scala.collection.parallel.mutable
ParMapLike
Related Doc:
package mutable
Standard accessor task that iterates over the elements of the collection.
Standard accessor task that iterates over the elements of the collection.
type of the result of this method (R for result).
the representation type of the task at hand.
Performs two tasks in parallel, and waits for both to finish.
Performs two tasks in parallel, and waits for both to finish.
Sequentially performs one task after another.
Sequentially performs one task after another.
adds a single element to this parallel map .
adds a single element to this parallel map .
the parallel map itself
Removes a single element from this parallel map .
Removes a single element from this parallel map .
the parallel map itself
Clears the parallel map 's contents.
Clears the parallel map 's contents. After this operation, the parallel map is empty.
The size of this general collection.
The size of this general collection.
Note: will not terminate for infinite-sized collections.
the number of elements in this general collection.
Creates a new parallel iterator used to traverse the elements of this parallel collection.
Creates a new parallel iterator used to traverse the elements of this parallel collection.
This iterator is more specific than the iterator of the returned by iterator, and augmented
with additional accessor and transformer methods.
a parallel iterator
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 general collection. By default the string prefix is the
simple name of the collection class general collection.
[use case] Returns a new parallel map containing the elements from the left hand operand followed by the elements from the right hand operand.
Returns a new parallel map containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the parallel map is the most specific superclass encompassing the element types of the two operands.
Example:
scala> val a = List(1) a: List[Int] = List(1) scala> val b = List(2) b: List[Int] = List(2) scala> val c = a ++ b c: List[Int] = List(1, 2) scala> val d = List('a') d: List[Char] = List(a) scala> val e = c ++ d e: List[AnyVal] = List(1, 2, a)
the element type of the returned collection.
the traversable to append.
a new parallel map
which contains all elements of this parallel map
followed by all elements of that.
adds all elements produced by a TraversableOnce to this growable collection.
adds all elements produced by a TraversableOnce to this growable collection.
the TraversableOnce producing the elements to add.
the growable collection itself.
adds two or more elements to this growable collection.
adds two or more elements to this growable collection.
the first element to add.
the second element to add.
the remaining elements to add.
the growable collection itself
Removes all elements produced by an iterator from this shrinkable collection.
Removes all elements produced by an iterator from this shrinkable collection.
the iterator producing the elements to remove.
the shrinkable collection itself
Removes two or more elements from this shrinkable collection.
Removes two or more elements from this shrinkable collection.
the first element to remove.
the second element to remove.
the remaining elements to remove.
the shrinkable collection itself
Applies a binary operator to a start value and all elements of this parallel iterable, going left to right.
Applies a binary operator to a start value and all elements of this parallel iterable, 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.
the start value.
the binary operator.
the result of inserting op between consecutive elements of this parallel iterable,
going left to right with the start value z on the left:
op(...op(op(z, x_1), x_2), ..., x_n)
where x1, ..., xn are the elements of this parallel iterable.
Applies a binary operator to all elements of this parallel iterable and a start value, going right to left.
Applies a binary operator to all elements of this parallel iterable 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
the start value
the binary operator
the result of inserting op between consecutive elements of this parallel iterable,
going right to left with the start value z on the right:
op(x_1, op(x_2, ... op(x_n, z)...))
where x1, ..., xn are the elements of this parallel iterable.
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 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 set, while combop
would concatenate two sets 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) and may be evaluated
more than once
an operator used to accumulate results within a partition
an associative operator used to combine results from different partitions
[use case] Builds a new collection by applying a partial function to all elements of this parallel map
Builds a new collection by applying a partial function to all elements of this parallel map
on which the function is defined.
the element type of the returned collection.
the partial function which filters and maps the parallel map .
a new parallel 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.
Creates a combiner factory.
Creates a combiner factory. Each combiner factory instance is used once per invocation of a parallel transformer method for a single collection.
