. #### def product : (A, B)

[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 immutable map of numbers of type `Int`. Instead of `Int`, any other type `T` with an implicit `Numeric[T]` implementation can be used as element type of the immutable map and as result type of `product`. Examples of such types are: `Long`, `Float`, `Double`, `BigInt`.

attributes: abstract
definition classes: TraversableOnce
107. #### def product [B >: A] (implicit num: Numeric[B]) : B

Multiplies up the elements of this collection.

Multiplies up the elements of this collection.

B

the result type of the `*` operator.

num

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

returns

the product of all elements of this immutable map with respect to the `*` operator in `num`.

definition classes: TraversableOnce
108. #### def projection : IterableView[(A, B), Map[A, B]]

returns a projection that can be used to call non-strict `filter`,`map`, and `flatMap` methods that build projections of the collection.

returns a projection that can be used to call non-strict `filter`,`map`, and `flatMap` methods that build projections of the collection.

definition classes: IterableLike
deprecated:
1. use `view' instead`

109. #### def reduceLeft [B >: A] (op: (B, (A, B)) ⇒ B) : B

Applies a binary operator to all elements of this immutable map, going left to right.

Applies a binary operator to all elements of this immutable map, going left to right.

Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

B

the result type of the binary operator.

op

the binary operator.

returns

the result of inserting `op` between consecutive elements of this immutable map, going left to right: op(...(op(x1, x2), ... ) , xn) where `x,,1,,, ..., x,,n,,` are the elements of this immutable map.

definition classes: TraversableOnce
110. #### def reduceLeftOption [B >: A] (op: (B, (A, B)) ⇒ B) : Option[B]

Optionally applies a binary operator to all elements of this immutable map, going left to right.

Optionally applies a binary operator to all elements of this immutable map, going left to right.

Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

B

the result type of the binary operator.

op

the binary operator.

returns

an option value containing the result of `reduceLeft(op)` is this immutable map is nonempty, `None` otherwise.

definition classes: TraversableOnce
111. #### def reduceRight [B >: A] (op: ((A, B), B) ⇒ B) : B

Applies a binary operator to all elements of this immutable map, going right to left.

Applies a binary operator to all elements of this immutable map, going right to left.

Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

B

the result type of the binary operator.

op

the binary operator.

returns

the result of inserting `op` between consecutive elements of this immutable map, going right to left: op(x1, op(x2, ..., op(xn-1, xn)...)) where `x,,1,,, ..., x,,n,,` are the elements of this immutable map.

definition classes: IterableLikeTraversableOnce
112. #### def reduceRightOption [B >: A] (op: ((A, B), B) ⇒ B) : Option[B]

Optionally applies a binary operator to all elements of this immutable map, going right to left.

Optionally applies a binary operator to all elements of this immutable map, going right to left.

Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

B

the result type of the binary operator.

op

the binary operator.

returns

an option value containing the result of `reduceRight(op)` is this immutable map is nonempty, `None` otherwise.

definition classes: TraversableOnce
113. #### def repr : Map[A, B]

The collection of type immutable map underlying this `TraversableLike` object.

The collection of type immutable map underlying this `TraversableLike` object. By default this is implemented as the `TraversableLike` object itself, but this can be overridden.

definition classes: TraversableLike
114. #### def reversed : List[(A, B)]

attributes: protected[this]
definition classes: TraversableOnce
115. #### def sameElements (that: Iterable[(A, B)]) : Boolean

[use case] Checks if the other iterable collection contains the same elements in the same order as this immutable map.

[use case]

Checks if the other iterable collection contains the same elements in the same order as this immutable map.

that

the collection to compare with.

returns

`true`, if both collections contain the same elements in the same order, `false` otherwise.

attributes: abstract
definition classes: IterableLike
116. #### def sameElements [B >: A] (that: Iterable[B]) : Boolean

Checks if the other iterable collection contains the same elements in the same order as this immutable map.

Checks if the other iterable collection contains the same elements in the same order as this immutable map.

Note: might return different results for different runs, unless the underlying collection type is ordered.

