The implementation class of the set returned by keySet.
The implementation class of the iterable returned by values.
The type implementing this traversable
The type implementing this traversable
A class supporting filtered operations.
Test two objects for inequality.
Test two objects for inequality.
true if !(this == that), false otherwise.
Equivalent to x.hashCode except for boxed numeric types.
Equivalent to x.hashCode except for boxed numeric types.
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.
a hash value consistent with ==
[use case] Adds key/value pairs to this map, returning a new map.
Adds key/value pairs to this map, returning a new map.
the remaining key/value pairs
a new map with the given bindings added to this map
Adds key/value pairs to this map, returning a new map.
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.
the type of the added values
the first key/value pair
the second key/value pair
the remaining key/value pairs
a new map with the given bindings added to this map
[use case] Adds a key/value pair to this map, returning a new map.
Adds a key/value pair to this map, returning a new map.
the key/value pair
a new map with the new binding added to this map
Adds a key/value pair to this map, returning a new map.
Adds a key/value pair to this map, returning a new map.
the type of the value in the key/value pair.
the key/value pair
a new map with the new binding added to this map
[use case] Adds all key/value pairs in a traversable collection to this map, returning a new map.
Adds all key/value pairs in a traversable collection to this map, returning a new map.
a new map with the given bindings added to this map
Adds all key/value pairs in a traversable collection to this map, returning a new map.
Adds all key/value pairs in a traversable collection to this map, returning a new map.
the type of the added values
a new map with the given bindings added to this map
[use case] Returns a new map containing the elements from the left hand operand followed by the elements from the right hand operand.
Returns a new map containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the map is the most specific superclass encompassing the element types of the two operands (see example).
the element type of the returned collection.
the traversable to append.
a new collection of type That which contains all elements
of this map followed by all elements of that.
Returns a new map containing the elements from the left hand operand followed by the elements from the right hand operand.
Returns a new map containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the map is the most specific superclass encompassing the element types of the two operands (see example).
Example:
scala> val a = LinkedList(1)
a: scala.collection.mutable.LinkedList[Int] = LinkedList(1)
scala> val b = LinkedList(2)
b: scala.collection.mutable.LinkedList[Int] = LinkedList(2)
scala> val c = a ++ b
c: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2)
scala> val d = LinkedList('a')
d: scala.collection.mutable.LinkedList[Char] = LinkedList(a)
scala> val e = c ++ d
e: scala.collection.mutable.LinkedList[AnyVal] = LinkedList(1, 2, a)
the element type of the returned collection.
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.
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.
a new collection of type That which contains all elements
of this map followed by all elements of that.
As with ++, returns a new collection containing the elements from the left operand followed by the
elements from the right operand.
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.
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.
the element type of the returned collection.
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.
the traversable to append.
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.
a new map which contains all elements of this map
followed by all elements of that.
[use case] Concatenates this map with the elements of a traversable collection.
Concatenates this map with the elements of a traversable collection. It differs from ++ in that the right operand determines the type of the resulting collection rather than the left one.
the element type of the returned collection.
the traversable to append.
a new collection of type That which contains all elements
of this map followed by all elements of that.
Concatenates this map with the elements of a traversable collection.
Concatenates this map with the elements of a traversable collection. It differs from ++ in that the right operand determines the type of the resulting collection rather than the left one.
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)
the element type of the returned collection.
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.
the traversable to append.
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.
a new collection of type That which contains all elements
of this map followed by all elements of that.
[use case] Removes a key from this map, returning a new map.
Removes a key from this map, returning a new map.
the key to be removed
a new map without a binding for key
Removes a key from this map, returning a new map.
Removes a key from this map, returning a new map.
the key to be removed
a new map without a binding for key
Creates a new map from this map with some elements removed.
Creates a new map from this 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.
the first element to remove.
the second element to remove.
the remaining elements to remove.
a new map that contains all elements of the current map except one less occurrence of each of the given elements.
Creates a new map from this map by removing all elements of another collection.
Creates a new map from this map by removing all elements of another collection.
a new map that contains all elements of the current map
except one less occurrence of each of the elements of elems.
Applies a binary operator to a start value and all elements of this map, going left to right.