The default combiner factory creates a new combiner every time it
is requested, unless the combiner is thread-safe as indicated by its
canBeShared method. In this case, the method returns a factory which
returns the same combiner each time. This is typically done for
concurrent parallel collections, the combiners of which allow
thread safe access.
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 the elements of this parallel map to an array.
Copies the elements of this parallel map
to an array.
Fills the given array xs with at most len elements of
this parallel map
, starting at position start.
Copying will stop once either the end of the current parallel map
is reached,
or the end of the target array is reached, or len elements have been copied.
Note: will not terminate for infinite-sized collections.
the array to fill.
the starting index.
the maximal number of elements to copy.
[use case] Copies the elements of this parallel map to an array.
Copies the elements of this parallel map
to an array.
Fills the given array xs with values of this parallel map
, beginning at index start.
Copying will stop once either the end of the current parallel map
is reached,
or the end of the target array is reached.
Note: will not terminate for infinite-sized collections.
the array to fill.
the starting index.
[use case] Copies the elements of this parallel map to an array.
Copies the elements of this parallel map
to an array.
Fills the given array xs with values of this parallel map
.
Copying will stop once either the end of the current parallel map
is reached,
or the end of the target array is reached.
Note: will not terminate for infinite-sized collections.
the array to fill.
Counts the number of elements in the parallel iterable which satisfy a predicate.
Counts the number of elements in the parallel iterable which satisfy a predicate.
the predicate used to test elements.
the number of elements satisfying the predicate p.
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 parallel iterable.
a parallel iterable consisting of all elements of this parallel iterable except the first n ones, or else the
empty parallel iterable, if this parallel iterable has less than n elements.
Drops all elements in the longest prefix of elements that satisfy the predicate, and returns a collection composed of the remaining elements.
Drops all elements in the longest prefix of elements that satisfy the predicate, and returns a collection composed of the remaining elements.
This method will use indexFlag signalling capabilities. This means
that splitters may set and read the indexFlag state.
The index flag is initially set to maximum integer value.
the predicate used to test the elements
a collection composed of all the elements after the longest prefix of elements
in this parallel iterable that satisfy the predicate pred
Compares two maps structurally; i.e., checks if all mappings contained in this map are also contained in the other map, and vice versa.
Compares two maps structurally; i.e., checks if all mappings contained in this map are also contained in the other map, and vice versa.
the other map
true if both maps contain exactly the
same mappings, false otherwise.
Tests whether a predicate holds for some element of this parallel iterable.
Tests whether a predicate holds for some element of this parallel iterable.
This method will use abort signalling capabilities. This means
that splitters may send and read abort signals.
a predicate used to test elements
true if p holds for some element, false otherwise
Selects all elements of this parallel iterable which satisfy a predicate.
Selects all elements of this parallel iterable which satisfy a predicate.
the predicate used to test elements.
a new parallel iterable consisting of all elements of this parallel iterable that satisfy the given
predicate p. Their order may not be 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 parallel iterable which do not satisfy a predicate.
Selects all elements of this parallel iterable which do not satisfy a predicate.
the predicate used to test elements.
a new parallel iterable consisting of all elements of this parallel iterable that do not satisfy the given
predicate p. Their order may not be preserved.
Finds some element in the collection for which the predicate holds, if such an element exists.
Finds some element in the collection for which the predicate holds, if such an element exists. The element may not necessarily be the first such element in the iteration order.
If there are multiple elements obeying the predicate, the choice is nondeterministic.
This method will use abort signalling capabilities. This means
that splitters may send and read abort signals.
predicate used to test the elements
an option value with the element if such an element exists, or None otherwise
[use case] Builds a new collection by applying a function to all elements of this parallel map
Builds a new collection by applying a function to all elements of this parallel 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 parallel 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)
the element type of the returned collection.
the function to apply to each element.
a new parallel map
resulting from applying the given collection-valued function
f to each element of this parallel map
and concatenating the results.
Folds the elements of this sequence using the specified associative binary operator.