B

the type of the elements of collection `that`.

that

the collection to compare with.

returns

`true`, if both collections contain the same elements in the same order, `false` otherwise.

definition classes: IterableLike
117. #### def scanLeft [B, That] (z: B)(op: (B, (A, B)) ⇒ B)(implicit bf: CanBuildFrom[Map[A, B], B, That]) : That

Produces a collection containing cummulative results of applying the operator going left to right.

Produces a collection containing cummulative results of applying the operator going left to right.

Note: might return different results for different runs, unless the underlying collection type is ordered.

B

the type of the elements in the resulting collection

That

the actual type of the resulting collection

z

the initial value

op

the binary operator applied to the intermediate result and the element

bf

an implicit value of class `CanBuildFrom` which determines the result class `That` from the current representation type `Repr` and and the new element type `B`.

returns

collection with intermediate results

definition classes: TraversableLike
118. #### def scanRight [B, That] (z: B)(op: ((A, B), B) ⇒ B)(implicit bf: CanBuildFrom[Map[A, B], B, That]) : That

Produces a collection containing cummulative results of applying the operator going right to left.

Produces a collection containing cummulative results of applying the operator going right to left.

Note: might return different results for different runs, unless the underlying collection type is ordered.

B

the type of the elements in the resulting collection

That

the actual type of the resulting collection

z

the initial value

op

the binary operator applied to the intermediate result and the element

bf

an implicit value of class `CanBuildFrom` which determines the result class `That` from the current representation type `Repr` and and the new element type `B`.

returns

collection with intermediate results

definition classes: TraversableLike
119. #### def size : Int

The size of this immutable map.

The size of this immutable map.

returns

the number of elements in this immutable map.

definition classes: TraversableOnce
120. #### def slice (from: Int, until: Int) : Map[A, B]

Selects an interval of elements.

Selects an interval of elements.

Note: `c.slice(from, to)` is equivalent to (but possibly more efficient than) `c.drop(from).take(to - from)`

Note: might return different results for different runs, unless the underlying collection type is ordered.

from

the index of the first returned element in this immutable map.

until

the index one past the last returned element in this immutable map.

returns

a immutable map containing the elements starting at index `from` and extending up to (but not including) index `until` of this immutable map.

definition classes: IterableLikeTraversableLike
121. #### def sliding [B >: A] (size: Int, step: Int) : Iterator[Map[A, B]]

definition classes: IterableLike
122. #### def sliding [B >: A] (size: Int) : Iterator[Map[A, B]]

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

returns

An iterator producing immutable maps of size `size`, except the last and the only element will be truncated if there are fewer elements than size.

definition classes: IterableLike
1. Iterator#sliding

123. #### def span (p: ((A, B)) ⇒ Boolean) : (Map[A, B], Map[A, B])

Splits this immutable map into a prefix/suffix pair according to a predicate.

Splits this immutable map into a prefix/suffix pair according to a predicate.

Note: `c span p` is equivalent to (but possibly more efficient than) `(c takeWhile p, c dropWhile p)`, provided the evaluation of the predicate `p` does not cause any side-effects.

Note: might return different results for different runs, unless the underlying collection type is ordered.

p

the test predicate

returns

a pair consisting of the longest prefix of this immutable map whose elements all satisfy `p`, and the rest of this immutable map.

definition classes: TraversableLike
124. #### def splitAt (n: Int) : (Map[A, B], Map[A, B])

Splits this immutable map into two at a given position.

Splits this immutable map into two at a given position. Note: `c splitAt n` is equivalent to (but possibly more efficient than) `(c take n, c drop n)`.

Note: might return different results for different runs, unless the underlying collection type is ordered.

n

the position at which to split.

returns

a pair of immutable maps consisting of the first `n` elements of this immutable map, and the other elements.

definition classes: TraversableLike
125. #### def stringPrefix : String

Defines the prefix of this object's `toString` representation.

