Trait scala.collection.mutable.MapProxy
trait MapProxy[A, B] extends Map[A, B] with MapProxyLike[A, B, Map[A, B]]
Type Members
class DefaultKeySet extends AbstractSet[K] with Set[K] with Serializable
The implementation class of the set returned by keySet
.
- Attributes
- protected
- Definition Classes
- MapLike
class DefaultValuesIterable extends AbstractIterable[V] with Iterable[V] with Serializable
The implementation class of the iterable returned by values
.
- Attributes
- protected
- Definition Classes
- MapLike
class FilteredKeys extends AbstractMap[K, V] with DefaultMap[K, V]
- Attributes
- protected
- Definition Classes
- MapLike
class MappedValues[W] extends AbstractMap[K, W] with DefaultMap[K, W]
- Attributes
- protected
- Definition Classes
- MapLike
class WithFilter extends FilterMonadic[A, Repr]
A class supporting filtered operations. Instances of this class are returned by method withFilter
.
- Definition Classes
- TraversableLike
type Self = Map[A, B]
The type implementing this traversable
- Attributes
- protected[this]
- Definition Classes
- TraversableLike
Concrete Value Members
final def !=(arg0: Any): Boolean
Test two objects for inequality.
- returns
true
if !(this == that), false otherwise.
- Definition Classes
- AnyRef → Any
final def ##(): Int
Equivalent to x.hashCode
except for boxed numeric types and null
. For numerics, it returns a hash value which is consistent with value equality: if two value type instances compare as true, then ## will produce the same hash value for each of them. For null
returns a hashcode where null.hashCode
throws a NullPointerException
.
- returns
a hash value consistent with ==
- Definition Classes
- AnyRef → Any
def +[B1 >: B](elem1: (A, B1), elem2: (A, B1), elems: (A, B1)*): MapProxy[A, B1]
Adds key/value pairs to this map, returning a new map.
This method takes two or more key/value pairs. Another overloaded variant of this method handles the case where a single key/value pair is added.
- returns
a new map with the given bindings added to this map
- Definition Classes
- MapProxy → MapProxyLike → MapLike → MapLike
def +[B1 >: B](kv: (A, B1)): Map[A, B1]
Adds a key/value pair to this map, returning a new map.
- kv
the key/value pair
- returns
a new map with the new binding added to this map
- Definition Classes
- MapProxy → MapProxyLike → MapLike → MapLike → GenMapLike
def ++[B1 >: B](xs: GenTraversableOnce[(A, B1)]): MapProxy[A, B1]
Adds all key/value pairs in a traversable collection to this map, returning a new map.
- xs
the collection containing the added key/value pairs
- returns
a new map with the given bindings added to this map
- Definition Classes
- MapProxy → MapProxyLike → MapLike → MapLike
def ++[B >: (A, B), That](xs: GenTraversableOnce[B])(implicit bf: CanBuildFrom[Map[A, B], B, That]): That
Returns a new traversable collection containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the traversable collection is the most specific superclass encompassing the element types of the two operands.
- 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 classRepr
, but this depends on the element typeB
being admissible for that class, which means that an implicit instance of typeCanBuildFrom[Repr, B, That]
is found.- bf
an implicit value of class
CanBuildFrom
which determines the result classThat
from the current representation typeRepr
and the new element typeB
.- returns
a new collection of type
That
which contains all elements of this traversable collection followed by all elements ofthat
.
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableLike
def ++:[B >: (A, B), That](that: collection.Traversable[B])(implicit bf: CanBuildFrom[Map[A, B], B, That]): That
As with ++
, returns a new collection containing the elements from the left operand followed by the elements from the right operand.
It differs from ++
in that the right operand determines the type of the resulting collection rather than the left one. Mnemonic: the COLon is on the side of the new COLlection type.
Example:
scala> val x = List(1) x: List[Int] = List(1) scala> val y = LinkedList(2) y: scala.collection.mutable.LinkedList[Int] = LinkedList(2) scala> val z = x ++: y z: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2)
This overload exists because: for the implementation of ++:
we should reuse that of ++
because many collections override it with more efficient versions.
Since TraversableOnce
has no ++
method, we have to implement that directly, but Traversable
and down can use the overload.
- 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 classRepr
, but this depends on the element typeB
being admissible for that class, which means that an implicit instance of typeCanBuildFrom[Repr, B, That]
is found.- that
the traversable to append.
- bf
an implicit value of class
CanBuildFrom
which determines the result classThat
from the current representation typeRepr
and the new element typeB
.- returns
a new collection of type
That
which contains all elements of this traversable collection followed by all elements ofthat
.
- Definition Classes
- TraversableLike
def ++:[B](that: TraversableOnce[B]): Map[B]
As with ++
, returns a new collection containing the elements from the left operand followed by the elements from the right operand.
It differs from ++
in that the right operand determines the type of the resulting collection rather than the left one. Mnemonic: the COLon is on the side of the new COLlection type.
Example:
scala> val x = List(1) x: List[Int] = List(1) scala> val y = LinkedList(2) y: scala.collection.mutable.LinkedList[Int] = LinkedList(2) scala> val z = x ++: y z: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2)
- B
the element type of the returned collection.
- that
the traversable to append.
- returns
a new mutable map which contains all elements of this mutable map followed by all elements of
that
.
- Definition Classes
- TraversableLike
def ++=(xs: TraversableOnce[(A, B)]): MapProxy.this.type
adds all elements produced by a TraversableOnce to this growable collection.
- xs
the TraversableOnce producing the elements to add.
- returns
the growable collection itself.
- Definition Classes
- Growable
def +=(kv: (A, B)): MapProxy.this.type
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.
- kv
the key/value pair.
- returns
the map itself
def +=(elem1: (A, B), elem2: (A, B), elems: (A, B)*): MapProxy.this.type
adds two or more elements to this growable collection.
- elem1
the first element to add.
- elem2
the second element to add.
- elems
the remaining elements to add.
- returns
the growable collection itself
- Definition Classes
- Growable
def -(key: A): MapProxy[A, B]
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
- Definition Classes
- MapProxy → MapProxyLike → MapLike → MapLike → Subtractable → GenMapLike
def -(elem1: A, elem2: A, elems: A*): Map[A, B]
Creates a new map with all the key/value mappings of this map except mappings with keys equal to any of the two or more specified keys.
- elem1
the first element to remove.
- elem2
the second element to remove.
- elems
the remaining elements to remove.
- returns
a new map containing all the mappings of this map except mappings with a key equal to
elem1
,elem2
or any ofelems
.
- Definition Classes
- MapLike → Subtractable
- Annotations
- @migration
- Migration
(Changed in version 2.8.0)
-
creates a new map. Use-=
to remove an element from this map and return that map itself.
def --(xs: GenTraversableOnce[A]): Map[A, B]
Creates a new map with all the key/value mappings of this map except mappings with keys equal to any of those provided by the specified traversable object.
- xs
the traversable object.
- returns
a new map with all the key/value mappings of this map except mappings with a key equal to a key from
xs
.
- Definition Classes
- MapLike → Subtractable
- Annotations
- @migration
- Migration
(Changed in version 2.8.0)
--
creates a new map. Use--=
to remove an element from this map and return that map itself.
def --=(xs: TraversableOnce[A]): MapProxy.this.type
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 -=(key: A): MapProxy.this.type
Removes a key from this map.
- key
the key to be removed
- returns
the map itself.
- Definition Classes
- MapProxy → MapLike → Shrinkable
def -=(elem1: A, elem2: A, elems: A*): MapProxy.this.type
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 ->[B](y: B): (MapProxy[A, B], B)
- Implicit
- This member is added by an implicit conversion from MapProxy[A, B] to ArrowAssoc[MapProxy[A, B]] performed by method ArrowAssoc in scala.Predef.
- Definition Classes
- ArrowAssoc
- Annotations
- @inline()
def /:[B](z: B)(op: (B, (A, B)) ⇒ B): B
Applies a binary operator to a start value and all elements of this traversable collection, going left to right.
Note: /:
is alternate syntax for foldLeft
; z /: xs
is the same as xs foldLeft z
.
