The type implementing this traversable
The type implementing this traversable
A class supporting filtered operations.
Selects an element by its index in the immutable sequence.
Selects an element by its index in the immutable sequence.
Example:
scala> val x = LinkedList(1, 2, 3, 4, 5) x: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2, 3, 4, 5) scala> x(3) res1: Int = 4
The index to select.
the element of this immutable sequence at index idx, where 0 indicates the first element.
if idx does not satisfy 0 <= idx < length.
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
The length of the immutable sequence.
The length of the immutable sequence.
Note: will not terminate for infinite-sized collections.
Note: xs.length and xs.size yield the same result.
the number of elements in this immutable sequence.
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 sequence containing the elements from the left hand operand followed by the elements from the right hand operand.
Returns a new immutable sequence containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the immutable sequence 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 sequence which contains all elements of this immutable sequence
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 the new element type B.
a new collection of type That which contains all elements
of this immutable sequence 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 sequence which contains all elements of this immutable sequence
followed by all elements of that.
[use case] A copy of the immutable sequence with an element prepended.
A copy of the immutable sequence with an element prepended.
Note that :-ending operators are right associative (see example).
A mnemonic for +: vs. :+ is: the COLon goes on the COLlection side.
Also, the original immutable sequence is not modified, so you will want to capture the result.
Example:
scala> val x = LinkedList(1) x: scala.collection.mutable.LinkedList[Int] = LinkedList(1) scala> val y = 2 +: x y: scala.collection.mutable.LinkedList[Int] = LinkedList(2, 1) scala> println(x) LinkedList(1)
the prepended element
a new immutable sequence consisting of elem followed
by all elements of this immutable sequence.
Applies a binary operator to a start value and all elements of this immutable sequence, going left to right.
Applies a binary operator to a start value and all elements of this immutable sequence, 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.
the result type of the binary operator.
the start value.
the binary operator.
the result of inserting op between consecutive elements of this immutable sequence,
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 sequence.
[use case] A copy of this immutable sequence with an element appended.
A copy of this immutable sequence with an element appended.
A mnemonic for +: vs. :+ is: the COLon goes on the COLlection side.
Note: will not terminate for infinite-sized collections.
Example:
scala> import scala.collection.mutable.LinkedList import scala.collection.mutable.LinkedList scala> val a = LinkedList(1) a: scala.collection.mutable.LinkedList[Int] = LinkedList(1) scala> val b = a :+ 2 b: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2) scala> println(a) LinkedList(1)
the appended element
a new immutable sequence consisting of
all elements of this immutable sequence followed by elem.
Applies a binary operator to all elements of this immutable sequence and a start value, going right to left.
Applies a binary operator to all elements of this immutable sequence 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.
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 sequence,
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 sequence.
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 sequence to a string builder.
Appends all elements of this immutable sequence to a string builder.
The written text consists of the string representations (w.r.t. the method
toString) of all elements of this immutable sequence 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 sequence to a string builder using a separator string.
Appends all elements of this immutable sequence 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 sequence, 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 sequence to a string builder using start, end, and separator strings.
Appends all elements of this immutable sequence 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 sequence 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
Composes this partial function with a transformation function that gets applied to results of this partial function.
Composes this partial function with a transformation function that gets applied to results of this partial function.
the result type of the transformation function.
the transformation function
a partial function with the same domain as this partial function, which maps
arguments x to k(this(x)).
Applies this partial function to the given argument when it is contained in the function domain.
Applies this partial function to the given argument when it is contained in the function domain. Applies fallback function where this partial function is not defined.
Note that expression pf.applyOrElse(x, default) is equivalent to
if(pf isDefinedAt x) pf(x) else default(x)
except that applyOrElse method can be implemented more efficiently.
For all partial function literals compiler generates applyOrElse implementation which
avoids double evaluation of pattern matchers and guards.
