The type implementing this traversable
The type implementing this traversable
A class supporting filtered operations.
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
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 ==
[use case] Returns a new immutable iterable collection containing the elements from the left hand operand followed by the elements from the right hand operand.
Returns a new immutable iterable collection containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the immutable iterable collection is the most specific superclass encompassing the element types of the two operands.
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 traversable to append.
a new immutable iterable collection which contains all elements of this immutable iterable collection
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.
Mnemonic: the COLon is on the side of the new COLlection type.
Example:
scala> val x = List(1) x: List[Int] = List(1) scala> val y = LinkedList(2) y: scala.collection.mutable.LinkedList[Int] = LinkedList(2) scala> val z = x ++: y z: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2)
This overload exists because: for the implementation of ++:
we should
reuse that of ++
because many collections override it with more
efficient versions.
Since TraversableOnce
has no ++
method, we have to implement that
directly, but Traversable
and down can use the overload.
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 immutable iterable collection followed by all elements of that
.
[use case] 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.
Mnemonic: the COLon is on the side of the new COLlection type.
Example:
scala> val x = List(1) x: List[Int] = List(1) scala> val y = LinkedList(2) y: scala.collection.mutable.LinkedList[Int] = LinkedList(2) scala> val z = x ++: y z: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2)
the element type of the returned collection.
the traversable to append.
a new immutable iterable collection which contains all elements of this immutable iterable collection
followed by all elements of that
.
Applies a binary operator to a start value and all elements of this immutable iterable collection, going left to right.
Applies a binary operator to a start value and all elements of this immutable iterable collection, going left to right.
Note: /:
is alternate syntax for foldLeft
; z /: xs
is the same as
xs foldLeft z
.
Examples:
Note that the folding function used to compute b is equivalent to that used to compute c.
scala> val a = 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: 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 immutable iterable collection,
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 immutable iterable collection.
Applies a binary operator to all elements of this immutable iterable collection and a start value, going right to left.
Applies a binary operator to all elements of this immutable iterable collection and a start value, going right to left.
Note: :\
is alternate syntax for foldRight
; xs :\ z
is the same as
xs foldRight z
.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.
Examples:
Note that the folding function used to compute b is equivalent to that used to compute c.
scala> val a = 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 immutable iterable collection,
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 immutable iterable collection.
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.
Appends all elements of this immutable iterable collection to a string builder.
Appends all elements of this immutable iterable collection to a string builder.
The written text consists of the string representations (w.r.t. the method
toString
) of all elements of this immutable iterable collection 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 immutable iterable collection to a string builder using a separator string.
Appends all elements of this immutable iterable collection to a string builder using a separator string.
The written text consists of the string representations (w.r.t. the method toString
)
of all elements of this immutable iterable collection, 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.
Appends all elements of this immutable iterable collection to a string builder using start, end, and separator strings.
Appends all elements of this immutable iterable collection 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 immutable iterable collection 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.
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
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 immutable iterable collection should be compared
true
, if this immutable iterable collection 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 immutable iterable collection on which the function is defined.
Builds a new collection by applying a partial function to all elements of this immutable iterable collection on which the function is defined.
the element type of the returned collection.
the partial function which filters and maps the immutable iterable collection.
a new immutable iterable collection 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.
Finds the first element of the immutable iterable collection for which the given partial function is defined, and applies the partial function to it.
Finds the first element of the immutable iterable collection for which the given partial function is defined, and applies the partial function to it.
Note: may not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered.
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 immutable.Iterable
.
The factory companion object that builds instances of class immutable.Iterable
.
(or its Iterable
superclass where class immutable.Iterable
is not a Seq
.)
[use case] Copies elements of this immutable iterable collection to an array.
Copies elements of this immutable iterable collection to an array.
Fills the given array xs
with at most len
elements of
this immutable iterable collection, starting at position start
.
Copying will stop once either the end of the current immutable iterable collection is reached,
or the end of the 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 values of this immutable iterable collection to an array.
Copies values of this immutable iterable collection to an array.
Fills the given array xs
with values of this immutable iterable collection.
Copying will stop once either the end of the current immutable iterable collection is reached,
or the end of the array is reached.
Note: will not terminate for infinite-sized collections.
the array to fill.
[use case] Copies values of this immutable iterable collection to an array.
Copies values of this immutable iterable collection to an array.
Fills the given array xs
with values of this immutable iterable collection, beginning at index start
.
Copying will stop once either the end of the current immutable iterable collection 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.