Folds the elements of this sequence using the specified associative binary operator. The order in which the elements are reduced is unspecified and may be nondeterministic.
Note this method has a different signature than the foldLeft
and foldRight methods of the trait Traversable.
The result of folding may only be a supertype of this parallel collection's
type parameter T.
a type parameter for the binary operator, a supertype of T.
a neutral element for the fold operation, it may be added to the result
an arbitrary number of times, not changing 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 parallel iterable, going left to right.
Applies a binary operator to a start value and all elements of this parallel iterable, 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.
the start value.
the binary operator.
the result of inserting op between consecutive elements of this parallel iterable,
going left to right with the start value z on the left:
op(...op(z, x_1), x_2, ..., x_n)
where x1, ..., xn are the elements of this parallel iterable.
Returns z if this parallel iterable is empty.
Applies a binary operator to all elements of this parallel iterable and a start value, going right to left.
Applies a binary operator to all elements of this parallel iterable 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.
the start value.
the binary operator.
the result of inserting op between consecutive elements of this parallel iterable,
going right to left with the start value z on the right:
op(x_1, op(x_2, ... op(x_n, z)...))
where x1, ..., xn are the elements of this parallel iterable.
Returns z if this parallel iterable is empty.
Tests whether a predicate holds for all elements of this parallel iterable.
Tests whether a predicate holds for all elements of this parallel iterable.
This method will use abort signalling capabilities. This means
that splitters may send and read abort signals.
a predicate used to test elements
true if p holds for all elements, false otherwise
Applies a function f to all the elements of parallel iterable in an undefined order.
Applies a function f to all the elements of parallel iterable in an undefined order.
the result type of the function applied to each element, which is always discarded
function applied to each element
[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.
Partitions this parallel iterable into a map of parallel iterables according to some discriminator function.
Partitions this parallel iterable into a map of parallel iterables 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 parallel iterable.
the type of keys returned by the discriminator function.
the discriminator function.
A map from keys to parallel iterables 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 parallel iterable of those elements x
for which f(x) equals k.
Tests whether this parallel iterable is known to have a finite size.
Tests whether this parallel iterable 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.
true if this collection is known to have finite size,
false otherwise.
Selects the first element of this parallel iterable.
Selects the first element of this parallel iterable.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the first element of this parallel iterable.
NoSuchElementException if the parallel iterable 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 parallel iterable 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 parallel iterable consisting of all elements of this parallel iterable except the last one.
UnsupportedOperationException if the parallel iterable is empty.
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 the parallel iterable is empty.
Tests whether the parallel iterable is empty.
Note: Implementations in subclasses that are not repeatedly traversable must take
care not to consume any elements when isEmpty is called.
true if the parallel iterable contains no elements, false otherwise.
Denotes whether this parallel collection has strict splitters.
Denotes whether this parallel collection has strict splitters.
This is true in general, and specific collection instances may choose to
override this method. Such collections will fail to execute methods
which rely on splitters being strict, i.e. returning a correct value
in the remaining method.
This method helps ensure that such failures occur on method invocations, rather than later on and in unpredictable ways.
Tests whether this parallel iterable can be repeatedly traversed.
Tests whether this parallel iterable can be repeatedly traversed.
true
Creates a new split iterator used to traverse the elements of this collection.
Creates a new split iterator used to traverse the elements of this collection.
By default, this method is implemented in terms of the protected splitter method.
a split iterator
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 parallel iterable.
NoSuchElementException If the parallel iterable 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 parallel iterable$ if it is nonempty,
None if it is empty.
[use case] Builds a new collection by applying a function to all elements of this parallel map .
Builds a new collection by applying a function to all elements of this parallel map .
the element type of the returned collection.
the function to apply to each element.
a new parallel map
resulting from applying the given function
f to each element of this parallel 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 parallel map .
[use case] Finds the first element which yields the largest value measured by function f.
Finds the first element which yields the largest value measured by function f.
The result type of the function f.