Applies a binary operator to a start value and all elements of this map, 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 = LinkedList(1,2,3,4)
a: scala.collection.mutable.LinkedList[Int] = LinkedList(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: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.
the result type of the binary operator.
the start value.
the binary operator.
the result of inserting op between consecutive elements of this map,
going left to right with the start value z on the left:
op(...op(op(z, x1), x2), ..., xn)
where x1, ..., xn are the elements of this map.
A syntactic sugar for out of order folding.
A syntactic sugar for out of order folding. See fold.
Example:
scala> val a = LinkedList(1,2,3,4)
a: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2, 3, 4)
scala> val b = (a /:\ 5)(_+_)
b: Int = 15
Applies a binary operator to all elements of this map and a start value, going right to left.
Applies a binary operator to all elements of this 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.
Examples:
Note that the folding function used to compute b is equivalent to that used to compute c.
scala> val a = LinkedList(1,2,3,4)
a: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2, 3, 4)
scala> val b = (a :\ 5)(_+_)
b: Int = 15
scala> val c = (a :\ 5)((x,y) => x + y)
c: Int = 15
the result type of the binary operator.
the start value
the binary operator
the result of inserting op between consecutive elements of this map,
going right to left with the start value z on the right:
op(x1, op(x2, ... op(xn, z)...))
where x1, ..., xn are the elements of this map.
Test two objects for equality.
Test two objects for equality.
true if the receiver object is equivalent to the argument; false otherwise.
Appends all elements of this map to a string builder using start, end, and separator strings.
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 = LinkedList(1,2,3,4)
a: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2, 3, 4)
scala> val b = new StringBuilder()
b: StringBuilder =
scala> a.addString(b, "LinkedList(", ", ", ")")
res1: StringBuilder = LinkedList(1, 2, 3, 4)
the string builder to which elements are appended.
the starting string.
the separator string.
the ending string.
the string builder b to which elements were appended.
Appends all elements of this map to a string builder.
Appends all elements of this map to a string builder.
The written text consists of the string representations (w.r.t. the method
toString) of all elements of this map without any separator string.
Example:
scala> val a = LinkedList(1,2,3,4)
a: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2, 3, 4)
scala> val b = new StringBuilder()
b: StringBuilder =
scala> val h = a.addString(b)
b: StringBuilder = 1234
the string builder to which elements are appended.
the string builder b to which elements were appended.
Appends all elements of this map to a string builder using a separator string.
Appends all elements of this 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 map, separated by the
string sep.
Example:
scala> val a = LinkedList(1,2,3,4)
a: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2, 3, 4)
scala> val b = new StringBuilder()
b: StringBuilder =
scala> a.addString(b, ", ")
res0: StringBuilder = 1, 2, 3, 4
the string builder to which elements are appended.
the separator string.
the string builder b to which elements were appended.
Aggregates the results of applying an operator to subsequent elements.
Aggregates the results of applying an operator to subsequent elements.
This is a more general form of fold and reduce. It has similar
semantics, but does not require the result to be a supertype of the
element type. It traverses the elements in different partitions
sequentially, using seqop to update the result, and then applies
combop to results from different partitions. The implementation of
this operation may operate on an arbitrary number of collection
partitions, so combop may be invoked an arbitrary number of times.
For example, one might want to process some elements and then produce
a Set. In this case, seqop would process an element and append it
to the list, while combop would concatenate two lists from different
partitions together. The initial value z would be an empty set.
pc.aggregate(Set[Int]())(_ += process(_), _ ++ _)
Another example is calculating geometric mean from a collection of doubles (one would typically require big doubles for this).
the type of accumulated results
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 or 0 for summation)
an operator used to accumulate results within a partition
an associative operator used to combine results from different partitions
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.
the result type of the transformation function.
the transformation function
a partial function with the same domain as this partial function, which maps
arguments x to k(this(x)).
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.
the key
the value associated with the given key, or the result of the
map's default method, if none exists.
Cast the receiver object to be of type 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.
the receiver object.
if the receiver object is not an instance of the erasure of type T0.
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.
The object with which this map should be compared
true, if this map can possibly equal that, false otherwise. The test
takes into consideration only the run-time types of objects but ignores their elements.
Create a copy of the receiver object.
[use case] Builds a new collection by applying a partial function to all elements of this map on which the function is defined.