Examples:
Note that the folding function used to compute b is equivalent to that used to compute c.
scala> val a = List(1,2,3,4) a: List[Int] = List(1, 2, 3, 4) scala> val b = (5 /: a)(_+_) b: Int = 15 scala> val c = (5 /: a)((x,y) => x + y) c: Int = 15
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.
- B
the result type of the binary operator.
- z
the start value.
- op
the binary operator.
- returns
-
the result of inserting
op
between consecutive elements of this traversable collection, going left to right with the start valuez
on the left:op(...op(op(z, x_1), x_2), ..., x_n)
where
x1, ..., xn
are the elements of this traversable collection.
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
def :\[B](z: B)(op: ((A, B), B) ⇒ B): B
Applies a binary operator to all elements of this traversable collection and a start value, going right to left.
Note: :\
is alternate syntax for foldRight
; xs :\ z
is the same as xs foldRight z
.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.
Examples:
Note that the folding function used to compute b is equivalent to that used to compute c.
scala> val a = List(1,2,3,4) a: List[Int] = List(1, 2, 3, 4) scala> val b = (a :\ 5)(_+_) b: Int = 15 scala> val c = (a :\ 5)((x,y) => x + y) c: Int = 15
- 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 traversable collection, going right to left with the start valuez
on the right:op(x_1, op(x_2, ... op(x_n, z)...))
where
x1, ..., xn
are the elements of this traversable collection.
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
final def ==(arg0: Any): Boolean
The expression x == that
is equivalent to if (x eq null) that eq null else x.equals(that)
.
- returns
true
if the receiver object is equivalent to the argument;false
otherwise.
- Definition Classes
- AnyRef → Any
def addString(b: scala.StringBuilder, start: String, sep: String, end: String): scala.StringBuilder
Appends all elements 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 (w.r.t. the method toString
) of all elements of this map are separated by the string sep
.
Example:
scala> val a = List(1,2,3,4) a: List[Int] = List(1, 2, 3, 4) scala> val b = new StringBuilder() b: StringBuilder = scala> a.addString(b , "List(" , ", " , ")") res5: StringBuilder = List(1, 2, 3, 4)
- b
the string builder to which elements are appended.
- start
the starting string.
- sep
the separator string.
- end
the ending string.
- returns
the string builder
b
to which elements were appended.
- Definition Classes
- MapProxyLike → TraversableProxyLike → MapLike → TraversableOnce
def addString(b: StringBuilder): StringBuilder
Appends all elements of this traversable collection to a string builder. The written text consists of the string representations (w.r.t. the method toString
) of all elements of this traversable collection without any separator string.
Example:
scala> val a = List(1,2,3,4) a: List[Int] = List(1, 2, 3, 4) scala> val b = new StringBuilder() b: StringBuilder = scala> val h = a.addString(b) h: StringBuilder = 1234
- b
the string builder to which elements are appended.
- returns
the string builder
b
to which elements were appended.
- Definition Classes
- TraversableProxyLike → TraversableOnce
def addString(b: StringBuilder, sep: String): StringBuilder
Appends all elements of this traversable collection to a string builder using a separator string. The written text consists of the string representations (w.r.t. the method toString
) of all elements of this traversable collection, separated by the string sep
.
Example:
scala> val a = List(1,2,3,4) a: List[Int] = List(1, 2, 3, 4) scala> val b = new StringBuilder() b: StringBuilder = scala> a.addString(b, ", ") res0: StringBuilder = 1, 2, 3, 4
- b
the string builder to which elements are appended.
- sep
the separator string.
- returns
the string builder
b
to which elements were appended.
- Definition Classes
- TraversableProxyLike → TraversableOnce
def aggregate[B](z: ⇒ B)(seqop: (B, (A, B)) ⇒ B, combop: (B, B) ⇒ B): B
Aggregates the results of applying an operator to subsequent elements.
This is a more general form of fold
and reduce
. It is similar to foldLeft
in that it doesn't require the result to be a supertype of the element type. In addition, it allows parallel collections to be processed in chunks, and then combines the intermediate results.
aggregate
splits the traversable or iterator into partitions and processes each partition by sequentially applying seqop
, starting with z
(like foldLeft
). Those intermediate results are then combined by using combop
(like fold
). The implementation of this operation may operate on an arbitrary number of collection partitions (even 1), so combop
may be invoked an arbitrary number of times (even 0).
As an example, consider summing up the integer values of a list of chars. The initial value for the sum is 0. First, seqop
transforms each input character to an Int and adds it to the sum (of the partition). Then, combop
just needs to sum up the intermediate results of the partitions:
List('a', 'b', 'c').aggregate(0)({ (sum, ch) => sum + ch.toInt }, { (p1, p2) => p1 + p2 })
- B
the type of accumulated results
- z
the initial value for the accumulated result of the partition - this will typically be the neutral element for the
seqop
operator (e.g.Nil
for list concatenation or0
for summation) and may be evaluated more than once- seqop
an operator used to accumulate results within a partition
- combop
an associative operator used to combine results from different partitions
- Definition Classes
- TraversableOnce → GenTraversableOnce
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.
- 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
tok(this(x))
.
- Definition Classes
- PartialFunction → Function1
def apply(key: A): B
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
- MapProxyLike → MapLike → GenMapLike → Function1
def applyOrElse[K1 <: A, V1 >: B](x: K1, default: (K1) ⇒ V1): V1
Applies this partial function to the given argument when it is contained in the function domain. Applies fallback function where this partial function is not defined.
Note that expression pf.applyOrElse(x, default)
is equivalent to
if(pf isDefinedAt x) pf(x) else default(x)
except that applyOrElse
method can be implemented more efficiently. For all partial function literals the compiler generates an applyOrElse
implementation which avoids double evaluation of pattern matchers and guards. This makes applyOrElse
the basis for the efficient implementation for many operations and scenarios, such as:
-
combining partial functions into
orElse
/andThen
chains does not lead to excessive apply
/isDefinedAt
evaluation
lift
and unlift
do not evaluate source functions twice on each invocation
runWith
allows efficient imperative-style combining of partial functions with conditionally applied actions For non-literal partial function classes with nontrivial isDefinedAt
method it is recommended to override applyOrElse
with custom implementation that avoids double isDefinedAt
evaluation. This may result in better performance and more predictable behavior w.r.t. side effects.
- x
the function argument
- default
the fallback function
- returns
the result of this function or fallback function application.
- Definition Classes
- MapLike → PartialFunction
- Since
2.10
final def asInstanceOf[T0]: T0
Cast the receiver object to be of type T0
.
Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression 1.asInstanceOf[String]
will throw a ClassCastException
at runtime, while the expression List(1).asInstanceOf[List[String]]
will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested type.
- returns
the receiver object.
- Definition Classes
- Any
- Exceptions thrown
ClassCastException
if the receiver object is not an instance of the erasure of typeT0
.
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.
- that
The object with which this iterable collection should be compared
- returns
true
, if this iterable collection can possibly equalthat
,false
otherwise. The test takes into consideration only the run-time types of objects but ignores their elements.
- Definition Classes
- IterableLike → Equals
def clear(): Unit
Removes all bindings from the map. After this operation has completed, the map will be empty.
def clone(): Map[A, B]
Create a copy of the receiver object.
The default implementation of the clone
method is platform dependent.
- returns
a copy of the receiver object.
def collect[B](pf: PartialFunction[A, B]): Map[B]
Builds a new collection by applying a partial function to all elements of this mutable map on which the function is defined.
- B
the element type of the returned collection.
- pf
the partial function which filters and maps the mutable map.
- returns
a new mutable 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.
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableLike
def collectFirst[B](pf: PartialFunction[(A, B), B]): Option[B]
Finds the first element of the traversable or iterator for which the given partial function is defined, and applies the partial function to it.
Note: may not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- pf
the partial function
- returns
an option value containing pf applied to the first value for which it is defined, or
None
if none exists.
- Definition Classes
- TraversableOnce
Seq("a", 1, 5L).collectFirst({ case x: Int => x*10 }) = Some(10)
def companion: GenericCompanion[Iterable]
The factory companion object that builds instances of class Iterable. (or its Iterable
superclass where class Iterable is not a Seq
.)