Copies all elements of this immutable iterable collection to a buffer.
Copies all elements of this immutable iterable collection to a buffer.
Note: will not terminate for infinite-sized collections.
The buffer to which elements are copied.
Counts the number of elements in the immutable iterable collection which satisfy a predicate.
Counts the number of elements in the immutable iterable collection 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 immutable iterable collection.
a immutable iterable collection consisting of all elements of this immutable iterable collection except the first n
ones, or else the
empty immutable iterable collection, if this immutable iterable collection 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 immutable iterable collection consisting of all elements of this immutable iterable collection except the last n
ones, or else the
empty immutable iterable collection, if this immutable iterable collection 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 longest suffix of this immutable iterable collection whose first element
does not satisfy the predicate p
.
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 immutable iterable collection.
Tests whether a predicate holds for some of the elements of this immutable iterable collection.
Note: may not terminate for infinite-sized collections.
the predicate used to test elements.
true
if the given predicate p
holds for some of the
elements of this immutable iterable collection, otherwise false
.
Selects all elements of this immutable iterable collection which satisfy a predicate.
Selects all elements of this immutable iterable collection which satisfy a predicate.
the predicate used to test elements.
a new immutable iterable collection consisting of all elements of this immutable iterable collection that satisfy the given
predicate p
. The order of the elements is preserved.
Selects all elements of this immutable iterable collection which do not satisfy a predicate.
Selects all elements of this immutable iterable collection which do not satisfy a predicate.
the predicate used to test elements.
a new immutable iterable collection consisting of all elements of this immutable iterable collection 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 immutable iterable collection satisfying a predicate, if any.
Finds the first element of the immutable iterable collection satisfying a predicate, if any.
Note: may not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the predicate used to test elements.
an option value containing the first element in the immutable iterable collection
that satisfies p
, or None
if none exists.
[use case] Builds a new collection by applying a function to all elements of this immutable iterable collection and using the elements of the resulting collections.
Builds a new collection by applying a function to all elements of this immutable iterable collection 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 immutable iterable collection. 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 function to apply to each element.
a new immutable iterable collection resulting from applying the given collection-valued function
f
to each element of this immutable iterable collection and concatenating the results.
[use case] Converts this immutable iterable collection of traversable collections into a immutable iterable collection formed by the elements of these traversable collections.
Converts this immutable iterable collection of traversable collections into a immutable iterable collection formed by the elements of these traversable collections.
The resulting collection's type will be guided by the static type of immutable iterable collection. For example:
val xs = List(Set(1, 2, 3), Set(1, 2, 3)) // xs == List(1, 2, 3, 1, 2, 3) val ys = Set(List(1, 2, 3), List(3, 2, 1)) // ys == Set(1, 2, 3)
the type of the elements of each traversable collection.
a new immutable iterable collection resulting from concatenating all element immutable iterable collections.
Folds the elements of this immutable iterable collection using the specified associative binary operator.
Folds the elements of this immutable iterable collection 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 immutable iterable collection, going left to right.
Applies a binary operator to a start value and all elements of this immutable iterable collection, going left to right.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.
the result type of the binary operator.
the start value.
the binary operator.
the result of inserting op
between consecutive elements of this immutable iterable collection,
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 immutable iterable collection.
Applies a binary operator to all elements of this immutable iterable collection and a start value, going right to left.
Applies a binary operator to all elements of this immutable iterable collection and a start value, going right to left.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.
the result type of the binary operator.
the start value.
the binary operator.
the result of inserting op
between consecutive elements of this immutable iterable collection,
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 immutable iterable collection.
Tests whether a predicate holds for all elements of this immutable iterable collection.
Tests whether a predicate holds for all elements of this immutable iterable collection.
Note: may not terminate for infinite-sized collections.
the predicate used to test elements.
true
if the given predicate p
holds for all elements
of this immutable iterable collection, otherwise false
.
[use case] Applies a function f
to all elements of this immutable iterable collection.
Applies a function f
to all elements of this immutable iterable collection.
Note: this method underlies the implementation of most other bulk operations. Subclasses should re-implement this method if a more efficient implementation exists.
the function that is applied for its side-effect to every element.
The result of function f
is discarded.
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).
The generic builder that builds instances of immutable.Iterable
at arbitrary element types.
The generic builder that builds instances of immutable.Iterable
at arbitrary element types.
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
Partitions this immutable iterable collection into a map of immutable iterable collections according to some discriminator function.
Partitions this immutable iterable collection into a map of immutable iterable collections according to some discriminator function.