This makes applyOrElse the basis for the efficient implementation for many operations and scenarios, such as:
orElse/andThen chains does not lead to
excessive apply/isDefinedAt evaluationlift and unlift do not evaluate source functions twice on each invocationrunWith allows efficient imperative-style combining of partial functions
with conditionally applied actions For non-literal partial function classes with nontrivial isDefinedAt method
it is recommended to override applyOrElse with custom implementation that avoids
double isDefinedAt evaluation. This may result in better performance
and more predictable behavior w.r.t. side effects.
the function argument
the fallback function
the result of this function or fallback function application.
2.10
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 sequence should be compared
true, if this immutable sequence 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 sequence on which the function is defined.
Builds a new collection by applying a partial function to all elements of this immutable sequence on which the function is defined.
the element type of the returned collection.
the partial function which filters and maps the immutable sequence.
a new immutable sequence 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 sequence for which the given partial function is defined, and applies the partial function to it.
Finds the first element of the immutable sequence for which the given partial function is defined, and applies the partial function to it.
Note: may not terminate for infinite-sized collections.
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)
Iterates over combinations.
Iterates over combinations.
An Iterator which traverses the possible n-element combinations of this immutable sequence.
"abbbc".combinations(2) = Iterator(ab, ac, bb, bc)
The factory companion object that builds instances of class immutable.Seq.
The factory companion object that builds instances of class immutable.Seq.
(or its Iterable superclass where class immutable.Seq is not a Seq.)
Composes two instances of Function1 in a new Function1, with this function applied last.
Composes two instances of Function1 in a new Function1, with this function applied last.
the type to which function g can be applied
a function A => T1
a new function f such that f(x) == apply(g(x))
Tests whether this immutable sequence contains a given value as an element.
Tests whether this immutable sequence contains a given value as an element.
Note: may not terminate for infinite-sized collections.
the element to test.
true if this immutable sequence has an element that is equal (as
determined by ==) to elem, false otherwise.
Tests whether this immutable sequence contains a given sequence as a slice.
Tests whether this immutable sequence contains a given sequence as a slice.
Note: may not terminate for infinite-sized collections.
the sequence to test
true if this immutable sequence contains a slice with the same elements
as that, otherwise false.
[use case] Copies elements of this immutable sequence to an array.
Copies elements of this immutable sequence to an array.
Fills the given array xs with at most len elements of
this immutable sequence, starting at position start.
Copying will stop once either the end of the current immutable sequence 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 sequence to an array.
Copies values of this immutable sequence to an array.
Fills the given array xs with values of this immutable sequence.
Copying will stop once either the end of the current immutable sequence 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 sequence to an array.
Copies values of this immutable sequence to an array.
Fills the given array xs with values of this immutable sequence, beginning at index start.
Copying will stop once either the end of the current immutable sequence 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 sequence to a buffer.
Copies all elements of this immutable sequence to a buffer.
Note: will not terminate for infinite-sized collections.
The buffer to which elements are copied.
Tests whether every element of this immutable sequence relates to the corresponding element of another sequence by satisfying a test predicate.
Tests whether every element of this immutable sequence relates to the corresponding element of another sequence by satisfying a test predicate.
the type of the elements of that
the other sequence
the test predicate, which relates elements from both sequences
true if both sequences have the same length and
p(x, y) is true for all corresponding elements x of this immutable sequence
and y of that, otherwise false.
Counts the number of elements in the immutable sequence which satisfy a predicate.
Counts the number of elements in the immutable sequence which satisfy a predicate.
the predicate used to test elements.
the number of elements satisfying the predicate p.
[use case] Computes the multiset difference between this immutable sequence and another sequence.
Computes the multiset difference between this immutable sequence and another sequence.
Note: will not terminate for infinite-sized collections.
the sequence of elements to remove
a new immutable sequence which contains all elements of this immutable sequence
except some of occurrences of elements that also appear in that.