Defines the prefix of this object's `toString` representation.

returns

a string representation which starts the result of `toString` applied to this immutable map. Unless overridden in subclasses, the string prefix of every map is `"Map"`.

definition classes: MapLikeTraversableLike
126. #### def sum : (A, B)

[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 immutable map of numbers of type `Int`. Instead of `Int`, any other type `T` with an implicit `Numeric[T]` implementation can be used as element type of the immutable map and as result type of `sum`. Examples of such types are: `Long`, `Float`, `Double`, `BigInt`.

attributes: abstract
definition classes: TraversableOnce
127. #### def sum [B >: A] (implicit num: Numeric[B]) : B

Sums up the elements of this collection.

Sums up the elements of this collection.

B

the result type of the `+` operator.

num

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

returns

the sum of all elements of this immutable map with respect to the `+` operator in `num`.

definition classes: TraversableOnce
128. #### def synchronized [T0] (arg0: T0) : T0

attributes: final
definition classes: AnyRef
129. #### def tail : Map[A, B]

Selects all elements except the first.

Selects all elements except the first.

Note: might return different results for different runs, unless the underlying collection type is ordered.

returns

a immutable map consisting of all elements of this immutable map except the first one.

definition classes: TraversableLike
130. #### def take (n: Int) : Map[A, B]

Selects first n elements.

Selects first n elements.

Note: might return different results for different runs, unless the underlying collection type is ordered.

n

Tt number of elements to take from this immutable map.

returns

a immutable map consisting only of the first `n` elements of this immutable map, or else the whole immutable map, if it has less than `n` elements.

definition classes: IterableLikeTraversableLike
131. #### def takeRight (n: Int) : Map[A, B]

Selects last n elements.

Selects last n elements.

Note: might return different results for different runs, unless the underlying collection type is ordered.

n

the number of elements to take

returns

a immutable map consisting only of the last `n` elements of this immutable map, or else the whole immutable map, if it has less than `n` elements.

definition classes: IterableLike
132. #### def takeWhile (p: ((A, B)) ⇒ Boolean) : Map[A, B]

Takes longest prefix of elements that satisfy a predicate.

Takes longest prefix of elements that satisfy a predicate.

Note: might return different results for different runs, unless the underlying collection type is ordered.

p

The predicate used to test elements.

returns

the longest prefix of this immutable map whose elements all satisfy the predicate `p`.

definition classes: IterableLikeTraversableLike
133. #### def thisCollection : Iterable[(A, B)]

The underlying collection seen as an instance of `immutable.Map`.

The underlying collection seen as an instance of `immutable.Map`. By default this is implemented as the current collection object itself, but this can be overridden.

attributes: protected[this]
definition classes: IterableLikeTraversableLike
134. #### def toArray : Array[(A, B)]

[use case] Converts this immutable map to an array.

[use case]

Converts this immutable map to an array.

returns

an array containing all elements of this immutable map. A `ClassManifest` must be available for the element type of this immutable map.

attributes: abstract
definition classes: TraversableOnce
135. #### def toArray [B >: A] (implicit arg0: ClassManifest[B]) : Array[B]

Converts this immutable map to an array.

Converts this immutable map to an array.

B

the type of the elements of the array. A `ClassManifest` for this type must be available.

returns

an array containing all elements of this immutable map.

definition classes: TraversableOnce
136. #### def toBuffer [B >: A] : Buffer[B]

Converts this immutable map to a mutable buffer.

Converts this immutable map to a mutable buffer.

returns

a buffer containing all elements of this immutable map.

definition classes: TraversableOnce
137. #### def toCollection (repr: Map[A, B]) : Iterable[(A, B)]

A conversion from collections of type `Repr` to `immutable.Map` objects.

A conversion from collections of type `Repr` to `immutable.Map` objects. By default this is implemented as just a cast, but this can be overridden.

attributes: protected[this]
definition classes: IterableLikeTraversableLike
138. #### def toIndexedSeq [B >: A] : IndexedSeq[B]

Converts this immutable map to an indexed sequence.

Converts this immutable map to an indexed sequence.

returns

an indexed sequence containing all elements of this immutable map.

definition classes: TraversableOnce
139. #### def toIterable : Iterable[(A, B)]

Converts this immutable map to an iterable collection.