Note: this method is not re-implemented by views. This means when applied to a view it will always force the view and return a new immutable iterable collection.
the type of keys returned by the discriminator function.
the discriminator function.
A map from keys to immutable iterable collections such that the following invariant holds:
(xs partition f)(k) = xs filter (x => f(x) == k)
That is, every key k
is bound to a immutable iterable collection of those elements x
for which f(x)
equals k
.
Partitions elements in fixed size immutable iterable collections.
Partitions elements in fixed size immutable iterable collections.
the number of elements per group
An iterator producing immutable iterable collections of size size
, except the
last will be truncated if the elements don't divide evenly.
scala.collection.Iterator, method grouped
Tests whether this immutable iterable collection is known to have a finite size.
Tests whether this immutable iterable collection is known to have a finite size.
All strict collections are known to have finite size. For a non-strict
collection such as Stream
, the predicate returns true
if all
elements have been computed. It returns false
if the stream is
not yet evaluated to the end.
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 immutable iterable collection.
Selects the first element of this immutable iterable collection.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the first element of this immutable iterable collection.
if the immutable iterable collection 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 immutable iterable collection 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 immutable iterable collection consisting of all elements of this immutable iterable collection except the last one.
if the immutable iterable collection is empty.
Iterates over the inits of this immutable iterable collection.
Iterates over the inits of this immutable iterable collection. The first value will be this
immutable iterable collection and the final one will be an empty immutable iterable collection, with the intervening
values the results of successive applications of init
.
an iterator over all the inits of this immutable iterable collection
List(1,2,3).inits = Iterator(List(1,2,3), List(1,2), List(1), Nil)
Tests whether this immutable iterable collection is empty.
Tests whether this immutable iterable collection is empty.
true
if the immutable iterable collection 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 immutable iterable collection can be repeatedly traversed.
Tests whether this immutable iterable collection can be repeatedly traversed.
true
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 immutable iterable collection.
If the immutable iterable collection 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 immutable iterable collection$ if it is nonempty,
None
if it is empty.
[use case] Builds a new collection by applying a function to all elements of this immutable iterable collection.
Builds a new collection by applying a function to all elements of this immutable iterable collection.
the element type of the returned collection.
the function to apply to each element.
a new immutable iterable collection resulting from applying the given function
f
to each element of this immutable iterable collection and collecting the results.
[use case] Finds the largest element.
Finds the largest element.
the largest element of this immutable iterable collection.
[use case] Finds the smallest element.
Finds the smallest element.
the smallest element of this immutable iterable collection
Displays all elements of this immutable iterable collection in a string.
Displays all elements of this immutable iterable collection in a string.
a string representation of this immutable iterable collection. In the resulting string
the string representations (w.r.t. the method toString
)
of all elements of this immutable iterable collection follow each other without any
separator string.
Displays all elements of this immutable iterable collection in a string using a separator string.
Displays all elements of this immutable iterable collection in a string using a separator string.
the separator string.
a string representation of this immutable iterable collection. In the resulting string
the string representations (w.r.t. the method toString
)
of all elements of this immutable iterable collection are separated by the string sep
.
List(1, 2, 3).mkString("|") = "1|2|3"
Displays all elements of this immutable iterable collection in a string using start, end, and separator strings.
Displays all elements of this immutable iterable collection in a string using start, end, and separator strings.
the starting string.
the separator string.
the ending string.
a string representation of this immutable iterable collection. The resulting string
begins with the string start
and ends with the string
end
. Inside, the string representations (w.r.t. the method
toString
) of all elements of this immutable iterable collection 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.
The builder that builds instances of type immutable.Iterable
[A]
The builder that builds instances of type immutable.Iterable
[A]
Tests whether the immutable iterable collection is not empty.
Tests whether the immutable iterable collection is not empty.
true
if the immutable iterable collection 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
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 immutable iterable collection in two immutable iterable collections according to a predicate.
Partitions this immutable iterable collection in two immutable iterable collections according to a predicate.
the predicate on which to partition.
a pair of immutable iterable collections: the first immutable iterable collection consists of all elements that
satisfy the predicate p
and the second immutable iterable collection consists of all elements
that don't. The relative order of the elements in the resulting immutable iterable collections
is the same as in the original immutable iterable collection.
[use case] Multiplies up the elements of this collection.
Multiplies up the elements of this collection.
the product of all elements in this immutable iterable collection of numbers of type Int
.
Instead of Int
, any other type T
with an implicit Numeric[T]
implementation
can be used as element type of the immutable iterable collection and as result type of product
.