If an element value x appears
n times in that, then the first n occurrences of x will not form
part of the result, but any following occurrences will.
Builds a new immutable sequence from this immutable sequence without any duplicate elements.
Builds a new immutable sequence from this immutable sequence without any duplicate elements.
Note: will not terminate for infinite-sized collections.
A new immutable sequence which contains the first occurrence of every element of this immutable sequence.
Selects all elements except first n ones.
Selects all elements except first n ones.
the number of elements to drop from this immutable sequence.
a immutable sequence consisting of all elements of this immutable sequence except the first n ones, or else the
empty immutable sequence, if this immutable sequence has less than n elements.
Selects all elements except last n ones.
Selects all elements except last n ones.
The number of elements to take
a immutable sequence consisting of all elements of this immutable sequence except the last n ones, or else the
empty immutable sequence, if this immutable sequence has less than n elements.
Drops longest prefix of elements that satisfy a predicate.
Drops longest prefix of elements that satisfy a predicate.
the longest suffix of this immutable sequence whose first element
does not satisfy the predicate p.
Tests whether this immutable sequence ends with the given sequence.
Tests whether this immutable sequence ends with the given sequence.
Note: will not terminate for infinite-sized collections.
the sequence to test
true if this immutable sequence has that as a suffix, false otherwise.
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 equals method for arbitrary sequences.
The equals method for arbitrary sequences. Compares this sequence to some other object.
The object to compare the sequence to
true if that is a sequence that has the same elements as
this sequence in the same order, false otherwise
Tests whether a predicate holds for some of the elements of this immutable sequence.
Tests whether a predicate holds for some of the elements of this immutable sequence.
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 sequence, otherwise false.
Selects all elements of this immutable sequence which satisfy a predicate.
Selects all elements of this immutable sequence which satisfy a predicate.
the predicate used to test elements.
a new immutable sequence consisting of all elements of this immutable sequence that satisfy the given
predicate p. The order of the elements is preserved.
Selects all elements of this immutable sequence which do not satisfy a predicate.
Selects all elements of this immutable sequence which do not satisfy a predicate.
the predicate used to test elements.
a new immutable sequence consisting of all elements of this immutable sequence 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 sequence satisfying a predicate, if any.
Finds the first element of the immutable sequence satisfying a predicate, if any.
Note: may not terminate for infinite-sized collections.
the predicate used to test elements.
an option value containing the first element in the immutable sequence
that satisfies p, or None if none exists.
[use case] Builds a new collection by applying a function to all elements of this immutable sequence and using the elements of the resulting collections.
Builds a new collection by applying a function to all elements of this immutable sequence 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 sequence. 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 sequence resulting from applying the given collection-valued function
f to each element of this immutable sequence and concatenating the results.
[use case] Converts this immutable sequence of traversable collections into a immutable sequence formed by the elements of these traversable collections.
Converts this immutable sequence of traversable collections into a immutable sequence formed by the elements of these traversable collections.
The resulting collection's type will be guided by the static type of immutable sequence. 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 sequence resulting from concatenating all element immutable sequences.
Folds the elements of this immutable sequence using the specified associative binary operator.
Folds the elements of this immutable sequence 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 sequence, going left to right.
Applies a binary operator to a start value and all elements of this immutable sequence, going left to right.
Note: will not terminate for infinite-sized collections.
the result type of the binary operator.
the start value.
the binary operator.
the result of inserting op between consecutive elements of this immutable sequence,
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 sequence.
Applies a binary operator to all elements of this immutable sequence and a start value, going right to left.
Applies a binary operator to all elements of this immutable sequence and a start value, going right to left.
Note: will not terminate for infinite-sized collections.
the result type of the binary operator.
the start value.
the binary operator.
the result of inserting op between consecutive elements of this immutable sequence,
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 sequence.
Tests whether a predicate holds for all elements of this immutable sequence.
Tests whether a predicate holds for all elements of this immutable sequence.