Converts this immutable map to an iterable collection. Note that the choice of target `Iterable` is lazy in this default implementation as this `TraversableOnce` may be lazy and unevaluated (i.e. it may be an iterator which is only traversable once).

returns

an `Iterable` containing all elements of this immutable map.

definition classes: IterableLikeTraversableOnce
140. #### def toIterator : Iterator[(A, B)]

Returns an Iterator over the elements in this immutable map.

Returns an Iterator over the elements in this immutable map. Will return the same Iterator if this instance is already an Iterator.

returns

an Iterator containing all elements of this immutable map.

definition classes: TraversableLikeTraversableOnce
141. #### def toList : List[(A, B)]

Converts this immutable map to a list.

Converts this immutable map to a list.

returns

a list containing all elements of this immutable map.

definition classes: TraversableOnce
142. #### def toMap [T, U] (implicit ev: <:<[(A, B), (T, U)]) : Map[T, U]

Converts this immutable map to a map.

Converts this immutable map to a map. This method is unavailable unless the elements are members of Tuple2, each ((K, V)) becoming a key-value pair in the map. Duplicate keys will be overwritten by later keys: if this is an unordered collection, which key is in the resulting map is undefined.

returns

a map containing all elements of this immutable map.

definition classes: TraversableOnce
143. #### def toSeq : Seq[(A, B)]

Converts this immutable map to a sequence.

Converts this immutable map to a sequence.

returns

a sequence containing all the elements of this immutable map.

definition classes: IterableLikeTraversableOnce
144. #### def toSet [B >: A] : Set[B]

Converts this immutable map to a set.

Converts this immutable map to a set.

returns

a set containing all elements of this immutable map.

definition classes: TraversableOnce
145. #### def toStream : Stream[(A, B)]

Converts this immutable map to a stream.

Converts this immutable map to a stream.

returns

a stream containing all elements of this immutable map.

definition classes: IterableLikeTraversableLikeTraversableOnce
146. #### def toString () : String

Converts this immutable map to a string.

Converts this immutable map to a string.

returns

a string representation of this collection. By default this string consists of the `stringPrefix` of this immutable map, followed by all elements separated by commas and enclosed in parentheses.

definition classes: MapLikeTraversableLikeFunction1 → AnyRef → Any
147. #### def toTraversable : Traversable[(A, B)]

Converts this immutable map to an unspecified Traversable.

Converts this immutable map to an unspecified Traversable. Will return the same collection if this instance is already Traversable.

returns

a Traversable containing all elements of this immutable map.

definition classes: TraversableLikeTraversableOnce
148. #### def transform [C, That] (f: (A, B) ⇒ C)(implicit bf: CanBuildFrom[Map[A, B], (A, C), That]) : That

This function transforms all the values of mappings contained in this map with function `f`.

This function transforms all the values of mappings contained in this map with function `f`.

f

A function over keys and values

returns

the updated map

definition classes: MapLike
149. #### def transpose [B] (implicit asTraversable: ((A, B)) ⇒ Traversable[B]) : Iterable[Iterable[B]]

Transposes this immutable map of traversable collections into a immutable map of immutable maps.

Transposes this immutable map of traversable collections into a immutable map of immutable maps.

B

the type of the elements of each traversable collection.

asTraversable

an implicit conversion which asserts that the element type of this immutable map is a `Traversable`.

returns

a two-dimensional immutable map of immutable maps which has as nth row the nth column of this immutable map.

definition classes: GenericTraversableTemplate
150. #### def unzip [A1, A2] (implicit asPair: ((A, B)) ⇒ (A1, A2)) : (Iterable[A1], Iterable[A2])

Converts this immutable map of pairs into two collections of the first and second halfs of each pair.