- Definition Classes
- Iterable → Iterable → GenIterable → Traversable → Traversable → GenTraversable → GenericTraversableTemplate
def compose[A](g: (A) ⇒ A): (A) ⇒ B
Composes two instances of Function1 in a new Function1, with this function applied last.
- A
the type to which function
g
can be applied- g
a function A => T1
- returns
a new function
f
such thatf(x) == apply(g(x))
- Definition Classes
- Function1
- Annotations
- @unspecialized()
def contains(key: A): Boolean
Tests whether this map contains a binding for a key.
- key
the key
- returns
true
if there is a binding forkey
in this map,false
otherwise.
- Definition Classes
- MapProxyLike → MapLike → GenMapLike
def copyToArray(xs: Array[A]): Unit
Copies the elements of this mutable map to an array. Fills the given array xs
with values of this mutable map. Copying will stop once either the end of the current mutable map is reached, or the end of the target array is reached.
- xs
the array to fill.
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
def copyToArray(xs: Array[A], start: Int): Unit
Copies the elements of this mutable map to an array. Fills the given array xs
with values of this mutable map, beginning at index start
. Copying will stop once either the end of the current mutable map is reached, or the end of the target array is reached.
- xs
the array to fill.
- start
the starting index.
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
def copyToArray(xs: Array[A], start: Int, len: Int): Unit
Copies the elements of this mutable map to an array. Fills the given array xs
with at most len
elements of this mutable map, starting at position start
. Copying will stop once either the end of the current mutable map is reached, or the end of the target 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.
- Definition Classes
- TraversableProxyLike → TraversableLike → TraversableOnce → GenTraversableOnce
def copyToBuffer[B >: (A, B)](dest: Buffer[B]): Unit
Copies all elements of this traversable collection to a buffer.
Note: will not terminate for infinite-sized collections.
- dest
The buffer to which elements are copied.
- Definition Classes
- TraversableProxyLike → TraversableOnce
def count(p: ((A, B)) ⇒ Boolean): Int
Counts the number of elements in the traversable collection which satisfy a predicate.
- p
the predicate used to test elements.
- returns
the number of elements satisfying the predicate
p
.
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
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.
- key
the given key value for which a binding is missing.
- Definition Classes
- MapProxyLike → MapLike → GenMapLike
- Exceptions thrown
def drop(n: Int): Map[A, B]
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 traversable collection.
- returns
a traversable collection consisting of all elements of this traversable collection except the first
n
ones, or else the empty traversable collection, if this traversable collection has less thann
elements. Ifn
is negative, don't drop any elements.
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableLike
def dropRight(n: Int): Map[A, B]
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 iterable collection consisting of all elements of this iterable collection except the last
n
ones, or else the empty iterable collection, if this iterable collection has less thann
elements.
- Definition Classes
- IterableProxyLike → IterableLike
def dropWhile(p: ((A, B)) ⇒ Boolean): Map[A, B]
Drops longest prefix of elements that satisfy a predicate.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- returns
the longest suffix of this traversable collection whose first element does not satisfy the predicate
p
.
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableLike
def empty: MapProxy[A, B]
The empty map of the same type as this map
- returns
an empty map of type
This
.
def ensuring(cond: (MapProxy[A, B]) ⇒ Boolean, msg: ⇒ Any): MapProxy[A, B]
- Implicit
- This member is added by an implicit conversion from MapProxy[A, B] to Ensuring[MapProxy[A, B]] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
def ensuring(cond: (MapProxy[A, B]) ⇒ Boolean): MapProxy[A, B]
- Implicit
- This member is added by an implicit conversion from MapProxy[A, B] to Ensuring[MapProxy[A, B]] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
def ensuring(cond: Boolean, msg: ⇒ Any): MapProxy[A, B]
- Implicit
- This member is added by an implicit conversion from MapProxy[A, B] to Ensuring[MapProxy[A, B]] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
def ensuring(cond: Boolean): MapProxy[A, B]
- Implicit
- This member is added by an implicit conversion from MapProxy[A, B] to Ensuring[MapProxy[A, B]] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
final def eq(arg0: AnyRef): Boolean
Tests whether the argument (that
) is a reference to the receiver object (this
).
The eq
method implements an equivalence relation on non-null instances of AnyRef
, and has three additional 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
).
- returns
true
if the argument is a reference to the receiver object;false
otherwise.
- Definition Classes
- AnyRef
def equals(that: Any): Boolean
Compares the receiver object (this
) with the argument object (that
) for equivalence.
Any implementation of this method should be an equivalence relation:
-
It is reflexive: for any instance
x
of type Any
, x.equals(x)
should return true
.It is symmetric: for any instances x
and y
of type Any
, x.equals(y)
should return true
if and only if y.equals(x)
returns true
.It is transitive: for any instances x
, y
, and z
of type Any
if x.equals(y)
returns true
and y.equals(z)
returns true
, then x.equals(z)
should return true
. If you override this method, you should verify that your implementation remains an equivalence relation. Additionally, when overriding this method it is usually necessary to override hashCode
to ensure that objects which are "equal" (o1.equals(o2)
returns true
) hash to the same scala.Int. (o1.hashCode.equals(o2.hashCode)
).
- that
the object to compare against this object for equality.
- returns
true
if the receiver object is equivalent to the argument;false
otherwise.
def exists(p: ((A, B)) ⇒ Boolean): Boolean
Tests whether a predicate holds for at least one element of this traversable collection.
Note: may not terminate for infinite-sized collections.
- p
the predicate used to test elements.
- returns
false
if this traversable collection is empty, otherwisetrue
if the given predicatep
holds for some of the elements of this traversable collection, otherwisefalse
- Definition Classes
- TraversableProxyLike → TraversableLike → TraversableOnce → GenTraversableOnce
def filter(p: ((A, B)) ⇒ Boolean): Map[A, B]
Selects all elements of this traversable collection which satisfy a predicate.
- p
the predicate used to test elements.
- returns
a new traversable collection consisting of all elements of this traversable collection that satisfy the given predicate
p
. The order of the elements is preserved.
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableLike
def filterKeys(p: (A) ⇒ Boolean): collection.Map[A, B]
Filters this map by retaining only keys satisfying a predicate.
Note: the predicate must accept any key of type K
, not just those already present in the map, as the predicate is tested before the underlying map is queried.
- 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
- MapProxyLike → MapLike → GenMapLike
def filterNot(p: ((A, B)) ⇒ Boolean): Map[A, B]
Selects all elements of this map which do not satisfy a predicate.
- p
the predicate used to test elements.
- returns
a new map consisting of all elements of this map that do not satisfy the given predicate
p
. The order of the elements is preserved.
- Definition Classes
- MapProxyLike → TraversableProxyLike → MapLike → TraversableLike → GenTraversableLike
def finalize(): Unit
Called by the garbage collector on the receiver object when there are no more references to the object.
The details of when and if the finalize
method is invoked, as well as the interaction between finalize
and non-local returns and exceptions, are all platform dependent.
- Attributes
- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws( classOf[java.lang.Throwable] )
- Note
not specified by SLS as a member of AnyRef
def find(p: ((A, B)) ⇒ Boolean): Option[(A, B)]
Finds the first element of the traversable collection satisfying a predicate, if any.
Note: may not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- p
the predicate used to test elements.
- returns
an option value containing the first element in the traversable collection that satisfies
p
, orNone
if none exists.
- Definition Classes
- TraversableProxyLike → TraversableLike → TraversableOnce → GenTraversableOnce
def flatMap[B](f: (A) ⇒ GenTraversableOnce[B]): Map[B]
Builds a new collection by applying a function to all elements of this mutable map and using the elements of the resulting collections.
For example:
def getWords(lines: Seq[String]): Seq[String] = lines flatMap (line => line split "\\W+")
The type of the resulting collection is guided by the static type of mutable map. This might cause unexpected results sometimes. For example:
// lettersOf will return a Seq[Char] of likely repeated letters, instead of a Set def lettersOf(words: Seq[String]) = words flatMap (word => word.toSet) // lettersOf will return a Set[Char], not a Seq def lettersOf(words: Seq[String]) = words.toSet flatMap (word => word.toSeq) // xs will be an Iterable[Int] val xs = Map("a" -> List(11,111), "b" -> List(22,222)).flatMap(_._2) // ys will be a Map[Int, Int] val ys = Map("a" -> List(1 -> 11,1 -> 111), "b" -> List(2 -> 22,2 -> 222)).flatMap(_._2)
- B
the element type of the returned collection.