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 sequence, otherwise false.
[use case] Applies a function f to all elements of this immutable sequence.
Applies a function f to all elements of this immutable sequence.
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.Seq
at arbitrary element types.
The generic builder that builds instances of immutable.Seq
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 sequence into a map of immutable sequences according to some discriminator function.
Partitions this immutable sequence into a map of immutable sequences 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 sequence.
the type of keys returned by the discriminator function.
the discriminator function.
A map from keys to immutable sequences 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 sequence of those elements x
for which f(x) equals k.
Partitions elements in fixed size immutable sequences.
Partitions elements in fixed size immutable sequences.
the number of elements per group
An iterator producing immutable sequences 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 sequence is known to have a finite size.
Tests whether this immutable sequence 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.
Hashcodes for immutable.Seq produce a value from the hashcodes of all the
elements of the immutable sequence.
Hashcodes for immutable.Seq produce a value from the hashcodes of all the
elements of the immutable sequence.
the hash code value for this object.
Selects the first element of this immutable sequence.
Selects the first element of this immutable sequence.
the first element of this immutable sequence.
if the immutable sequence is empty.
Optionally selects the first element.
Optionally selects the first element.
the first element of this immutable sequence if it is nonempty,
None if it is empty.
[use case] Finds index of first occurrence of some value in this immutable sequence after or at some start index.
Finds index of first occurrence of some value in this immutable sequence after or at some start index.
Note: may not terminate for infinite-sized collections.
the element value to search for.
the start index
the index >= from of the first element of this immutable sequence that is equal (as determined by ==)
to elem, or -1, if none exists.
[use case] Finds index of first occurrence of some value in this immutable sequence.
Finds index of first occurrence of some value in this immutable sequence.
Note: may not terminate for infinite-sized collections.
the element value to search for.
the index of the first element of this immutable sequence that is equal (as determined by ==)
to elem, or -1, if none exists.
Finds first index after or at a start index where this immutable sequence contains a given sequence as a slice.
Finds first index after or at a start index where this immutable sequence contains a given sequence as a slice.
Note: may not terminate for infinite-sized collections.
the sequence to test
the start index
the first index >= from such that the elements of this immutable sequence starting at this index
match the elements of sequence that, or -1 of no such subsequence exists.
Finds first index where this immutable sequence contains a given sequence as a slice.
Finds first index where this immutable sequence contains a given sequence as a slice.
Note: may not terminate for infinite-sized collections.
the sequence to test
the first index such that the elements of this immutable sequence starting at this index
match the elements of sequence that, or -1 of no such subsequence exists.
Finds index of the first element satisfying some predicate after or at some start index.
Finds index of the first element satisfying some predicate after or at some start index.
Note: may not terminate for infinite-sized collections.
the predicate used to test elements.
the start index
the index >= from of the first element of this immutable sequence that satisfies the predicate p,
or -1, if none exists.
Finds index of first element satisfying some predicate.
Finds index of first element satisfying some predicate.
Note: may not terminate for infinite-sized collections.
the predicate used to test elements.
the index of the first element of this immutable sequence that satisfies the predicate p,
or -1, if none exists.
Produces the range of all indices of this sequence.
Produces the range of all indices of this sequence.
a Range value from 0 to one less than the length of this immutable sequence.
Selects all elements except the last.
Selects all elements except the last.
a immutable sequence consisting of all elements of this immutable sequence except the last one.
if the immutable sequence is empty.
Iterates over the inits of this immutable sequence.
Iterates over the inits of this immutable sequence. The first value will be this
immutable sequence and the final one will be an empty immutable sequence, with the intervening
values the results of successive applications of init.
an iterator over all the inits of this immutable sequence
List(1,2,3).inits = Iterator(List(1,2,3), List(1,2), List(1), Nil)
[use case] Computes the multiset intersection between this immutable sequence and another sequence.