Converts this immutable map of pairs into two collections of the first and second halfs of each pair.

asPair

an implicit conversion which asserts that the element type of this immutable map is a pair.

returns

a pair immutable maps, containing the first, respectively second half of each element pair of this immutable map.

definition classes: GenericTraversableTemplate
151. #### def update [B1 >: B] (key: A, value: B1) : Map[A, B1]

definition classes: MapLike
deprecated:
1. use `updated' instead`

152. #### def updated [B1 >: B] (key: A, value: B1) : Map[A, B1]

A new immutable map containing updating this map with a given key/value mapping.

A new immutable map containing updating this map with a given key/value mapping.

B1

the type of the added value

key

the key

value

the value

returns

A new map with the new key/value mapping

definition classes: MapLikeMapLike
153. #### def values : Iterable[B]

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: MapLike
154. #### def valuesIterator : Iterator[B]

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: MapLike
155. #### def view (from: Int, until: Int) : IterableView[(A, B), Map[A, B]]

Creates a non-strict view of a slice of this immutable map.

Creates a non-strict view of a slice of this immutable map.

Note: the difference between `view` and `slice` is that `view` produces a view of the current immutable map, whereas `slice` produces a new immutable map.

Note: `view(from, to)` is equivalent to `view.slice(from, to)`

Note: might return different results for different runs, unless the underlying collection type is ordered.

from

the index of the first element of the view

until

the index of the element following the view

returns

a non-strict view of a slice of this immutable map, starting at index `from` and extending up to (but not including) index `until`.

definition classes: IterableLikeTraversableLike
156. #### def view : IterableView[(A, B), Map[A, B]]

Creates a non-strict view of this immutable map.

Creates a non-strict view of this immutable map.

returns

a non-strict view of this immutable map.

definition classes: IterableLikeTraversableLike
157. #### def wait () : Unit

attributes: final
definition classes: AnyRef
158. #### def wait (arg0: Long, arg1: Int) : Unit

attributes: final
definition classes: AnyRef
159. #### def wait (arg0: Long) : Unit

attributes: final
definition classes: AnyRef
160. #### def withDefault [B1 >: B] (d: (A) ⇒ B1) : Map[A, B1]

The same map with a given default function !!! todo: move to general maps?

The same map with a given default function !!! todo: move to general maps?

161. #### def withDefaultValue [B1 >: B] (d: B1) : Map[A, B1]

The same map with a given default value

The same map with a given default value

162. #### def withFilter (p: ((A, B)) ⇒ Boolean) : FilterMonadic[(A, B), Map[A, B]]

Creates a non-strict filter of this immutable map.

Creates a non-strict filter of this immutable map.

Note: the difference between `c filter p` and `c withFilter p` is that the former creates a new collection, whereas the latter only restricts the domain of subsequent `map`, `flatMap`, `foreach`, and `withFilter` operations.

Note: might return different results for different runs, unless the underlying collection type is ordered.

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 immutable map which satisfy the predicate `p`.

163. #### def zip [B] (that: Iterable[B]) : immutable.Map[((A, B), B)]

[use case] Returns a immutable map formed from this immutable map and another iterable collection by combining corresponding elements in pairs.

[use case]

Returns a immutable map formed from this immutable map and another iterable collection by combining corresponding elements in pairs. If one of the two collections is longer than the other, its remaining elements are ignored.

B

the type of the second half of the returned pairs

that

The iterable providing the second half of each result pair

returns

a new immutable map containing pairs consisting of corresponding elements of this immutable map and `that`. The length of the returned collection is the minimum of the lengths of this immutable map and `that`.

attributes: abstract
definition classes: IterableLike
164. #### def zip [A1 >: A, B, That] (that: Iterable[B])(implicit bf: CanBuildFrom[Map[A, B], (A1, B), That]) : That

Returns a immutable map formed from this immutable map and another iterable collection by combining corresponding elements in pairs.

Returns a immutable map formed from this immutable map and another iterable collection by combining corresponding elements in pairs. If one of the two collections is longer than the other, its remaining elements are ignored.

Note: might return different results for different runs, unless the underlying collection type is ordered.

A1

the type of the first half of the returned pairs (this is always a supertype of the collection's element type `A`).