Examples of such types are: Long
, Float
, Double
, BigInt
.
Reduces the elements of this immutable iterable collection using the specified associative binary operator.
Reduces the elements of this immutable iterable collection 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 immutable iterable collection is nonempty.
if this immutable iterable collection is empty.
Applies a binary operator to all elements of this immutable iterable collection, going left to right.
Applies a binary operator to all elements of this immutable iterable collection, going left to right.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.
the result type of the binary operator.
the binary operator.
the result of inserting op
between consecutive elements of this immutable iterable collection,
going left to right:
op( op( ... op(x_1, x_2) ..., x_{n-1}), x_n)
where x1, ..., xn
are the elements of this immutable iterable collection.
if this immutable iterable collection is empty.
Optionally applies a binary operator to all elements of this immutable iterable collection, going left to right.
Optionally applies a binary operator to all elements of this immutable iterable collection, going left to right.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.
the result type of the binary operator.
the binary operator.
an option value containing the result of reduceLeft(op)
is this immutable iterable collection is nonempty,
None
otherwise.
Reduces the elements of this immutable iterable collection, if any, using the specified associative binary operator.
Reduces the elements of this immutable iterable collection, 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 immutable iterable collection, going right to left.
Applies a binary operator to all elements of this immutable iterable collection, going right to left.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.
the result type of the binary operator.
the binary operator.
the result of inserting op
between consecutive elements of this immutable iterable collection,
going right to left:
op(x_1, op(x_2, ..., op(x_{n-1}, x_n)...))
where x1, ..., xn
are the elements of this immutable iterable collection.
if this immutable iterable collection is empty.
Optionally applies a binary operator to all elements of this immutable iterable collection, going right to left.
Optionally applies a binary operator to all elements of this immutable iterable collection, going right to left.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.
the result type of the binary operator.
the binary operator.
an option value containing the result of reduceRight(op)
is this immutable iterable collection is nonempty,
None
otherwise.
The collection of type immutable iterable collection underlying this TraversableLike
object.
The collection of type immutable iterable collection 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 immutable iterable collection.
Checks if the other iterable collection contains the same elements in the same order as this immutable iterable collection.
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.
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 immutable iterable collection containing the prefix scan of the elements in this immutable iterable collection
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 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 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 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
(Changed in version 2.9.0) The behavior of scanRight
has changed. The previous behavior can be reproduced with scanRight.reverse.
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 immutable iterable collection.
The size of this immutable iterable collection.
Note: will not terminate for infinite-sized collections.
the number of elements in this immutable iterable collection.
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.
a immutable iterable collection containing the elements greater than or equal to
index from
extending up to (but not including) index until
of this immutable iterable collection.
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
the distance between the first elements of successive groups (defaults to 1)
An iterator producing immutable iterable collections of size size
, except the
last and the only element will be truncated if there are
fewer elements than size.
scala.collection.Iterator, method sliding
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 immutable iterable collections of size size
, except the
last and the only element will be truncated if there are
fewer elements than size.
scala.collection.Iterator, method sliding
Splits this immutable iterable collection into a prefix/suffix pair according to a predicate.
Splits this immutable iterable collection into a prefix/suffix pair according to a predicate.
Note: c span p
is equivalent to (but possibly more efficient than)
(c takeWhile p, c dropWhile p)
, provided the evaluation of the
predicate p
does not cause any side-effects.
Note: might return different results for different runs, unless the underlying collection type is ordered.
a pair consisting of the longest prefix of this immutable iterable collection whose
elements all satisfy p
, and the rest of this immutable iterable collection.
Splits this immutable iterable collection into two at a given position.
Splits this immutable iterable collection into two at a given position.
Note: c splitAt n
is equivalent to (but possibly more efficient than)
(c take n, c drop n)
.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the position at which to split.
a pair of immutable iterable collections consisting of the first n
elements of this immutable iterable collection, 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 immutable iterable collection. By default the string prefix is the
simple name of the collection class immutable iterable collection.
[use case] Sums up the elements of this collection.
Sums up the elements of this collection.
the sum of all elements in this immutable iterable collection of numbers of type Int
.
Instead of Int
, any other type T
with an implicit Numeric[T]
implementation
can be used as element type of the immutable iterable collection 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 immutable iterable collection consisting of all elements of this immutable iterable collection except the first one.
if the immutable iterable collection is empty.
Iterates over the tails of this immutable iterable collection.