Computes the multiset intersection between this immutable sequence and another sequence.
Note: may not terminate for infinite-sized collections.
the sequence of elements to intersect with.
a new immutable sequence which contains all elements of this immutable sequence
which also appear in that.
If an element value x appears
n times in that, then the first n occurrences of x will be retained
in the result, but any following occurrences will be omitted.
Tests whether this immutable sequence contains given index.
Tests whether this immutable sequence contains given index.
The implementations of methods apply and isDefinedAt turn a Seq[A] into
a PartialFunction[Int, A].
the index to test
true if this immutable sequence contains an element at position idx, false otherwise.
Tests whether this immutable sequence is empty.
Tests whether this immutable sequence is empty.
true if the immutable sequence 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 sequence can be repeatedly traversed.
Tests whether this immutable sequence can be repeatedly traversed.
true
Selects the last element.
Selects the last element.
The last element of this immutable sequence.
If the immutable sequence is empty.
[use case] Finds index of last occurrence of some value in this immutable sequence before or at a given end index.
Finds index of last occurrence of some value in this immutable sequence before or at a given end index.
the element value to search for.
the end index.
the index <= end of the last element of this immutable sequence that is equal (as determined by ==)
to elem, or -1, if none exists.
[use case] Finds index of last occurrence of some value in this immutable sequence.
Finds index of last occurrence of some value in this immutable sequence.
Note: will not terminate for infinite-sized collections.
the element value to search for.
the index of the last element of this immutable sequence that is equal (as determined by ==)
to elem, or -1, if none exists.
Finds last index before or at a given end index where this immutable sequence contains a given sequence as a slice.
Finds last index before or at a given end index where this immutable sequence contains a given sequence as a slice.
the sequence to test
the end index
the last index <= end such that the elements of this immutable sequence starting at this index
match the elements of sequence that, or -1 of no such subsequence exists.
Finds last index where this immutable sequence contains a given sequence as a slice.
Finds last index where this immutable sequence contains a given sequence as a slice.
Note: will not terminate for infinite-sized collections.
the sequence to test
the last index such that the elements of this immutable sequence starting a this index
match the elements of sequence that, or -1 of no such subsequence exists.
Finds index of last element satisfying some predicate before or at given end index.
Finds index of last element satisfying some predicate before or at given end index.
the predicate used to test elements.
the index <= end of the last element of this immutable sequence that satisfies the predicate p,
or -1, if none exists.
Finds index of last element satisfying some predicate.
Finds index of last element satisfying some predicate.
Note: will not terminate for infinite-sized collections.
the predicate used to test elements.
the index of the last element of this immutable sequence that satisfies the predicate p,
or -1, if none exists.
Optionally selects the last element.
Optionally selects the last element.
the last element of this immutable sequence$ if it is nonempty,
None if it is empty.
Compares the length of this immutable sequence to a test value.
Compares the length of this immutable sequence to a test value.
the test value that gets compared with the length.
A value x where
x < 0 if this.length < len x == 0 if this.length == len x > 0 if this.length > len
The method as implemented here does not call length directly; its running time
is O(length min len) instead of O(length). The method should be overwritten
if computing length is cheap.
Turns this partial function into an plain function returning an Option result.
Turns this partial function into an plain function returning an Option result.
a function that takes an argument x to Some(this(x)) if this
is defined for x, and to None otherwise.
Function.unlift
[use case] Builds a new collection by applying a function to all elements of this immutable sequence.
Builds a new collection by applying a function to all elements of this immutable sequence.
the element type of the returned collection.
the function to apply to each element.
a new immutable sequence resulting from applying the given function
f to each element of this immutable sequence and collecting the results.
[use case] Finds the largest element.
Finds the largest element.
the largest element of this immutable sequence.
[use case] Finds the smallest element.
Finds the smallest element.
the smallest element of this immutable sequence
Displays all elements of this immutable sequence in a string.