- f
the function to apply to each element.
- returns
a new mutable map resulting from applying the given collection-valued function
f
to each element of this mutable map and concatenating the results.
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableLike → FilterMonadic
def flatten[B]: Map[B]
Converts this mutable map of traversable collections into a mutable map formed by the elements of these traversable collections.
The resulting collection's type will be guided by the static type of mutable map. For example:
val xs = List( Set(1, 2, 3), Set(1, 2, 3) ).flatten // xs == List(1, 2, 3, 1, 2, 3) val ys = Set( List(1, 2, 3), List(3, 2, 1) ).flatten // ys == Set(1, 2, 3)
- B
the type of the elements of each traversable collection.
- returns
a new mutable map resulting from concatenating all element mutable maps.
- Definition Classes
- GenericTraversableTemplate
def fold[A1 >: (A, B)](z: A1)(op: (A1, A1) ⇒ A1): A1
Folds the elements of this traversable or iterator using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
Note: will not terminate for infinite-sized collections.
- A1
a type parameter for the binary operator, a supertype of
A
.- z
a neutral element for the fold operation; may be added to the result an arbitrary number of times, and must not change the result (e.g.,
Nil
for list concatenation, 0 for addition, or 1 for multiplication).- op
a binary operator that must be associative.
- returns
the result of applying the fold operator
op
between all the elements andz
, orz
if this traversable or iterator is empty.
- Definition Classes
- TraversableOnce → GenTraversableOnce
def foldLeft[B](z: B)(op: (B, (A, B)) ⇒ B): B
Applies a binary operator to a start value and all elements of this traversable collection, going left to right.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.
- B
the result type of the binary operator.
- z
the start value.
- op
the binary operator.
- returns
-
the result of inserting
op
between consecutive elements of this traversable collection, going left to right with the start valuez
on the left:op(...op(z, x_1), x_2, ..., x_n)
where
x1, ..., xn
are the elements of this traversable collection. Returnsz
if this traversable collection is empty.
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
def foldRight[B](z: B)(op: ((A, B), B) ⇒ B): B
Applies a binary operator to all elements of this traversable collection and a start value, going right to left.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.
- B
the result type of the binary operator.
- z
the start value.
- op
the binary operator.
- returns
-
the result of inserting
op
between consecutive elements of this traversable collection, going right to left with the start valuez
on the right:op(x_1, op(x_2, ... op(x_n, z)...))
where
x1, ..., xn
are the elements of this traversable collection. Returnsz
if this traversable collection is empty.
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
def forall(p: ((A, B)) ⇒ Boolean): Boolean
Tests whether a predicate holds for all elements of this traversable collection.
Note: may not terminate for infinite-sized collections.
- p
the predicate used to test elements.
- returns
true
if this traversable collection is empty or the given predicatep
holds for all elements of this traversable collection, otherwisefalse
.
- Definition Classes
- TraversableProxyLike → TraversableLike → TraversableOnce → GenTraversableOnce
def foreach(f: (A) ⇒ Unit): Unit
Applies a function f
to all elements of this mutable map.
Note: this method underlies the implementation of most other bulk operations. It's important to implement this method in an efficient way.
- f
the function that is applied for its side-effect to every element. The result of function
f
is discarded.
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableLike → TraversableOnce → GenTraversableOnce → FilterMonadic
def formatted(fmtstr: String): String
Returns string formatted according to given format
string. Format strings are as for String.format
(@see java.lang.String.format).
- Implicit
- This member is added by an implicit conversion from MapProxy[A, B] to StringFormat[MapProxy[A, B]] performed by method StringFormat in scala.Predef.
- Definition Classes
- StringFormat
- Annotations
- @inline()
def genericBuilder[B]: Builder[B, Iterable[B]]
The generic builder that builds instances of Traversable at arbitrary element types.
- Definition Classes
- GenericTraversableTemplate
def get(key: A): Option[B]
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, orNone
if none exists.
- Definition Classes
- MapProxyLike → MapLike → GenMapLike
final def getClass(): Class[_]
Returns the runtime class representation of the object.
- returns
a class object corresponding to the runtime type of the receiver.
def getOrElse(key: K, default: ⇒ V): V
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 thedefault
computation.
- Definition Classes
- MapProxyLike → MapLike → GenMapLike
def getOrElseUpdate(key: A, op: ⇒ B): B
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
, ifkey
is previously unbound.- returns
the value associated with key (either previously or as a result of executing the method).
- Definition Classes
- MapLike
def groupBy[K](f: ((A, B)) ⇒ K): immutable.Map[K, Map[A, B]]
Partitions this traversable collection into a map of traversable collections 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 traversable collection.
- K
the type of keys returned by the discriminator function.
- f
the discriminator function.
- returns
-
A map from keys to traversable collections such that the following invariant holds:
(xs groupBy f)(k) = xs filter (x => f(x) == k)
That is, every key
k
is bound to a traversable collection of those elementsx
for whichf(x)
equalsk
.
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableLike
def grouped(size: Int): Iterator[Map[A, B]]
Partitions elements in fixed size iterable collections.
- size
the number of elements per group
- returns
An iterator producing iterable collections of size
size
, except the last will be less than sizesize
if the elements don't divide evenly.
- Definition Classes
- IterableProxyLike → IterableLike
- See also
scala.collection.Iterator, method
grouped
def hasDefiniteSize: Boolean
Tests whether this traversable collection is known to have a finite size. All strict collections are known to have finite size. For a non-strict collection such as Stream
, the predicate returns true
if all elements have been computed. It returns false
if the stream is not yet evaluated to the end. Non-empty Iterators usually return false
even if they were created from a collection with a known finite size.
Note: many collection methods will not work on collections of infinite sizes. The typical failure mode is an infinite loop. These methods always attempt a traversal without checking first that hasDefiniteSize
returns true
. However, checking hasDefiniteSize
can provide an assurance that size is well-defined and non-termination is not a concern.
- returns
true
if this collection is known to have finite size,false
otherwise.
- Definition Classes
- TraversableProxyLike → TraversableLike → TraversableOnce → GenTraversableOnce
def hashCode(): Int
Calculate a hash code value for the object.
The default hashing algorithm is platform dependent.
Note that it is allowed for two objects to have identical hash codes (o1.hashCode.equals(o2.hashCode)
) yet not be equal (o1.equals(o2)
returns false
). A degenerate implementation could always return 0
. However, it is required that if two objects are equal (o1.equals(o2)
returns true
) that they have identical hash codes (o1.hashCode.equals(o2.hashCode)
). Therefore, when overriding this method, be sure to verify that the behavior is consistent with the equals
method.
- returns
the hash code value for this object.
def head: (A, B)
Selects the first element of this traversable collection.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- returns
the first element of this traversable collection.
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableLike
- Exceptions thrown
NoSuchElementException
if the traversable collection is empty.
def headOption: Option[(A, B)]
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 traversable collection if it is nonempty,
None
if it is empty.
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableLike
def init: Map[A, B]
Selects all elements except the last.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- returns
a traversable collection consisting of all elements of this traversable collection except the last one.
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableLike
- Exceptions thrown
UnsupportedOperationException
if the traversable collection is empty.
def inits: Iterator[Map[A, B]]
Iterates over the inits of this traversable collection. The first value will be this traversable collection and the final one will be an empty traversable collection, with the intervening values the results of successive applications of init
.
- returns
an iterator over all the inits of this traversable collection
- Definition Classes
- TraversableLike
List(1,2,3).inits = Iterator(List(1,2,3), List(1,2), List(1), Nil)
def isDefinedAt(key: A): Boolean
Tests whether this map contains a binding for a key. This method, which implements an abstract method of trait PartialFunction
, is equivalent to contains
.
- key
the key
- returns
true
if there is a binding forkey
in this map,false
otherwise.
- Definition Classes
- MapProxyLike → MapLike → GenMapLike → PartialFunction
def isEmpty: Boolean
Tests whether this map is empty.
- returns
true
if the map contain no elements,false
otherwise.