The measuring function.
the first element of this parallel map with the largest value measured by function f.
[use case] Finds the smallest element.
Finds the smallest element.
the smallest element of this parallel map
[use case] Finds the first element which yields the smallest value measured by function f.
Finds the first element which yields the smallest value measured by function f.
The result type of the function f.
The measuring function.
the first element of this parallel map with the smallest value measured by function f.
Displays all elements of this parallel iterable in a string.
Displays all elements of this parallel iterable in a string.
a string representation of this parallel iterable. In the resulting string
the string representations (w.r.t. the method toString)
of all elements of this parallel iterable follow each other without any
separator string.
Displays all elements of this parallel iterable in a string using a separator string.
Displays all elements of this parallel iterable in a string using a separator string.
the separator string.
a string representation of this parallel iterable. In the resulting string
the string representations (w.r.t. the method toString)
of all elements of this parallel iterable are separated by the string sep.
List(1, 2, 3).mkString("|") = "1|2|3"
Displays all elements of this parallel iterable in a string using start, end, and separator strings.
Displays all elements of this parallel iterable in a string using start, end, and separator strings.
the starting string.
the separator string.
the ending string.
a string representation of this parallel iterable. 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 parallel iterable are separated by
the string sep.
List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"
Tests whether the parallel iterable is not empty.
Tests whether the parallel iterable is not empty.
true if the parallel iterable contains at least one element, false otherwise.
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 parallel iterable in two parallel iterables according to a predicate.
Partitions this parallel iterable in two parallel iterables according to a predicate.
the predicate on which to partition.
a pair of parallel iterables: the first parallel iterable consists of all elements that
satisfy the predicate p and the second parallel iterable consists of all elements
that don't. The relative order of the elements in the resulting parallel iterables
may not be preserved.
[use case] Multiplies up the elements of this collection.
Multiplies up the elements of this collection.
the product of all elements in this parallel map
of numbers of type Int.
Instead of Int, any other type T with an implicit Numeric[T] implementation
can be used as element type of the parallel map
and as result type of product.
Examples of such types are: Long, Float, Double, BigInt.
Reduces the elements of this sequence using the specified associative binary operator.
Reduces the elements of this sequence using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
Note this method has a different signature than the reduceLeft
and reduceRight methods of the trait Traversable.
The result of reducing may only be a supertype of this parallel collection's
type parameter T.
A type parameter for the binary operator, a supertype of T.
A binary operator that must be associative.
The result of applying reduce operator op between all the elements if the collection is nonempty.
UnsupportedOperationException
if this parallel iterable is empty.
Optionally applies a binary operator to all elements of this parallel iterable, going left to right.
Optionally applies a binary operator to all elements of this parallel iterable, 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.
the binary operator.
an option value containing the result of reduceLeft(op) if this parallel iterable is nonempty,
None otherwise.
Optionally reduces the elements of this sequence using the specified associative binary operator.
Optionally reduces the elements of this sequence using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
Note this method has a different signature than the reduceLeftOption
and reduceRightOption methods of the trait Traversable.
The result of reducing may only be a supertype of this parallel collection's
type parameter T.
A type parameter for the binary operator, a supertype of T.
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 parallel iterable, going right to left.
Applies a binary operator to all elements of this parallel iterable, 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.
the binary operator.
the result of inserting op between consecutive elements of this parallel iterable,
going right to left:
op(x_1, op(x_2, ..., op(x_{n-1}, x_n)...)) where x1, ..., xn are the elements of this parallel iterable.
UnsupportedOperationException if this parallel iterable is empty.
Optionally applies a binary operator to all elements of this parallel iterable, going right to left.
Optionally applies a binary operator to all elements of this parallel iterable, 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.
the binary operator.
an option value containing the result of reduceRight(op) if this parallel iterable is nonempty,
None otherwise.
Optionally reuses an existing combiner for better performance.
Optionally reuses an existing combiner for better performance. By default it doesn't - subclasses may override this behaviour.