Builds a new collection by applying a partial function to all elements of this map on which the function is defined.
the element type of the returned collection.
the partial function which filters and maps the map.
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.
Builds a new collection by applying a partial function to all elements of this map on which the function is defined.
Builds a new collection by applying a partial function to all elements of this map on which the function is defined.
the element type of the returned collection.
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.
the partial function which filters and maps the map.
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.
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.
Finds the first element of the map for which the given partial function is defined, and applies the partial function to it.
Finds the first element of the map for which the given partial function is defined, and applies the partial function to it.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the partial function
an option value containing pf applied to the first
value for which it is defined, or None if none exists.
Seq("a", 1, 5L).collectFirst({ case x: Int => x*10 }) = Some(10)
The factory companion object that builds instances of class Map.
The factory companion object that builds instances of class Map.
(or its Iterable superclass where class Map is not a Seq.)
Composes two instances of Function1 in a new Function1, with this function applied last.
Composes two instances of Function1 in a new Function1, with this function applied last.
the type to which function g can be applied
a function A => T1
a new function f such that f(x) == apply(g(x))
Tests whether this map contains a binding for a key.
Tests whether this map contains a binding for a key.
the key
true if there is a binding for key in this map, false otherwise.
[use case] Copies values of this map to an array.
Copies values of this map to an array.
Fills the given array xs with values of this map.
Copying will stop once either the end of the current map is reached,
or the end of the array is reached.
the array to fill.
Copies values of this map to an array.
Copies values of this map to an array.
Fills the given array xs with values of this map.
Copying will stop once either the end of the current map is reached,
or the end of the array is reached.
the type of the elements of the array.
the array to fill.
[use case] Copies values of this map to an array.
Copies values of this map to an array.
Fills the given array xs with values of this map, beginning at index start.
Copying will stop once either the end of the current map is reached,
or the end of the array is reached.
the array to fill.
the starting index.
Copies values of this map to an array.
Copies values of this map to an array.
Fills the given array xs with values of this map, beginning at index start.
Copying will stop once either the end of the current map is reached,
or the end of the array is reached.
the type of the elements of the array.
the array to fill.
the starting index.
[use case] Copies elements of this map to an array.
Copies elements of this map to an array.
Fills the given array xs with at most len elements of
this map, starting at position start.
Copying will stop once either the end of the current map is reached,
or the end of the array is reached, or len elements have been copied.
the array to fill.
the starting index.
the maximal number of elements to copy.
Copies elements of this map to an array.
Copies elements of this map to an array.
Fills the given array xs with at most len elements of
this map, starting at position start.
Copying will stop once either the end of the current map is reached,
or the end of the array is reached, or len elements have been copied.
the type of the elements of the array.
the array to fill.
the starting index.
the maximal number of elements to copy.
Copies all elements of this map to a buffer.
Copies all elements of this map to a buffer.
The buffer to which elements are copied.
Counts the number of elements in the map which satisfy a predicate.
Counts the number of elements in the map which satisfy a predicate.
the predicate used to test elements.
the number of elements satisfying the predicate p.
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.
the given key value for which a binding is missing.
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.
the number of elements to drop from this map.
a map consisting of all elements of this map except the first n ones, or else the
empty map, if this map has less than n elements.
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.
The number of elements to take
a map consisting of all elements of this map except the last n ones, or else the
empty map, if this map has less than n elements.
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.
The predicate used to test elements.
the longest suffix of this map whose first element
does not satisfy the predicate p.
The empty map of the same type as this map
Tests whether the argument (arg0) is a reference to the receiver object (this).
Tests whether the argument (arg0) 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:
x and y of type AnyRef, multiple invocations of
x.eq(y) consistently returns true or consistently returns false.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).
true if the argument is a reference to the receiver object; false otherwise.
The equality method for reference types.
Tests whether a predicate holds for some of the elements of this map.
Tests whether a predicate holds for some of the elements of this map.
the predicate used to test elements.
true if the given predicate p holds for some of the
elements of this map, otherwise false.
Selects all elements of this map which satisfy a predicate.
Selects all elements of this map which satisfy a predicate.
the predicate used to test elements.
a new map consisting of all elements of this map that satisfy the given
predicate p. The order of the elements is preserved.
Filters this map by retaining only keys satisfying a predicate.