- Definition Classes
- MapProxyLike → TraversableProxyLike → MapLike → IterableLike → TraversableLike → TraversableOnce → GenTraversableOnce
final def isInstanceOf[T0]: Boolean
Test whether the dynamic type of the receiver object is T0
.
Note that the result of the test is modulo Scala's erasure semantics. Therefore the expression 1.isInstanceOf[String]
will return false
, while the expression List(1).isInstanceOf[List[String]]
will return true
. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the specified type.
- returns
true
if the receiver object is an instance of erasure of typeT0
;false
otherwise.
- Definition Classes
- Any
final def isTraversableAgain: Boolean
Tests whether this traversable collection can be repeatedly traversed.
- returns
true
- Definition Classes
- TraversableLike → GenTraversableLike → GenTraversableOnce
def iterator: Iterator[(A, B)]
Creates a new iterator over all elements contained in this iterable object.
- returns
the new iterator
- Definition Classes
- MapProxyLike → IterableProxyLike → MapLike → IterableLike → GenIterableLike
def keySet: collection.Set[A]
Collects all keys of this map in a set.
- returns
a set containing all keys of this map.
- Definition Classes
- MapProxyLike → MapLike → GenMapLike
def keys: collection.Iterable[A]
Collects all keys of this map in an iterable collection.
- returns
the keys of this map as an iterable.
- Definition Classes
- MapProxyLike → MapLike → GenMapLike
def keysIterator: Iterator[A]
Creates an iterator for all keys.
- returns
an iterator over all keys.
- Definition Classes
- MapProxyLike → MapLike → GenMapLike
def last: (A, B)
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 traversable collection.
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableLike
- Exceptions thrown
NoSuchElementException
If the traversable collection is empty.
def lastOption: Option[(A, B)]
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 traversable collection$ if it is nonempty,
None
if it is empty.
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableLike
def lift: (A) ⇒ Option[B]
Turns this partial function into a plain function returning an Option
result.
- returns
a function that takes an argument
x
toSome(this(x))
ifthis
is defined forx
, and toNone
otherwise.
- Definition Classes
- PartialFunction
- See also
Function.unlift
def map[B](f: (A) ⇒ B): Map[B]
Builds a new collection by applying a function to all elements of this mutable map.
- B
the element type of the returned collection.
- f
the function to apply to each element.
- returns
a new mutable map resulting from applying the given function
f
to each element of this mutable map and collecting the results.
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableLike → FilterMonadic
def mapResult[NewTo](f: (Map[A, B]) ⇒ NewTo): Builder[(A, B), NewTo]
Creates a new builder by applying a transformation function to the results of this builder.
- NewTo
the type of collection returned by
f
.- f
the transformation function.
- returns
a new builder which is the same as the current builder except that a transformation function is applied to this builder's result.
- Definition Classes
- Builder
- Note
The original builder should no longer be used after
mapResult
is called.
def mapValues[C](f: (B) ⇒ C): collection.Map[A, C]
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
- MapProxyLike → MapLike → GenMapLike
def max: A
Finds the largest element.
- returns
the largest element of this mutable map.
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
- Exceptions thrown
UnsupportedOperationException
if this mutable map is empty.
def maxBy[B](f: (A) ⇒ B): A
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 mutable map with the largest value measured by function f.
- Definition Classes
- TraversableOnce → GenTraversableOnce
- Exceptions thrown
UnsupportedOperationException
if this mutable map is empty.
def min: A
Finds the smallest element.
- returns
the smallest element of this mutable map
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
- Exceptions thrown
UnsupportedOperationException
if this mutable map is empty.
def minBy[B](f: (A) ⇒ B): A
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 mutable map with the smallest value measured by function f.
- Definition Classes
- TraversableOnce → GenTraversableOnce
- Exceptions thrown
UnsupportedOperationException
if this mutable map is empty.
def mkString: String
Displays all elements of this traversable collection in a string.
- returns
a string representation of this traversable collection. In the resulting string the string representations (w.r.t. the method
toString
) of all elements of this traversable collection follow each other without any separator string.
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
def mkString(sep: String): String
Displays all elements of this traversable collection in a string using a separator string.
- sep
the separator string.
- returns
a string representation of this traversable collection. In the resulting string the string representations (w.r.t. the method
toString
) of all elements of this traversable collection are separated by the stringsep
.
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
List(1, 2, 3).mkString("|") = "1|2|3"
def mkString(start: String, sep: String, end: String): String
Displays all elements of this traversable collection 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 traversable collection. The resulting string begins with the string
start
and ends with the stringend
. Inside, the string representations (w.r.t. the methodtoString
) of all elements of this traversable collection are separated by the stringsep
.
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"
final def ne(arg0: AnyRef): Boolean
Equivalent to !(this eq that)
.
- returns
true
if the argument is not a reference to the receiver object;false
otherwise.
- Definition Classes
- AnyRef
def newBuilder: Builder[(A, B), Map[A, B]]
A common implementation of newBuilder
for all mutable maps in terms of empty
.
Overrides MapLike
implementation for better efficiency.
- Attributes
- protected[this]
- Definition Classes
- MapLike → MapLike → TraversableLike → HasNewBuilder
def nonEmpty: Boolean
Tests whether the traversable collection is not empty.
- returns
true
if the traversable collection contains at least one element,false
otherwise.
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
final def notify(): Unit
Wakes up a single thread that is waiting on the receiver object's monitor.
- Definition Classes
- AnyRef
- Annotations
- @native()
- Note
not specified by SLS as a member of AnyRef
final def notifyAll(): Unit
Wakes up all threads that are waiting on the receiver object's monitor.
- Definition Classes
- AnyRef
- Annotations
- @native()
- Note
not specified by SLS as a member of AnyRef
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.
- 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 takesx
tothis(x)
wherethis
is defined, and tothat(x)
where it is not.
- Definition Classes
- PartialFunction
def par: ParMap[A, B]
Returns a parallel implementation of this collection.
For most collection types, this method creates a new parallel collection by copying all the elements. For these collection, par
takes linear time. Mutable collections in this category do not produce a mutable parallel collection that has the same underlying dataset, so changes in one collection will not be reflected in the other one.
Specific collections (e.g. ParArray
or mutable.ParHashMap
) override this default behaviour by creating a parallel collection which shares the same underlying dataset. For these collections, par
takes constant or sublinear time.
All parallel collections return a reference to themselves.
- returns
a parallel implementation of this collection
- Definition Classes
- Parallelizable
def parCombiner: Combiner[(A, B), ParMap[A, B]]
The default par
implementation uses the combiner provided by this method to create a new parallel collection.
- returns
a combiner for the parallel collection of type
ParRepr
- Attributes
- protected[this]
- Definition Classes
- MapLike → MapLike → TraversableLike → Parallelizable
def partition(p: ((A, B)) ⇒ Boolean): (Map[A, B], Map[A, B])
Partitions this traversable collection in two traversable collections according to a predicate.
- p
the predicate on which to partition.
- returns
a pair of traversable collections: the first traversable collection consists of all elements that satisfy the predicate
p
and the second traversable collection consists of all elements that don't. The relative order of the elements in the resulting traversable collections is the same as in the original traversable collection.
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableLike
def product: A
Multiplies up the elements of this collection.
- returns
the product of all elements in this mutable map of numbers of type
Int
. Instead ofInt
, any other typeT
with an implicitNumeric[T]
implementation can be used as element type of the mutable map and as result type ofproduct
. Examples of such types are:Long
,Float
,Double
,BigInt
.
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
def put(key: A, value: B): Option[B]
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, orNone
ifkey
was not defined in the map before.
- Definition Classes
- MapLike
def reduce[A1 >: (A, B)](op: (A1, A1) ⇒ A1): A1
Reduces the elements of this traversable or iterator using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
- A1
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 traversable or iterator is nonempty.
- Definition Classes
- TraversableOnce → GenTraversableOnce
- Exceptions thrown
UnsupportedOperationException
if this traversable or iterator is empty.
def reduceLeft[B >: (A, B)](op: (B, (A, B)) ⇒ B): B
Applies a binary operator to all elements of this traversable collection, going left to right.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.
- B
the result type of the binary operator.
- op
the binary operator.