The provided combiner oldc that can potentially be reused will be either some combiner from the previous computational task, or None if there
was no previous phase (in which case this method must return newc).
The combiner that is the result of the previous task, or None if there was no previous task.
The new, empty combiner that can be used.
Either newc or oldc.
[use case] Checks if the other iterable collection contains the same elements in the same order as this parallel map .
Checks if the other iterable collection contains the same elements in the same order as this parallel map .
Note: might return different results for different runs, unless the underlying collection type is ordered.
Note: will not terminate for infinite-sized collections.
the collection to compare with.
true, if both collections contain the same elements in the same order, false otherwise.
[use case] 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.
neutral element for the operator op
the associative operator for the scan
a new parallel map containing the prefix scan of the elements in this parallel map
Produces a collection containing cumulative results of applying the operator going left to right.
Produces a collection containing cumulative results of applying the operator going left to right.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered.
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 cumulative results of applying the operator going right to left.
Produces a collection containing cumulative results of applying the operator going right to left. The head of the collection is the last cumulative result.
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)
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
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 parallel iterable.
the lowest index to EXCLUDE from this parallel iterable.
a parallel iterable containing the elements greater than or equal to
index from extending up to (but not including) index until
of this parallel iterable.
Splits this parallel iterable into a prefix/suffix pair according to a predicate.
Splits this parallel iterable into a prefix/suffix pair according to a predicate.
This method will use indexFlag signalling capabilities. This means
that splitters may set and read the indexFlag state.
The index flag is initially set to maximum integer value.
the predicate used to test the elements
a pair consisting of the longest prefix of the collection for which all
the elements satisfy pred, and the rest of the collection
Splits this parallel iterable into two at a given position.
Splits this parallel iterable 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 parallel iterables consisting of the first n
elements of this parallel iterable, and the other elements.
[use case] Sums up the elements of this collection.
Sums up the elements of this collection.
the sum of all elements in this parallel map
of numbers of type Int.
Instead of Int, any other type T with an implicit Numeric[T] implementation
can be used as element type of the parallel map
and as result type of sum.
Examples of such types are: Long, Float, Double, BigInt.
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 parallel iterable consisting of all elements of this parallel iterable except the first one.
UnsupportedOperationException if the parallel iterable is empty.
Selects first n elements.
Selects first n elements.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the number of elements to take from this parallel iterable.
a parallel iterable consisting only of the first n elements of this parallel iterable,
or else the whole parallel iterable, if it has less than n elements.
Takes the longest prefix of elements that satisfy the predicate.
Takes the longest prefix of elements that satisfy the predicate.
This method will use indexFlag signalling capabilities. This means
that splitters may set and read the indexFlag state.
The index flag is initially set to maximum integer value.
the predicate used to test the elements
the longest prefix of this parallel iterable of elements that satisfy the predicate pred
The task support object which is responsible for scheduling and load-balancing tasks to processors.
The task support object which is responsible for scheduling and load-balancing tasks to processors.
Changes the task support object which is responsible for scheduling and load-balancing tasks to processors.
Changes the task support object which is responsible for scheduling and load-balancing tasks to processors.
A task support object can be changed in a parallel collection after it has been created, but only during a quiescent period, i.e. while there are no concurrent invocations to parallel collection methods.
Here is a way to change the task support of a parallel collection:
import scala.collection.parallel._ val pc = mutable.ParArray(1, 2, 3) pc.tasksupport = new ForkJoinTaskSupport( new scala.concurrent.forkjoin.ForkJoinPool(2))
[use case] Converts this parallel map into another by copying all elements.
Converts this parallel map into another by copying all elements.
Note: will not terminate for infinite-sized collections.
The collection type to build.
a new collection containing all elements of this parallel map .
[use case] Converts this parallel map to an array.
Converts this parallel map to an array.
Note: will not terminate for infinite-sized collections.
an array containing all elements of this parallel map
.
An ClassTag must be available for the element type of this parallel map
.