Filters this map by retaining only keys satisfying a predicate.
the predicate used to test keys
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.
Selects all elements of this map which do not satisfy a predicate.
Selects all elements of this map which do not satisfy a predicate.
the predicate used to test elements.
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.
Called by the garbage collector on the receiver object when there are no more references to the object.
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.
Finds the first element of the map satisfying a predicate, if any.
Finds the first element of the map satisfying a predicate, if any.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the predicate used to test elements.
an option value containing the first element in the map
that satisfies p, or None if none exists.
[use case] Builds a new collection by applying a function to all elements of this map and using the elements of the resulting collections.
Builds a new collection by applying a function to all elements of this map and using the elements of the resulting collections. For example:
the element type of the returned collection.
the function to apply to each element.
a new collection of type That resulting from applying the given collection-valued function
f to each element of this map and concatenating the results.
Builds a new collection by applying a function to all elements of this map and using the elements of the resulting collections.
Builds a new collection by applying a function to all elements of this 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 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 a 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)
the element type of the returned collection.
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.
the function to apply to each element.
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.
a new collection of type That resulting from applying the given collection-valued function
f to each element of this map and concatenating the results.
[use case] Converts this map of traversable collections into a map formed by the elements of these traversable collections.
Converts this map of traversable collections into a map formed by the elements of these traversable collections.
the type of the elements of each traversable collection.
a new map resulting from concatenating all element maps.
Folds the elements of this map using the specified associative binary operator.
Folds the elements of this map using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
a type parameter for the binary operator, a supertype of A.
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.)
a binary operator that must be associative
the result of applying fold operator op between all the elements and z
Applies a binary operator to a start value and all elements of this map, going left to right.
Applies a binary operator to a start value and all elements of this 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.
the result type of the binary operator.
the start value.
the binary operator.
the result of inserting op between consecutive elements of this map,
going left to right with the start value z on the left:
op(...op(z, x1), x2, ..., xn)
where x1, ..., xn are the elements of this map.
Applies a binary operator to all elements of this map and a start value, going right to left.
Applies a binary operator to all elements of this 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.
the result type of the binary operator.
the start value.
the binary operator.
the result of inserting op between consecutive elements of this map,
going right to left with the start value z on the right:
op(x1, op(x2, ... op(xn, z)...))
where x1, ..., xn are the elements of this map.
Tests whether a predicate holds for all elements of this map.
Tests whether a predicate holds for all elements of this map.
the predicate used to test elements.
true if the given predicate p holds for all elements
of this map, otherwise false.
[use case] Applies a function f to all elements of this map.
Applies a function f to all elements of this map.
the function that is applied for its side-effect to every element.
The result of function f is discarded.
Applies a function f to all elements of this map.
Applies a function f to all elements of this map.
Note: this method underlies the implementation of most other bulk operations. It's important to implement this method in an efficient way.
the function that is applied for its side-effect to every element.
The result of function f is discarded.
The generic builder that builds instances of Map at arbitrary element types.
The generic builder that builds instances of Map at arbitrary element types.
Optionally returns the value associated with a key.
Optionally returns the value associated with a key.
the key value
an option value containing the value associated with key in this map,
or None if none exists.
A representation that corresponds to the dynamic class of the receiver object.
A representation that corresponds to the dynamic class of the receiver object.
The nature of the representation is platform dependent.
a representation that corresponds to the dynamic class of the receiver object.
not specified by SLS as a member of AnyRef
[use case] 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.
the key.
a computation that yields a default value in case no binding for key is
found in the map.
the value associated with key if it exists,
otherwise the result of the default computation.
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.
the result type of the default computation.
the key.
a computation that yields a default value in case no binding for key is
found in the map.
the value associated with key if it exists,
otherwise the result of the default computation.
Partitions this map into a map of maps according to some discriminator function.
Partitions this map into a map of 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 map.
the type of keys returned by the discriminator function.
the discriminator function.
A map from keys to 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 map of those elements x
for which f(x) equals k.
Partitions elements in fixed size maps.
Partitions elements in fixed size maps.
the number of elements per group
An iterator producing maps of size size, except the
last will be truncated if the elements don't divide evenly.
Iterator#grouped
Tests whether this map is known to have a finite size.
Tests whether this 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.
true if this collection is known to have finite size, false otherwise.