- returns
-
the result of inserting
op
between consecutive elements of this traversable collection, going left to right:op( op( ... op(x_1, x_2) ..., x_{n-1}), x_n)
where
x1, ..., xn
are the elements of this traversable collection.
- Definition Classes
- TraversableProxyLike → TraversableOnce
- Exceptions thrown
UnsupportedOperationException
if this traversable collection is empty.
def reduceLeftOption[B >: (A, B)](op: (B, (A, B)) ⇒ B): Option[B]
Optionally applies a binary operator to all elements of this traversable collection, going left to right.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.
- B
the result type of the binary operator.
- op
the binary operator.
- returns
an option value containing the result of
reduceLeft(op)
if this traversable collection is nonempty,None
otherwise.
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
def reduceOption[A1 >: (A, B)](op: (A1, A1) ⇒ A1): Option[A1]
Reduces the elements of this traversable or iterator, if any, using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
- A1
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, andNone
otherwise.
- Definition Classes
- TraversableOnce → GenTraversableOnce
def reduceRight[B >: (A, B)](op: ((A, B), B) ⇒ B): B
Applies a binary operator to all elements of this traversable collection, going right to left.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.
- B
the result type of the binary operator.
- op
the binary operator.
- returns
-
the result of inserting
op
between consecutive elements of this traversable collection, going right to left:op(x_1, op(x_2, ..., op(x_{n-1}, x_n)...))
where
x1, ..., xn
are the elements of this traversable collection.
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
- Exceptions thrown
UnsupportedOperationException
if this traversable collection is empty.
def reduceRightOption[B >: (A, B)](op: ((A, B), B) ⇒ B): Option[B]
Optionally applies a binary operator to all elements of this traversable collection, going right to left.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.
- B
the result type of the binary operator.
- op
the binary operator.
- returns
an option value containing the result of
reduceRight(op)
if this traversable collection is nonempty,None
otherwise.
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
def remove(key: A): Option[B]
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
, orNone
ifkey
was not defined in the map before.
- Definition Classes
- MapLike
def repr: MapProxy[A, B]
The representation object of type Repr
which contains the collection's elements
- Definition Classes
- MapProxy → Subtractable → TraversableLike → GenTraversableLike
def result(): Map[A, B]
The result when this map is used as a builder
- returns
the map representation itself.
def retain(p: (A, B) ⇒ Boolean): MapProxy.this.type
Retains only those mappings for which the predicate p
returns true
.
- p
The test predicate
- Definition Classes
- MapLike
def reversed: List[(A, B)]
- Attributes
- protected[this]
- Definition Classes
- TraversableOnce
def runWith[U](action: (B) ⇒ U): (A) ⇒ Boolean
Composes this partial function with an action function which gets applied to results of this partial function. The action function is invoked only for its side effects; its result is ignored.
Note that expression pf.runWith(action)(x)
is equivalent to
if(pf isDefinedAt x) { action(pf(x)); true } else false
except that runWith
is implemented via applyOrElse
and thus potentially more efficient. Using runWith
avoids double evaluation of pattern matchers and guards for partial function literals.
- action
the action function
- returns
a function which maps arguments
x
toisDefinedAt(x)
. The resulting function runsaction(this(x))
wherethis
is defined.
- Definition Classes
- PartialFunction
- Since
2.10
- See also
applyOrElse
.
def sameElements(that: GenIterable[A]): Boolean
Checks if the other iterable collection contains the same elements in the same order as this mutable map.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- that
the collection to compare with.
- returns
true
, if both collections contain the same elements in the same order,false
otherwise.
- Definition Classes
- IterableProxyLike → IterableLike → GenIterableLike
def scan[B >: (A, B), That](z: B)(op: (B, B) ⇒ B)(implicit cbf: CanBuildFrom[Map[A, B], B, That]): That
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
- That
type of the resulting collection
- z
neutral element for the operator
op
- op
the associative operator for the scan
- cbf
combiner factory which provides a combiner
- returns
a new traversable collection containing the prefix scan of the elements in this traversable collection
- Definition Classes
- TraversableLike → GenTraversableLike
def scanLeft[B, That](z: B)(op: (B, (A, B)) ⇒ B)(implicit bf: CanBuildFrom[Map[A, B], B, That]): That
Produces a collection containing cumulative results of applying the operator going left to right.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- 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 classThat
from the current representation typeRepr
and the new element typeB
.- returns
collection with intermediate results
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableLike
def scanRight[B, That](z: B)(op: ((A, B), B) ⇒ B)(implicit bf: CanBuildFrom[Map[A, B], B, That]): That
Produces a collection containing cumulative results of applying the operator going right to left. The head of the collection is the last cumulative result.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered.
Example:
List(1, 2, 3, 4).scanRight(0)(_ + _) == List(10, 9, 7, 4, 0)
- 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 classThat
from the current representation typeRepr
and the new element typeB
.- returns
collection with intermediate results
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableLike
def seq: Map[A, B]
A version of this collection with all of the operations implemented sequentially (i.e., in a single-threaded manner).
This method returns a reference to this collection. In parallel collections, it is redefined to return a sequential implementation of this collection. In both cases, it has O(1) complexity.
- returns
a sequential view of the collection.
- Definition Classes
- Map → Map → GenMap → GenMapLike → Iterable → Iterable → GenIterable → Traversable → Traversable → GenTraversable → Parallelizable → TraversableOnce → GenTraversableOnce
def size: Int
The size of this traversable collection.
Note: will not terminate for infinite-sized collections.
- returns
the number of elements in this traversable collection.
- Definition Classes
- TraversableProxyLike → GenTraversableLike → TraversableOnce → GenTraversableOnce
def sizeHint(coll: TraversableLike[_, _], delta: Int): Unit
Gives a hint that one expects the result
of this builder to have the same size as the given collection, plus some delta. This will provide a hint only if the collection is known to have a cheap size
method. Currently this is assumed to be the case if and only if the collection is of type IndexedSeqLike
. Some builder classes will optimize their representation based on the hint. However, builder implementations are still required to work correctly even if the hint is wrong, i.e. a different number of elements is added.
- coll
the collection which serves as a hint for the result's size.
- delta
a correction to add to the
coll.size
to produce the size hint.
- Definition Classes
- Builder
def sizeHint(coll: TraversableLike[_, _]): Unit
Gives a hint that one expects the result
of this builder to have the same size as the given collection, plus some delta. This will provide a hint only if the collection is known to have a cheap size
method, which is determined by calling sizeHint
.
Some builder classes will optimize their representation based on the hint. However, builder implementations are still required to work correctly even if the hint is wrong, i.e. a different number of elements is added.
- coll
the collection which serves as a hint for the result's size.
- Definition Classes
- Builder
def sizeHint(size: Int): Unit
Gives a hint how many elements are expected to be added when the next result
is called. Some builder classes will optimize their representation based on the hint. However, builder implementations are still required to work correctly even if the hint is wrong, i.e. a different number of elements is added.
- size
the hint how many elements will be added.
- Definition Classes
- Builder
def sizeHintBounded(size: Int, boundingColl: TraversableLike[_, _]): Unit
Gives a hint how many elements are expected to be added when the next result
is called, together with an upper bound given by the size of some other collection. Some builder classes will optimize their representation based on the hint. However, builder implementations are still required to work correctly even if the hint is wrong, i.e. a different number of elements is added.
- size
the hint how many elements will be added.
- boundingColl
the bounding collection. If it is an IndexedSeqLike, then sizes larger than collection's size are reduced.
- Definition Classes
- Builder
def sizeHintIfCheap: Int
The size of this collection or iterator, if it can be cheaply computed
- returns
the number of elements in this collection or iterator, or -1 if the size cannot be determined cheaply
- Attributes
- protected[collection]
- Definition Classes
- GenTraversableOnce
def slice(from: Int, until: Int): Map[A, B]
Selects an interval of elements. The returned collection is made up of all elements x
which satisfy the invariant:
from <= indexOf(x) < until
Note: might return different results for different runs, unless the underlying collection type is ordered.
- returns
a traversable collection containing the elements greater than or equal to index
from
extending up to (but not including) indexuntil
of this traversable collection.
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableLike
def sliding(size: Int, step: 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.)