Iterates over the tails of this immutable iterable collection. The first value will be this
immutable iterable collection and the final one will be an empty immutable iterable collection, with the intervening
values the results of successive applications of tail
.
an iterator over all the tails of this immutable iterable collection
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.
the number of elements to take from this immutable iterable collection.
a immutable iterable collection consisting only of the first n
elements of this immutable iterable collection,
or else the whole immutable iterable collection, 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 immutable iterable collection consisting only of the last n
elements of this immutable iterable collection, or else the
whole immutable iterable collection, 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 longest prefix of this immutable iterable collection whose elements all satisfy
the predicate p
.
The underlying collection seen as an instance of
.immutable.Iterable
The underlying collection seen as an instance of
.
By default this is implemented as the current collection object itself,
but this can be overridden.
immutable.Iterable
[use case] Converts this immutable iterable collection into another by copying all elements.
Converts this immutable iterable collection 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 immutable iterable collection.
[use case] Converts this immutable iterable collection to an array.
Converts this immutable iterable collection to an array.
Note: will not terminate for infinite-sized collections.
an array containing all elements of this immutable iterable collection.
An ClassTag
must be available for the element type of this immutable iterable collection.
Converts this immutable iterable collection to a mutable buffer.
Converts this immutable iterable collection to a mutable buffer.
Note: will not terminate for infinite-sized collections.
a buffer containing all elements of this immutable iterable collection.
A conversion from collections of type Repr
to
objects.immutable.Iterable
A conversion from collections of type Repr
to
objects.
By default this is implemented as just a cast, but this can be overridden.
immutable.Iterable
Converts this immutable iterable collection to an indexed sequence.
Converts this immutable iterable collection to an indexed sequence.
Note: will not terminate for infinite-sized collections.
an indexed sequence containing all elements of this immutable iterable collection.
Converts this immutable iterable collection to an iterable collection.
Converts this immutable iterable collection to an iterable collection. Note that
the choice of target Iterable
is lazy in this default implementation
as this TraversableOnce
may be lazy and unevaluated (i.e. it may
be an iterator which is only traversable once).
Note: will not terminate for infinite-sized collections.
an Iterable
containing all elements of this immutable iterable collection.
Returns an Iterator over the elements in this immutable iterable collection.
Returns an Iterator over the elements in this immutable iterable collection. 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 immutable iterable collection.
Converts this immutable iterable collection to a list.
Converts this immutable iterable collection to a list.
Note: will not terminate for infinite-sized collections.
a list containing all elements of this immutable iterable collection.
[use case] Converts this immutable iterable collection to a map.
Converts this immutable iterable collection 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 immutable iterable collection.
Converts this immutable iterable collection to a sequence.
Converts this immutable iterable collection to a sequence. As with toIterable
, it's lazy
in this default implementation, as this TraversableOnce
may be
lazy and unevaluated.
Note: will not terminate for infinite-sized collections.
a sequence containing all elements of this immutable iterable collection.
Converts this immutable iterable collection to a set.
Converts this immutable iterable collection to a set.
Note: will not terminate for infinite-sized collections.
a set containing all elements of this immutable iterable collection.
Converts this immutable iterable collection to a stream.
Converts this immutable iterable collection to a stream.
Note: will not terminate for infinite-sized collections.
a stream containing all elements of this immutable iterable collection.
Converts this immutable iterable collection to a string.
Converts this immutable iterable collection to a string.
a string representation of this collection. By default this
string consists of the stringPrefix
of this immutable iterable collection, followed
by all elements separated by commas and enclosed in parentheses.
Converts this immutable iterable collection to an unspecified Traversable.
Converts this immutable iterable collection 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 immutable iterable collection.
Converts this immutable iterable collection to a Vector.
Converts this immutable iterable collection to a Vector.
Note: will not terminate for infinite-sized collections.
a vector containing all elements of this immutable iterable collection.
Transposes this immutable iterable collection of traversable collections into a immutable iterable collection of immutable iterable collections.
Transposes this immutable iterable collection of traversable collections into a immutable iterable collection of immutable iterable collections.
the type of the elements of each traversable collection.
an implicit conversion which asserts that the
element type of this immutable iterable collection is a Traversable
.
a two-dimensional immutable iterable collection of immutable iterable collections which has as nth row the nth column of this immutable iterable collection.
(Changed in version 2.9.0) transpose
throws an IllegalArgumentException
if collections are not uniformly sized.
if all collections in this immutable iterable collection are not of the same size.
Converts this immutable iterable collection of pairs into two collections of the first and second half of each pair.