The hashCode method for reference types.
Selects the first element of this map.
Selects the first element of this map.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the first element of this map.
if the map is empty.
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.
the first element of this map if it is nonempty, None if it is empty.
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.
a map consisting of all elements of this map except the last one.
if the map is empty.
Iterates over the inits of this map.
Iterates over the inits of this map. The first value will be this
map and the final one will be an empty map, with the intervening
values the results of successive applications of init.
an iterator over all the inits of this map
List(1,2,3).inits = Iterator(List(1,2,3), List(1,2), List(1), Nil)
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.
the key
true if there is a binding for key in this map, false otherwise.
Tests whether this map is empty.
Tests whether this map is empty.
true if the map contain no elements, false otherwise.
Test whether the dynamic type of the receiver object is T0.
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.
true if the receiver object is an instance of erasure of type T0; false otherwise.
Tests whether this map can be repeatedly traversed.
Tests whether this map can be repeatedly traversed.
true
Creates a new iterator over all elements contained in this iterable object.
Creates a new iterator over all elements contained in this iterable object.
the new iterator
Collects all keys of this map in a set.
Collects all keys of this map in a set.
a set containing all keys of this map.
Collects all keys of this map in an iterable collection.
Collects all keys of this map in an iterable collection.
the keys of this map as an iterable.
Creates an iterator for all keys.
Creates an iterator for all keys.
an iterator over all keys.
Selects the last element.
Selects the last element.
Note: might return different results for different runs, unless the underlying collection type is ordered.
The last element of this map.
If the map is empty.
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.
the last element of this map$ if it is nonempty, None if it is empty.
Turns this partial function into an plain function returning an Option result.
Turns this partial function into an plain function returning an Option result.
a function that takes an argument x to Some(this(x)) if this
is defined for x, and to None otherwise.
Function.unlift
[use case] Builds a new collection by applying a function to all elements of this map.
Builds a new collection by applying a function to all elements of this map.
the element type of the returned collection.
the function to apply to each element.
a new collection of type That resulting from applying the given function
f to each element of this map and collecting the results.
Builds a new collection by applying a function to all elements of this map.
Builds a new collection by applying a function to all elements of this map.
the element type of the returned collection.
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.
the function to apply to each element.
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.
a new collection of type That resulting from applying the given function
f to each element of this map and collecting the results.
Transforms this map by applying a function to every retrieved value.
Transforms this map by applying a function to every retrieved value.
the function used to transform values of this map.
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.
[use case] Finds the largest element.
Finds the largest element.
the largest element of this map with respect to the ordering cmp.
Finds the largest element.
Finds the largest element.
The type over which the ordering is defined.
An ordering to be used for comparing elements.
the largest element of this map with respect to the ordering cmp.
[use case] Finds the smallest element.
Finds the smallest element.
the smallest element of this map with respect to the ordering cmp.
Finds the smallest element.
Finds the smallest element.
The type over which the ordering is defined.
An ordering to be used for comparing elements.
the smallest element of this map with respect to the ordering cmp.
Displays all elements of this map in a string.
Displays all elements of this map in a string.
a string representation of this map. In the resulting string
the string representations (w.r.t. the method toString)
of all elements of this map follow each other without any
separator string.
Displays all elements of this map in a string using a separator string.
Displays all elements of this map in a string using a separator string.
the separator string.
a string representation of this map. In the resulting string
the string representations (w.r.t. the method toString)
of all elements of this map are separated by the string sep.
List(1, 2, 3).mkString("|") = "1|2|3"
Displays all elements of this map in a string using start, end, and separator strings.
Displays all elements of this map in a string using start, end, and separator strings.
the starting string.
the separator string.
the ending string.
a string representation of this 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 map are separated by
the string sep.
List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"
Equivalent to !(this eq that).
Equivalent to !(this eq that).
true if the argument is not a reference to the receiver object; false otherwise.
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.
Tests whether the map is not empty.
Tests whether the map is not empty.
true if the map contains at least one element, false otherwise.
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.
not specified by SLS as a member of AnyRef
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.
not specified by SLS as a member of AnyRef
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.
the argument type of the fallback function
the result type of the fallback function
the fallback function
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.
Returns a parallel implementation of this collection.