- size
the number of elements per group
- step
the distance between the first elements of successive groups
- returns
An iterator producing iterable collections of size
size
, except the last element (which may be the only element) will be truncated if there are fewer thansize
elements remaining to be grouped.
- Definition Classes
- IterableProxyLike → IterableLike
- See also
scala.collection.Iterator, method
sliding
def sliding(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
.) The "sliding window" step is set to one.
- size
the number of elements per group
- returns
An iterator producing iterable collections of size
size
, except the last element (which may be the only element) will be truncated if there are fewer thansize
elements remaining to be grouped.
- Definition Classes
- IterableProxyLike → IterableLike
- See also
scala.collection.Iterator, method
sliding
def span(p: ((A, B)) ⇒ Boolean): (Map[A, B], Map[A, B])
Splits this traversable collection into a prefix/suffix pair according to a predicate.
Note: c span p
is equivalent to (but possibly more efficient than) (c takeWhile p, c dropWhile p)
, provided the evaluation of the predicate p
does not cause any side-effects.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- returns
a pair consisting of the longest prefix of this traversable collection whose elements all satisfy
p
, and the rest of this traversable collection.
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableLike
def splitAt(n: Int): (Map[A, B], Map[A, B])
Splits this traversable collection 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 traversable collections consisting of the first
n
elements of this traversable collection, and the other elements.
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableLike
def stringPrefix: String
Defines the prefix of this object's toString
representation.
- returns
a string representation which starts the result of
toString
applied to this traversable collection. By default the string prefix is the simple name of the collection class traversable collection.
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableLike
def sum: A
Sums up the elements of this collection.
- returns
the sum of all elements in this mutable map of numbers of type
Int
. Instead ofInt
, any other typeT
with an implicitNumeric[T]
implementation can be used as element type of the mutable map and as result type ofsum
. Examples of such types are:Long
,Float
,Double
,BigInt
.
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
final def synchronized[T0](arg0: ⇒ T0): T0
- Definition Classes
- AnyRef
def tail: Map[A, B]
Selects all elements except the first.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- returns
a traversable collection consisting of all elements of this traversable collection except the first one.
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableLike
- Exceptions thrown
java.lang.UnsupportedOperationException
if the traversable collection is empty.
def tails: Iterator[Map[A, B]]
Iterates over the tails of this traversable collection. The first value will be this traversable collection and the final one will be an empty traversable collection, with the intervening values the results of successive applications of tail
.
- returns
an iterator over all the tails of this traversable collection
- Definition Classes
- TraversableLike
List(1,2,3).tails = Iterator(List(1,2,3), List(2,3), List(3), Nil)
def take(n: Int): Map[A, B]
Selects first n elements.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- n
the number of elements to take from this traversable collection.
- returns
a traversable collection consisting only of the first
n
elements of this traversable collection, or else the whole traversable collection, if it has less thann
elements. Ifn
is negative, returns an empty traversable collection.
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableLike
def takeRight(n: Int): Map[A, B]
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 iterable collection consisting only of the last
n
elements of this iterable collection, or else the whole iterable collection, if it has less thann
elements.
- Definition Classes
- IterableProxyLike → IterableLike
def takeWhile(p: ((A, B)) ⇒ Boolean): Map[A, B]
Takes longest prefix of elements that satisfy a predicate.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- returns
the longest prefix of this traversable collection whose elements all satisfy the predicate
p
.
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableLike
def thisCollection: collection.Iterable[(A, B)]
The underlying collection seen as an instance of Iterable
. By default this is implemented as the current collection object itself, but this can be overridden.
- Attributes
- protected[this]
- Definition Classes
- IterableLike → TraversableLike
def to[Col[_]]: Col[A]
Converts this mutable map into another by copying all elements.
- Col
The collection type to build.
- returns
a new collection containing all elements of this mutable map.
- Definition Classes
- TraversableLike → TraversableOnce → GenTraversableOnce
def toArray: Array[A]
Converts this mutable map to an array.
- returns
an array containing all elements of this mutable map. An
ClassTag
must be available for the element type of this mutable map.
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
def toBuffer[B >: (A, B)]: Buffer[B]
Uses the contents of this traversable collection to create a new mutable buffer.
Note: will not terminate for infinite-sized collections.
- returns
a buffer containing all elements of this traversable collection.
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
def toCollection(repr: Map[A, B]): collection.Iterable[(A, B)]
A conversion from collections of type Repr
to Iterable
objects. By default this is implemented as just a cast, but this can be overridden.
- Attributes
- protected[this]
- Definition Classes
- IterableLike → TraversableLike
def toIndexedSeq: immutable.IndexedSeq[(A, B)]
Converts this traversable collection to an indexed sequence.
Note: will not terminate for infinite-sized collections.
- returns
an indexed sequence containing all elements of this traversable collection.
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
def toIterable: collection.Iterable[(A, B)]
Converts this traversable collection 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).
Note: will not terminate for infinite-sized collections.
- returns
an
Iterable
containing all elements of this traversable collection.
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
def toIterator: Iterator[(A, B)]
Returns an Iterator over the elements in this traversable collection. Will return the same Iterator if this instance is already an Iterator.
Note: will not terminate for infinite-sized collections.
- returns
an Iterator containing all elements of this traversable collection.
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableOnce
def toList: List[(A, B)]
Converts this traversable collection to a list.
Note: will not terminate for infinite-sized collections.
- returns
a list containing all elements of this traversable collection.
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
def toMap[T, U]: collection.Map[T, U]
Converts this mutable map to a map. This method is unavailable unless the elements are members of Tuple2, each ((T, U)) 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 of type
immutable.Map[T, U]
containing all key/value pairs of type(T, U)
of this mutable map.
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
def toParArray: ParArray[T]
- Implicit
- This member is added by an implicit conversion from MapProxy[A, B] to CollectionsHaveToParArray[MapProxy[A, B], T] performed by method CollectionsHaveToParArray in scala.collection.parallel. This conversion will take place only if an implicit value of type (MapProxy[A, B]) ⇒ GenTraversableOnce[T] is in scope.
- Definition Classes
- CollectionsHaveToParArray
def toSeq: collection.Seq[(A, B)]
Converts this traversable collection to a sequence. As with toIterable
, it's lazy in this default implementation, as this TraversableOnce
may be lazy and unevaluated.
Note: will not terminate for infinite-sized collections.
- returns
a sequence containing all elements of this traversable collection.
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
def toSet[B >: (A, B)]: immutable.Set[B]
Converts this traversable collection to a set.
Note: will not terminate for infinite-sized collections.
- returns
a set containing all elements of this traversable collection.
- Definition Classes
- TraversableProxyLike → TraversableOnce → GenTraversableOnce
def toStream: Stream[(A, B)]
Converts this traversable collection to a stream.
- returns
a stream containing all elements of this traversable collection.
- Definition Classes
- TraversableProxyLike → TraversableLike → GenTraversableOnce
def toString(): String
Returns a string representation of the object.
The default representation is platform dependent.
- returns
a string representation of the object.
def toTraversable: collection.Traversable[(A, B)]
Converts this traversable collection to an unspecified Traversable. Will return the same collection if this instance is already Traversable.
Note: will not terminate for infinite-sized collections.
- returns
a Traversable containing all elements of this traversable collection.
- Definition Classes
- TraversableProxyLike → TraversableLike → TraversableOnce → GenTraversableOnce
def toVector: Vector[(A, B)]
Converts this traversable or iterator to a Vector.
Note: will not terminate for infinite-sized collections.
- returns
a vector containing all elements of this traversable or iterator.
- Definition Classes
- TraversableOnce → GenTraversableOnce
def transform(f: (A, B) ⇒ B): MapProxy.this.type
Applies a transformation function to all values contained in this map. The transformation function produces new values from existing keys associated values.
- f
the transformation to apply
- returns
the map itself.
- Definition Classes
- MapLike
def transpose[B](implicit asTraversable: ((A, B)) ⇒ GenTraversableOnce[B]): Iterable[Iterable[B]]
Transposes this collection of traversable collections into a collection of collections.