B

the type of the second half of the returned pairs

That

the class of the returned collection. Where possible, `That` is the same class as the current collection class `Repr`, but this depends on the element type `(A1, B)` being admissible for that class, which means that an implicit instance of type `CanBuildFrom[Repr, (A1, B), That]`. is found.

that

The iterable providing the second half of each result pair

bf

an implicit value of class `CanBuildFrom` which determines the result class `That` from the current representation type `Repr` and the new element type `(A1, B)`.

returns

a new collection of type `That` containing pairs consisting of corresponding elements of this immutable map and `that`. The length of the returned collection is the minimum of the lengths of this immutable map and `that`.

definition classes: IterableLike
165. #### def zipAll [B] (that: Iterable[B], thisElem: (A, B), thatElem: B) : immutable.Map[((A, B), B)]

[use case] Returns a immutable map formed from this immutable map and another iterable collection by combining corresponding elements in pairs.

[use case]

Returns a immutable map formed from this immutable map and another iterable collection by combining corresponding elements in pairs. If one of the two collections is shorter than the other, placeholder elements are used to extend the shorter collection to the length of the longer.

B

the type of the second half of the returned pairs

that

The iterable providing the second half of each result pair

thisElem

the element to be used to fill up the result if this immutable map is shorter than `that`.

thatElem

the element to be used to fill up the result if `that` is shorter than this immutable map.

returns

a new immutable map containing pairs consisting of corresponding elements of this immutable map and `that`. The length of the returned collection is the maximum of the lengths of this immutable map and `that`. If this immutable map is shorter than `that`, `thisElem` values are used to pad the result. If `that` is shorter than this immutable map, `thatElem` values are used to pad the result.

attributes: abstract
definition classes: IterableLike
166. #### def zipAll [B, A1 >: A, That] (that: Iterable[B], thisElem: A1, thatElem: B)(implicit bf: CanBuildFrom[Map[A, B], (A1, B), That]) : That

Returns a immutable map formed from this immutable map and another iterable collection by combining corresponding elements in pairs.

Returns a immutable map formed from this immutable map and another iterable collection by combining corresponding elements in pairs. If one of the two collections is shorter than the other, placeholder elements are used to extend the shorter collection to the length of the longer.

Note: might return different results for different runs, unless the underlying collection type is ordered.

that

the iterable providing the second half of each result pair

thisElem

the element to be used to fill up the result if this immutable map is shorter than `that`.

thatElem

the element to be used to fill up the result if `that` is shorter than this immutable map.

returns

a new collection of type `That` containing pairs consisting of corresponding elements of this immutable map and `that`. The length of the returned collection is the maximum of the lengths of this immutable map and `that`. If this immutable map is shorter than `that`, `thisElem` values are used to pad the result. If `that` is shorter than this immutable map, `thatElem` values are used to pad the result.

definition classes: IterableLike
167. #### def zipWithIndex : immutable.Map[((A, B), Int)]

[use case] Zips this immutable map with its indices.

[use case]

Zips this immutable map with its indices.

returns

A new immutable map containing pairs consisting of all elements of this immutable map paired with their index. Indices start at `0`. @example `List("a", "b", "c").zipWithIndex = List(("a", 0), ("b", 1), ("c", 2))`

attributes: abstract
definition classes: IterableLike
168. #### def zipWithIndex [A1 >: A, That] (implicit bf: CanBuildFrom[Map[A, B], (A1, Int), That]) : That

Zips this immutable map with its indices.

Zips this immutable map with its indices.

Note: might return different results for different runs, unless the underlying collection type is ordered.

A1

the type of the first half of the returned pairs (this is always a supertype of the collection's element type `A`).

That

the class of the returned collection. Where possible, `That` is the same class as the current collection class `Repr`, but this depends on the element type `(A1, Int)` being admissible for that class, which means that an implicit instance of type `CanBuildFrom[Repr, (A1, Int), That]`. is found.

returns

A new collection of type `That` containing pairs consisting of all elements of this immutable map paired with their index. Indices start at `0`.

definition classes: IterableLike