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.
a parallel implementation of this collection
The default par implementation uses the combiner provided by this method
to create a new parallel collection.
The default par implementation uses the combiner provided by this method
to create a new parallel collection.
a combiner for the parallel collection of type ParRepr
Partitions this map in two maps according to a predicate.
Partitions this map in two maps according to a predicate.
the predicate on which to partition.
a pair of maps: the first map consists of all elements that
satisfy the predicate p and the second map consists of all elements
that don't. The relative order of the elements in the resulting maps
is the same as in the original map.
[use case] Multiplies up the elements of this collection.
Multiplies up the elements of this collection.
the product of all elements of this map with respect to the * operator in num.
Multiplies up the elements of this collection.
Multiplies up the elements of this collection.
the result type of the * operator.
an implicit parameter defining a set of numeric operations
which includes the * operator to be used in forming the product.
the product of all elements of this map with respect to the * operator in num.
Reduces the elements of this map using the specified associative binary operator.
Reduces the elements of this map using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
A type parameter for the binary operator, a supertype of A.
A binary operator that must be associative.
The result of applying reduce operator op between all the elements if the map is nonempty.
if this map is empty.
Optionally applies a binary operator to all elements of this map, going left to right.
Optionally applies a binary operator to all elements of this 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.
the result type of the binary operator.
the binary operator.
an option value containing the result of reduceLeft(op) is this map is nonempty,
None otherwise.
Reduces the elements of this map, if any, using the specified associative binary operator.
Reduces the elements of this map, if any, using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
A type parameter for the binary operator, a supertype of A.
A binary operator that must be associative.
An option value containing result of applying reduce operator op between all
the elements if the collection is nonempty, and None otherwise.
Applies a binary operator to all elements of this map, going right to left.
Applies a binary operator to all elements of this 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.
the result type of the binary operator.
the binary operator.
the result of inserting op between consecutive elements of this map,
going right to left:
op(x,,1,,, op(x,,2,,, ..., op(x,,n-1,,, x,,n,,)...))
where x1, ..., xn are the elements of this map.
if this map is empty.
Optionally applies a binary operator to all elements of this map, going right to left.
Optionally applies a binary operator to all elements of this 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.
the result type of the binary operator.
the binary operator.
an option value containing the result of reduceRight(op) is this map is nonempty,
None otherwise.
The collection of type map underlying this TraversableLike object.
The collection of type map underlying this TraversableLike object.
By default this is implemented as the TraversableLike object itself,
but this can be overridden.
[use case] Checks if the other iterable collection contains the same elements in the same order as this map.
Checks if the other iterable collection contains the same elements in the same order as this map.
the collection to compare with.
true, if both collections contain the same elements in the same order, false otherwise.
Checks if the other iterable collection contains the same elements in the same order as this map.
Checks if the other iterable collection contains the same elements in the same order as this map.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the type of the elements of collection that.
the collection to compare with.
true, if both collections contain the same elements in the same order, false otherwise.
Computes a prefix scan of the elements of the collection.
Computes a prefix scan of the elements of the collection.
Note: The neutral element z may be applied more than once.
element type of the resulting collection
type of the resulting collection
neutral element for the operator op
the associative operator for the scan
combiner factory which provides a combiner
a new map containing the prefix scan of the elements in this map
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.
the type of the elements in the resulting collection
the actual type of the resulting collection
the initial value
the binary operator applied to the intermediate result and the element
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.
collection with intermediate results
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. The head of the collection is the last cummulative result.
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)
the type of the elements in the resulting collection
the actual type of the resulting collection
the initial value
the binary operator applied to the intermediate result and the element
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.
collection with intermediate results
A version of this collection with all of the operations implemented sequentially (i.
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.
a sequential view of the collection.
The size of this map.
The size of this map.
the number of elements in this map.
Selects an interval of elements.
Selects an interval of elements. The returned collection is made up
of all elements x which satisfy the invariant:
from <= indexOf(x) < until
Note: might return different results for different runs, unless the underlying collection type is ordered.
the lowest index to include from this map.
the highest index to EXCLUDE from this map.
a map containing the elements greater than or equal to
index from extending up to (but not including) index until
of this map.
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.)
the number of elements per group
An iterator producing maps of size size, except the
last and the only element will be truncated if there are
fewer elements than size.