The resulting collection's type will be guided by the static type of collection. For example:
val xs = List( Set(1, 2, 3), Set(4, 5, 6)).transpose // xs == List( // List(1, 4), // List(2, 5), // List(3, 6)) val ys = Vector( List(1, 2, 3), List(4, 5, 6)).transpose // ys == Vector( // Vector(1, 4), // Vector(2, 5), // Vector(3, 6))
- B
the type of the elements of each traversable collection.
- asTraversable
an implicit conversion which asserts that the element type of this collection is a
Traversable
.- returns
a two-dimensional collection of collections which has as nth row the nth column of this collection.
- Definition Classes
- GenericTraversableTemplate
- Annotations
- @migration
- Migration
(Changed in version 2.9.0)
transpose
throws anIllegalArgumentException
if collections are not uniformly sized.- Exceptions thrown
IllegalArgumentException
if all collections in this collection are not of the same size.
def unzip[A1, A2](implicit asPair: ((A, B)) ⇒ (A1, A2)): (Iterable[A1], Iterable[A2])
Converts this collection of pairs into two collections of the first and second half of each pair.
val xs = Traversable( (1, "one"), (2, "two"), (3, "three")).unzip // xs == (Traversable(1, 2, 3), // Traversable(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 collection is a pair.
- returns
a pair of collections, containing the first, respectively second half of each element pair of this collection.
- Definition Classes
- GenericTraversableTemplate
def unzip3[A1, A2, A3](implicit asTriple: ((A, B)) ⇒ (A1, A2, A3)): (Iterable[A1], Iterable[A2], Iterable[A3])
Converts this collection of triples into three collections of the first, second, and third element of each triple.
val xs = Traversable( (1, "one", '1'), (2, "two", '2'), (3, "three", '3')).unzip3 // xs == (Traversable(1, 2, 3), // Traversable(one, two, three), // Traversable(1, 2, 3))
- A1
the type of the first member of the element triples
- A2
the type of the second member of the element triples
- A3
the type of the third member of the element triples
- asTriple
an implicit conversion which asserts that the element type of this collection is a triple.
- returns
a triple of collections, containing the first, second, respectively third member of each element triple of this collection.
- Definition Classes
- GenericTraversableTemplate
def update(key: A, value: B): Unit
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
- MapLike
def updated[B1 >: B](key: A, value: B1): MapProxy[A, B1]
Creates a new map obtained by updating this map with a given key/value pair.
- key
the key
- value
the value
- returns
A new map with the new key/value mapping added to this map.
- Definition Classes
- MapProxy → MapProxyLike → MapLike → MapLike → GenMap
def values: collection.Iterable[B]
Collects all values of this map in an iterable collection.
- returns
the values of this map as an iterable.
- Definition Classes
- MapProxyLike → MapLike → GenMapLike
def valuesIterator: Iterator[B]
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
- MapProxyLike → MapLike → GenMapLike
def view(from: Int, until: Int): IterableView[(A, B), Map[A, B]]
Creates a non-strict view of a slice of this iterable collection.
Note: the difference between view
and slice
is that view
produces a view of the current iterable collection, whereas slice
produces a new iterable collection.
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 iterable collection, starting at index
from
and extending up to (but not including) indexuntil
.
- Definition Classes
- IterableProxyLike → TraversableProxyLike → IterableLike → TraversableLike
def view: IterableView[(A, B), Map[A, B]]
Creates a non-strict view of this iterable collection.
- returns
a non-strict view of this iterable collection.
- Definition Classes
- IterableProxyLike → TraversableProxyLike → IterableLike → TraversableLike
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
def withDefault(d: (A) ⇒ B): Map[A, B]
The same map with a given default function.
Invoking transformer methods (e.g. map
) will not preserve the default value.
- d
the function mapping keys to values, used for non-present keys
- returns
a wrapper of the map with a default value
- Definition Classes
- Map
def withDefaultValue(d: B): Map[A, B]
The same map with a given default value.
Invoking transformer methods (e.g. map
) will not preserve the default value.
- d
default value used for non-present keys
- returns
a wrapper of the map with a default value
- Definition Classes
- Map
def withFilter(p: ((A, B)) ⇒ Boolean): FilterMonadic[(A, B), Map[A, B]]
Creates a non-strict filter of this traversable collection.
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 supportsmap
,flatMap
,foreach
, andwithFilter
operations. All these operations apply to those elements of this traversable collection which satisfy the predicatep
.
- Definition Classes
- TraversableLike → FilterMonadic
def zip[B](that: GenIterable[B]): Map[(A, B)]
Returns a mutable map formed from this mutable 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.
- 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 mutable map containing pairs consisting of corresponding elements of this mutable map and
that
. The length of the returned collection is the minimum of the lengths of this mutable map andthat
.
- Definition Classes
- IterableProxyLike → IterableLike → GenIterableLike
def zipAll[B](that: collection.Iterable[B], thisElem: A, thatElem: B): Map[(A, B)]
Returns a mutable map formed from this mutable 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.
- 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 mutable map is shorter than
that
.- thatElem
the element to be used to fill up the result if
that
is shorter than this mutable map.- returns
a new mutable map containing pairs consisting of corresponding elements of this mutable map and
that
. The length of the returned collection is the maximum of the lengths of this mutable map andthat
. If this mutable map is shorter thanthat
,thisElem
values are used to pad the result. Ifthat
is shorter than this mutable map,thatElem
values are used to pad the result.
- Definition Classes
- IterableProxyLike → IterableLike → GenIterableLike
def zipWithIndex: Map[(A, Int)]
Zips this mutable map with its indices.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- returns
A new mutable map containing pairs consisting of all elements of this mutable map paired with their index. Indices start at
0
.
- Definition Classes
- IterableProxyLike → IterableLike → GenIterableLike
List("a", "b", "c").zipWithIndex = List(("a", 0), ("b", 1), ("c", 2))
def →[B](y: B): (MapProxy[A, B], B)
- Implicit
- This member is added by an implicit conversion from MapProxy[A, B] to ArrowAssoc[MapProxy[A, B]] performed by method ArrowAssoc in scala.Predef.
- Definition Classes
- ArrowAssoc
Shadowed Implicit Value Members
def +(other: String): String
- Implicit
- This member is added by an implicit conversion from MapProxy[A, B] to any2stringadd[MapProxy[A, B]] performed by method any2stringadd in scala.Predef.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(mapProxy: any2stringadd[MapProxy[A, B]]).+(other)
- Definition Classes
- any2stringadd
def filter(p: ((A, B)) ⇒ Boolean): TraversableOnce[(A, B)]
- Implicit
- This member is added by an implicit conversion from MapProxy[A, B] to MonadOps[(A, B)] performed by method MonadOps in scala.collection.TraversableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(mapProxy: MonadOps[(A, B)]).filter(p)
- Definition Classes
- MonadOps
def flatMap[B](f: ((A, B)) ⇒ GenTraversableOnce[B]): TraversableOnce[B]
- Implicit
- This member is added by an implicit conversion from MapProxy[A, B] to MonadOps[(A, B)] performed by method MonadOps in scala.collection.TraversableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(mapProxy: MonadOps[(A, B)]).flatMap(f)
- Definition Classes
- MonadOps
def map[B](f: ((A, B)) ⇒ B): TraversableOnce[B]
- Implicit
- This member is added by an implicit conversion from MapProxy[A, B] to MonadOps[(A, B)] performed by method MonadOps in scala.collection.TraversableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(mapProxy: MonadOps[(A, B)]).map(f)
- Definition Classes
- MonadOps
def withFilter(p: ((A, B)) ⇒ Boolean): Iterator[(A, B)]
- Implicit
- This member is added by an implicit conversion from MapProxy[A, B] to MonadOps[(A, B)] performed by method MonadOps in scala.collection.TraversableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(mapProxy: MonadOps[(A, B)]).withFilter(p)
- Definition Classes
- MonadOps
© 2002-2019 EPFL, with contributions from Lightbend.
Licensed under the Apache License, Version 2.0.
https://www.scala-lang.org/api/2.12.9/scala/collection/mutable/MapProxy.html
This trait implements a proxy for scala.collection.mutable.Map.
It is most useful for assembling customized map abstractions dynamically using object composition and forwarding.
(Since version 2.11.0) proxying is deprecated due to lack of use and compiler-level support
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