GenTraversableOnce
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package collection
Applies a binary operator to a start value and all elements of this collection or iterator, going left to right.
Applies a binary operator to a start value and all elements of this collection or iterator, 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 result type of the binary operator.
the start value.
the binary operator.
the result of inserting op between consecutive elements of this collection or iterator,
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 collection or iterator.
Applies a binary operator to all elements of this collection or iterator and a start value, going right to left.
Applies a binary operator to all elements of this collection or iterator 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 result type of the binary operator.
the start value
the binary operator
the result of inserting op between consecutive elements of this collection or iterator,
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 collection or iterator.
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) 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
Counts the number of elements in the collection or iterator which satisfy a predicate.
Counts the number of elements in the collection or iterator which satisfy a predicate.
the predicate used to test elements.
the number of elements satisfying the predicate p.
Finds the first element of the collection or iterator satisfying a predicate, if any.
Finds the first element of the collection or iterator satisfying a predicate, if any.
Note: may not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the predicate used to test elements.
an option value containing the first element in the collection or iterator
that satisfies p, or None if none exists.
Folds the elements of this collection or iterator using the specified associative binary operator.
Folds the elements of this collection or iterator 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 collection or iterator, going left to right.
Applies a binary operator to a start value and all elements of this collection or iterator, 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 result type of the binary operator.
the start value.
the binary operator.
the result of inserting op between consecutive elements of this collection or iterator,
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 collection or iterator.
Applies a binary operator to all elements of this collection or iterator and a start value, going right to left.
Applies a binary operator to all elements of this collection or iterator 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 result type of the binary operator.
the start value.
the binary operator.
the result of inserting op between consecutive elements of this collection or iterator,
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 collection or iterator.
Returns the runtime class representation of the object.
Returns the runtime class representation of the object.
a class object corresponding to the runtime type of the receiver.
Tests whether the collection or iterator is empty.
Tests whether the collection or iterator is empty.
true if the collection or iterator contains no elements, false otherwise.
Tests whether this collection or iterator can be repeatedly traversed.
Tests whether this collection or iterator can be repeatedly traversed. Always true for Traversables and false for Iterators unless overridden.
true if it is repeatedly traversable, false otherwise.
Displays all elements of this collection or iterator in a string.
Displays all elements of this collection or iterator in a string.
a string representation of this collection or iterator. In the resulting string
the string representations (w.r.t. the method toString)
of all elements of this collection or iterator follow each other without any
separator string.
Displays all elements of this collection or iterator in a string using a separator string.
Displays all elements of this collection or iterator in a string using a separator string.
the separator string.
a string representation of this collection or iterator. In the resulting string
the string representations (w.r.t. the method toString)
of all elements of this collection or iterator are separated by the string sep.
List(1, 2, 3).mkString("|") = "1|2|3"
Displays all elements of this collection or iterator in a string using start, end, and separator strings.
Displays all elements of this collection or iterator in a string using start, end, and separator strings.
the starting string.
the separator string.
the ending string.
a string representation of this collection or iterator. 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 collection or iterator are separated by
the string sep.
List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"
Tests whether the collection or iterator is not empty.
Tests whether the collection or iterator is not empty.
true if the collection or iterator contains at least one element, false otherwise.
Reduces the elements of this collection or iterator using the specified associative binary operator.
Reduces the elements of this collection or iterator 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 collection or iterator is nonempty.
UnsupportedOperationException
if this collection or iterator is empty.
Optionally applies a binary operator to all elements of this collection or iterator, going left to right.
Optionally applies a binary operator to all elements of this collection or iterator, 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 result type of the binary operator.
the binary operator.
an option value containing the result of reduceLeft(op) if this collection or iterator is nonempty,
None otherwise.
Reduces the elements of this collection or iterator, if any, using the specified associative binary operator.
Reduces the elements of this collection or iterator, if any, using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
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 collection or iterator, going right to left.
Applies a binary operator to all elements of this collection or iterator, 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 result type of the binary operator.
the binary operator.
the result of inserting op between consecutive elements of this collection or iterator,
going right to left:
op(x_1, op(x_2, ..., op(x_{n-1}, x_n)...)) where x1, ..., xn are the elements of this collection or iterator.
UnsupportedOperationException if this collection or iterator is empty.
Optionally applies a binary operator to all elements of this collection or iterator, going right to left.
Optionally applies a binary operator to all elements of this collection or iterator, 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 result type of the binary operator.
the binary operator.
an option value containing the result of reduceRight(op) if this collection or iterator is nonempty,
None otherwise.
The size of this collection or iterator.
The size of this collection or iterator.
Note: will not terminate for infinite-sized collections.
the number of elements in this collection or iterator.
Uses the contents of this collection or iterator to create a new mutable buffer.
Uses the contents of this collection or iterator to create a new mutable buffer.
Note: will not terminate for infinite-sized collections.
a buffer containing all elements of this collection or iterator.
Converts this collection or iterator to an indexed sequence.
Converts this collection or iterator to an indexed sequence.
Note: will not terminate for infinite-sized collections.
an indexed sequence containing all elements of this collection or iterator.