Iterator#sliding
Splits this map into a prefix/suffix pair according to a predicate.
Splits this 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.
the test predicate
a pair consisting of the longest prefix of this map whose
elements all satisfy p, and the rest of this map.
Splits this map into two at a given position.
Splits this 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.
the position at which to split.
a pair of maps consisting of the first n
elements of this map, and the other elements.
Defines the prefix of this object's toString representation.
Defines the prefix of this object's toString representation.
a string representation which starts the result of toString
applied to this map. By default the string prefix is the
simple name of the collection class map.
[use case] Sums up the elements of this collection.
Sums up the elements of this collection.
the sum of all elements of this map with respect to the + operator in num.
Sums up the elements of this collection.
Sums up the elements of this collection.
the result type of the + operator.
an implicit parameter defining a set of numeric operations
which includes the + operator to be used in forming the sum.
the sum of all elements of this map with respect to the + operator in num.
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.
a map consisting of all elements of this map except the first one.
if the map is empty.
Iterates over the tails of this map.
Iterates over the tails of this map. The first value will be this
map and the final one will be an empty map, with the intervening
values the results of successive applications of tail.
an iterator over all the tails of this map
List(1,2,3).tails = Iterator(List(1,2,3), List(2,3), List(3), Nil)
Selects first n elements.
Selects first n elements.
Note: might return different results for different runs, unless the underlying collection type is ordered.
Tt number of elements to take from this map.
a map consisting only of the first n elements of this map,
or else the whole map, if it has less than n elements.
Selects last n elements.
Selects last n elements.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the number of elements to take
a map consisting only of the last n elements of this map, or else the
whole map, if it has less than n elements.
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.
The predicate used to test elements.
the longest prefix of this map whose elements all satisfy
the predicate p.
The underlying collection seen as an instance of Map.
The underlying collection seen as an instance of Map.
By default this is implemented as the current collection object itself,
but this can be overridden.
[use case] Converts this map to an array.
Converts this map to an array.
an array containing all elements of this map.
Converts this map to an array.
Converts this map to an array.
the type of the elements of the array. A ClassManifest for
this type must be available.
an array containing all elements of this map.
Converts this map to a mutable buffer.
Converts this map to a mutable buffer.
a buffer containing all elements of this map.
A conversion from collections of type Repr to Map objects.
A conversion from collections of type Repr to Map objects.
By default this is implemented as just a cast, but this can be overridden.
Converts this map to an indexed sequence.
Converts this map to an indexed sequence.
an indexed sequence containing all elements of this map.
Converts this map to an iterable collection.
Converts this 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).
an Iterable containing all elements of this map.
Returns an Iterator over the elements in this map.
Returns an Iterator over the elements in this map. Will return the same Iterator if this instance is already an Iterator.
an Iterator containing all elements of this map.
Converts this map to a list.
Converts this map to a list.
a list containing all elements of this map.
[use case] Converts this map to a map.
Converts this 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.
a map containing all elements of this map.
Converts this map to a map.
Converts this 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.
a map containing all elements of this map.
Converts this map to a sequence.
Converts this map to a sequence. As with toIterable, it's lazy
in this default implementation, as this TraversableOnce may be
lazy and unevaluated.
a sequence containing all elements of this map.
Converts this map to a set.
Converts this map to a set.
a set containing all elements of this map.
Converts this map to a stream.
Converts this map to a stream.
a stream containing all elements of this map.
Creates a String representation of this object.
Converts this map to an unspecified Traversable.
Converts this map to an unspecified Traversable. Will return the same collection if this instance is already Traversable.
a Traversable containing all elements of this map.
Transposes this map of traversable collections into a map of maps.
Transposes this map of traversable collections into a map of maps.
the type of the elements of each traversable collection.
an implicit conversion which asserts that the
element type of this map is a Traversable.
a two-dimensional map of maps which has as nth row the nth column of this map.
(Changed in version 2.9.0) transpose throws an IllegalArgumentException if collections are not uniformly sized.
if all collections in this map are not of the same size.
Converts this map of pairs into two collections of the first and second half of each pair.
Converts this map of pairs into two collections of the first and second half of each pair.
an implicit conversion which asserts that the element type of this map is a pair.
a pair maps, containing the first, respectively second half of each element pair of this map.