Uses the contents of this parallel iterable to create a new mutable buffer.
Uses the contents of this parallel iterable to create a new mutable buffer.
Note: will not terminate for infinite-sized collections.
a buffer containing all elements of this parallel iterable.
Converts this parallel iterable to an indexed sequence.
Converts this parallel iterable to an indexed sequence.
Note: will not terminate for infinite-sized collections.
an indexed sequence containing all elements of this parallel iterable.
Converts this parallel iterable to an iterable collection.
Converts this parallel iterable 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.
an Iterable containing all elements of this parallel iterable.
Returns an Iterator over the elements in this parallel iterable.
Returns an Iterator over the elements in this parallel iterable. Will return the same Iterator if this instance is already an Iterator.
Note: will not terminate for infinite-sized collections.
an Iterator containing all elements of this parallel iterable.
Converts this parallel iterable to a list.
Converts this parallel iterable to a list.
Note: will not terminate for infinite-sized collections.
a list containing all elements of this parallel iterable.
[use case] Converts this parallel map to a map.
Converts this parallel 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.
Note: will not terminate for infinite-sized collections.
a map of type immutable.Map[T, U]
containing all key/value pairs of type (T, U) of this parallel map
.
Converts this parallel iterable to a sequence.
Converts this parallel iterable 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.
a sequence containing all elements of this parallel iterable.
Converts this parallel iterable to a set.
Converts this parallel iterable to a set.
Note: will not terminate for infinite-sized collections.
a set containing all elements of this parallel iterable.
Converts this parallel iterable to a stream.
Converts this parallel iterable to a stream.
a stream containing all elements of this parallel iterable.
Converts this parallel iterable to an unspecified Traversable.
Converts this parallel iterable to an unspecified Traversable. Will return the same collection if this instance is already Traversable.
Note: will not terminate for infinite-sized collections.
a Traversable containing all elements of this parallel iterable.
Converts this parallel iterable to a Vector.
Converts this parallel iterable to a Vector.
Note: will not terminate for infinite-sized collections.
a vector containing all elements of this parallel iterable.
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.
[use case] Returns a parallel map formed from this parallel map and another iterable collection by combining corresponding elements in pairs.
Returns a parallel map formed from this parallel 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 second half of the returned pairs
The iterable providing the second half of each result pair
a new parallel map
containing pairs consisting of
corresponding elements of this parallel map
and that. The length
of the returned collection is the minimum of the lengths of this parallel map
and that.
[use case] Returns a parallel map formed from this parallel map and another iterable collection by combining corresponding elements in pairs.
Returns a parallel map formed from this parallel 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 type of the second half of the returned pairs
The iterable providing the second half of each result pair
the element to be used to fill up the result if this parallel map
is shorter than that.
the element to be used to fill up the result if that is shorter than this parallel map
.
a new parallel map
containing pairs consisting of
corresponding elements of this parallel map
and that. The length
of the returned collection is the maximum of the lengths of this parallel map
and that.
If this parallel map
is shorter than that, thisElem values are used to pad the result.
If that is shorter than this parallel map
, thatElem values are used to pad the result.
[use case] Zips this parallel map with its indices.
Zips this parallel map with its indices.
Note: might return different results for different runs, unless the underlying collection type is ordered.
A new parallel map
containing pairs consisting of all elements of this
parallel map
paired with their index. Indices start at 0.
List("a", "b", "c").zipWithIndex = List(("a", 0), ("b", 1), ("c", 2))
(Since version 2.11.0) Use .seq.view instead
A template trait for mutable parallel maps. This trait is to be mixed in with concrete parallel maps to override the representation type.
The higher-order functions passed to certain operations may contain side-effects. Since implementations of bulk operations may not be sequential, this means that side-effects may not be predictable and may produce data-races, deadlocks or invalidation of state if care is not taken. It is up to the programmer to either avoid using side-effects or to use some form of synchronization when accessing mutable data.
the key type of the map
the value type of the map