Converts this collection or iterator to an iterable collection.
Converts this collection or iterator 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 collection or iterator.
Returns an Iterator over the elements in this collection or iterator.
Returns an Iterator over the elements in this collection or iterator. 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 collection or iterator.
Converts this collection or iterator to a list.
Converts this collection or iterator to a list.
Note: will not terminate for infinite-sized collections.
a list containing all elements of this collection or iterator.
Converts this collection or iterator to a sequence.
Converts this collection or iterator 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 collection or iterator.
Converts this collection or iterator to a set.
Converts this collection or iterator to a set.
Note: will not terminate for infinite-sized collections.
a set containing all elements of this collection or iterator.
Converts this collection or iterator to a stream.
Converts this collection or iterator to a stream.
a stream containing all elements of this collection or iterator.
Converts this collection or iterator to an unspecified Traversable.
Converts this collection or iterator 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 collection or iterator.
Converts this collection or iterator to a Vector.
Converts this collection or iterator to a Vector.
Note: will not terminate for infinite-sized collections.
a vector containing all elements of this collection or iterator.
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 and null.
Equivalent to x.hashCode except for boxed numeric types and null.
For numerics, it returns a hash value which is consistent
with value equality: if two value type instances compare
as true, then ## will produce the same hash value for each
of them.
For null returns a hashcode where null.hashCode throws a
NullPointerException.
a hash value consistent with ==
Test two objects for equality.
Test two objects for equality.
The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).
true if the receiver object is equivalent to the argument; false otherwise.
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.
ClassCastException if the receiver object is not an instance of the erasure of type T0.
[use case] Copies values of this collection or iterator to an array.
Copies values of this collection or iterator to an array.
Fills the given array xs with values of this collection or iterator, beginning at index start.
Copying will stop once either the end of the current collection or iterator is reached,
or the end of the array is reached.
Note: will not terminate for infinite-sized collections.
the array to fill.
the starting index.
[use case] Copies values of this collection or iterator to an array.
Copies values of this collection or iterator to an array.
Fills the given array xs with values of this collection or iterator.
Copying will stop once either the end of the current collection or iterator is reached,
or the end of the array is reached.
Note: will not terminate for infinite-sized collections.
the array to fill.
Compares the receiver object (this) with the argument object (that) for equivalence.
Compares the receiver object (this) with the argument object (that) for equivalence.
Any implementation of this method should be an equivalence relation:
x of type Any, x.equals(x) should return true.x and y of type Any, x.equals(y) should return true if and
only if y.equals(x) returns true.x, y, and z of type AnyRef if x.equals(y) returns true and
y.equals(z) returns true, then x.equals(z) should return true. If you override this method, you should verify that your implementation remains an equivalence relation.
Additionally, when overriding this method it is usually necessary to override hashCode to ensure that
objects which are "equal" (o1.equals(o2) returns true) hash to the same scala.Int.
(o1.hashCode.equals(o2.hashCode)).
true if the receiver object is equivalent to the argument; false otherwise.
Returns string formatted according to given format string.
Returns string formatted according to given format string.
Format strings are as for String.format
(@see java.lang.String.format).
Calculate a hash code value for the object.
Calculate a hash code value for the object.
The default hashing algorithm is platform dependent.
Note that it is allowed for two objects to have identical hash codes (o1.hashCode.equals(o2.hashCode)) yet
not be equal (o1.equals(o2) returns false). A degenerate implementation could always return 0.
However, it is required that if two objects are equal (o1.equals(o2) returns true) that they have
identical hash codes (o1.hashCode.equals(o2.hashCode)). Therefore, when overriding this method, be sure
to verify that the behavior is consistent with the equals method.
the hash code value for this object.
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.
[use case] Finds the largest element.
Finds the largest element.
the largest element of this collection or iterator.
[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 collection or iterator with the largest value measured by function f.
[use case] Finds the smallest element.
Finds the smallest element.
the smallest element of this collection or iterator
[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 collection or iterator with the smallest value measured by function f.
[use case] Multiplies up the elements of this collection.
Multiplies up the elements of this collection.
the product of all elements in this collection or iterator 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 collection or iterator and as result type of product.
Examples of such types are: Long, Float, Double, BigInt.
[use case] Sums up the elements of this collection.
Sums up the elements of this collection.
the sum of all elements in this collection or iterator 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 collection or iterator and as result type of sum.
Examples of such types are: Long, Float, Double, BigInt.
[use case] Converts this collection or iterator into another by copying all elements.
Converts this collection or iterator 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 collection or iterator.
[use case] Converts this collection or iterator to an array.
Converts this collection or iterator to an array.
Note: will not terminate for infinite-sized collections.
an array containing all elements of this collection or iterator.
An ClassTag must be available for the element type of this collection or iterator.
[use case] Converts this collection or iterator to a map.
Converts this collection or iterator 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 collection or iterator.
Returns a string representation of the object.
Returns a string representation of the object.
The default representation is platform dependent.
a string representation of the object.
A template trait for all traversable-once objects which may be traversed in parallel.
Methods in this trait are either abstract or can be implemented in terms of other methods.