Converts this immutable iterable collection of pairs into two collections of the first and second half of each pair.
the type of the first half of the element pairs
the type of the second half of the element pairs
an implicit conversion which asserts that the element type of this immutable iterable collection is a pair.
a pair immutable iterable collections, containing the first, respectively second half of each element pair of this immutable iterable collection.
Converts this immutable iterable collection of triples into three collections of the first, second, and third element of each triple.
Converts this immutable iterable collection of triples into three collections of the first, second, and third element of each triple.
the type of the first member of the element triples
the type of the second member of the element triples
the type of the third member of the element triples
an implicit conversion which asserts that the element type of this immutable iterable collection is a triple.
a triple immutable iterable collections, containing the first, second, respectively third member of each element triple of this immutable iterable collection.
Creates a non-strict view of a slice of this immutable iterable collection.
Creates a non-strict view of a slice of this immutable iterable collection.
Note: the difference between view
and slice
is that view
produces
a view of the current immutable iterable collection, whereas slice
produces a new immutable iterable collection.
Note: view(from, to)
is equivalent to view.slice(from, to)
Note: might return different results for different runs, unless the underlying collection type is ordered.
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 immutable iterable collection, starting at index from
and extending up to (but not including) index until
.
Creates a non-strict view of this immutable iterable collection.
Creates a non-strict view of this immutable iterable collection.
a non-strict view of this immutable iterable collection.
Creates a non-strict filter of this immutable iterable collection.
Creates a non-strict filter of this immutable iterable collection.
Note: the difference between c filter p
and c withFilter p
is that
the former creates a new collection, whereas the latter only
restricts the domain of subsequent map
, flatMap
, foreach
,
and withFilter
operations.
Note: might return different results for different runs, unless the underlying collection type is ordered.
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 immutable iterable collection
which satisfy the predicate p
.
[use case] Returns a immutable iterable collection formed from this immutable iterable collection and another iterable collection by combining corresponding elements in pairs.
Returns a immutable iterable collection formed from this immutable iterable collection 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 immutable iterable collection containing pairs consisting of
corresponding elements of this immutable iterable collection and that
. The length
of the returned collection is the minimum of the lengths of this immutable iterable collection and that
.
[use case] Returns a immutable iterable collection formed from this immutable iterable collection and another iterable collection by combining corresponding elements in pairs.
Returns a immutable iterable collection formed from this immutable iterable collection 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 immutable iterable collection is shorter than that
.
the element to be used to fill up the result if that
is shorter than this immutable iterable collection.
a new immutable iterable collection containing pairs consisting of
corresponding elements of this immutable iterable collection and that
. The length
of the returned collection is the maximum of the lengths of this immutable iterable collection and that
.
If this immutable iterable collection is shorter than that
, thisElem
values are used to pad the result.
If that
is shorter than this immutable iterable collection, thatElem
values are used to pad the result.
[use case] Zips this immutable iterable collection with its indices.
Zips this immutable iterable collection with its indices.
Note: might return different results for different runs, unless the underlying collection type is ordered.
A new immutable iterable collection containing pairs consisting of all elements of this
immutable iterable collection paired with their index. Indices start at 0
.
List("a", "b", "c").zipWithIndex = List(("a", 0), ("b", 1), ("c", 2))
(iterable: MonadOps[A]).filter(p)
(iterable: MonadOps[A]).flatMap(f)
(iterable: MonadOps[A]).map(f)
(iterable: StringAdd).self
(iterable: StringFormat).self
(iterable: MonadOps[A]).withFilter(p)
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
(Since version 2.10.0) use fold instead
(iterable: ArrowAssoc[Iterable[A]]).x
(Since version 2.10.0) Use leftOfArrow
instead
(iterable: Ensuring[Iterable[A]]).x
(Since version 2.10.0) Use resultOfEnsuring
instead
A base trait for iterable collections that are guaranteed immutable.
This is a base trait for all immutable Scala collections that define an
iterator
method to step through one-by-one the collection's elements. Implementations of this trait need to provide a concrete method with signature:def iterator: Iterator[A]
They also need to provide a method
newBuilder
which creates a builder for collections of the same kind.This trait implements
Iterable
'sforeach
method by stepping through all elements usingiterator
. Subclasses should re-implementforeach
with something more efficient, if possible.This trait adds methods
iterator
,sameElements
,takeRight
,dropRight
to the methods inherited from traitTraversable
.Note: This trait replaces every method that uses
break
inTraversableLike
by an iterator version.