Converts this map of triples into three collections of the first, second, and third element of each triple.
Converts this map of triples into three collections of the first, second, and third element of each triple.
an implicit conversion which asserts that the element type of this map is a triple.
a triple maps, containing the first, second, respectively third member of each element triple of this map.
[use case] Creates a new map obtained by updating this map with a given key/value pair.
Creates a new map obtained by updating this map with a given key/value pair.
the key
the value
A new map with the new key/value mapping added to this map.
Creates a new map obtained by updating this map with a given key/value pair.
Creates a new map obtained by updating this map with a given key/value pair.
the type of the added value
the key
the value
A new map with the new key/value mapping added to this map.
Collects all values of this map in an iterable collection.
Collects all values of this map in an iterable collection.
the values of this map as an iterable.
Creates an iterator for all values in this map.
Creates an iterator for all values in this map.
an iterator over all values that are associated with some key in this map.
Creates a non-strict view of a slice of this map.
Creates a non-strict view of a slice of this map.
Note: the difference between view and slice is that view produces
a view of the current map, whereas slice produces a new 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.
the index of the first element of the view
the index of the element following the view
a non-strict view of a slice of this map, starting at index from
and extending up to (but not including) index until.
Creates a non-strict view of this map.
Creates a non-strict view of this map.
a non-strict view of this map.
Creates a non-strict filter of this map.
Creates a non-strict filter of this 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.
the predicate used to test elements.
an object of class WithFilter, which supports
map, flatMap, foreach, and withFilter operations.
All these operations apply to those elements of this map which
satisfy the predicate p.
[use case] Returns a map formed from this map and another iterable collection by combining corresponding elements in pairs.
Returns a map formed from this 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.
the type of the second half of the returned pairs
The iterable providing the second half of each result pair
a new collection of type That containing pairs consisting of
corresponding elements of this map and that. The length
of the returned collection is the minimum of the lengths of this map and that.
Returns a map formed from this map and another iterable collection by combining corresponding elements in pairs.
Returns a map formed from this 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.
the type of the first half of the returned pairs (this is always a supertype
of the collection's element type A).
the type of the second half of the returned pairs
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.
The iterable providing the second half of each result pair
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).
a new collection of type That containing pairs consisting of
corresponding elements of this map and that. The length
of the returned collection is the minimum of the lengths of this map and that.
[use case] Returns a map formed from this map and another iterable collection by combining corresponding elements in pairs.
Returns a map formed from this 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.
the iterable providing the second half of each result pair
the element to be used to fill up the result if this map is shorter than that.
the element to be used to fill up the result if that is shorter than this map.
a new collection of type That containing pairs consisting of
corresponding elements of this map and that. The length
of the returned collection is the maximum of the lengths of this map and that.
If this map is shorter than that, thisElem values are used to pad the result.
If that is shorter than this map, thatElem values are used to pad the result.
Returns a map formed from this map and another iterable collection by combining corresponding elements in pairs.
Returns a map formed from this 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.
the iterable providing the second half of each result pair
the element to be used to fill up the result if this map is shorter than that.
the element to be used to fill up the result if that is shorter than this map.
a new collection of type That containing pairs consisting of
corresponding elements of this map and that. The length
of the returned collection is the maximum of the lengths of this map and that.
If this map is shorter than that, thisElem values are used to pad the result.
If that is shorter than this map, thatElem values are used to pad the result.
[use case] Zips this map with its indices.
Zips this map with its indices.
A new collection of type That containing pairs consisting of all elements of this
map paired with their index. Indices start at 0.
Zips this map with its indices.
Zips this map with its indices.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the type of the first half of the returned pairs (this is always a supertype
of the collection's element type A).
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.
A new collection of type That containing pairs consisting of all elements of this
map paired with their index. Indices start at 0.
(Since version 2.8.0) use iterator' instead
(Since version 2.8.0) use head' instead
None if iterable is empty.
None if iterable is empty.
(Since version 2.8.0) use headOption' instead
(Since version 2.8.0) use mapValues' instead
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.
(Since version 2.8.0) use view' instead
This is a simple wrapper class for
scala.collection.Map. It is most useful for assembling customized map abstractions dynamically using object composition and forwarding.1.0, 21/07/2003
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