Displays all elements of this immutable sequence in a string.
a string representation of this immutable sequence. In the resulting string
the string representations (w.r.t. the method toString)
of all elements of this immutable sequence follow each other without any
separator string.
Displays all elements of this immutable sequence in a string using a separator string.
Displays all elements of this immutable sequence in a string using a separator string.
the separator string.
a string representation of this immutable sequence. In the resulting string
the string representations (w.r.t. the method toString)
of all elements of this immutable sequence are separated by the string sep.
List(1, 2, 3).mkString("|") = "1|2|3"
Displays all elements of this immutable sequence in a string using start, end, and separator strings.
Displays all elements of this immutable sequence in a string using start, end, and separator strings.
the starting string.
the separator string.
the ending string.
a string representation of this immutable sequence. 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 sequence 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.Seq[A]
The builder that builds instances of type immutable.Seq[A]
Tests whether the immutable sequence is not empty.
Tests whether the immutable sequence is not empty.
true if the immutable sequence contains at least one element, false otherwise.
Wakes up a single thread that is waiting on the receiver object's monitor.
Wakes up a single thread that is waiting on the receiver object's monitor.
not specified by SLS as a member of AnyRef
Wakes up all threads that are waiting on the receiver object's monitor.
Wakes up all threads that are waiting on the receiver object's monitor.
not specified by SLS as a member of AnyRef
Composes this partial function with a fallback partial function which gets applied where this partial function is not defined.
Composes this partial function with a fallback partial function which gets applied where this partial function is not defined.
the argument type of the fallback function
the result type of the fallback function
the fallback function
a partial function which has as domain the union of the domains
of this partial function and that. The resulting partial function
takes x to this(x) where this is defined, and to that(x) where it is not.
[use case] A copy of this immutable sequence with an element value appended until a given target length is reached.
A copy of this immutable sequence with an element value appended until a given target length is reached.
the target length
the padding value
a new immutable sequence consisting of
all elements of this immutable sequence followed by the minimal number of occurrences of elem so
that the resulting immutable sequence has a length of at least len.
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 sequence in two immutable sequences according to a predicate.
Partitions this immutable sequence in two immutable sequences according to a predicate.
the predicate on which to partition.
a pair of immutable sequences: the first immutable sequence consists of all elements that
satisfy the predicate p and the second immutable sequence consists of all elements
that don't. The relative order of the elements in the resulting immutable sequences
is the same as in the original immutable sequence.
[use case] Produces a new immutable sequence where a slice of elements in this immutable sequence is replaced by another sequence.
Produces a new immutable sequence where a slice of elements in this immutable sequence is replaced by another sequence.
the index of the first replaced element
the number of elements to drop in the original immutable sequence
a new immutable sequence consisting of all elements of this immutable sequence
except that replaced elements starting from from are replaced
by patch.
Iterates over distinct permutations.
Iterates over distinct permutations.
An Iterator which traverses the distinct permutations of this immutable sequence.
"abb".permutations = Iterator(abb, bab, bba)
Returns the length of the longest prefix whose elements all satisfy some predicate.
Returns the length of the longest prefix whose elements all satisfy some predicate.
Note: may not terminate for infinite-sized collections.
the predicate used to test elements.
the length of the longest prefix of this immutable sequence
such that every element of the segment satisfies the predicate p.
[use case] Multiplies up the elements of this collection.
Multiplies up the elements of this collection.
the product of all elements in this immutable sequence 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 sequence and as result type of product.
Examples of such types are: Long, Float, Double, BigInt.
Reduces the elements of this immutable sequence using the specified associative binary operator.
Reduces the elements of this immutable sequence 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 sequence is nonempty.
if this immutable sequence is empty.
Applies a binary operator to all elements of this immutable sequence, going left to right.
Applies a binary operator to all elements of this immutable sequence, going left to right.
Note: will not terminate for infinite-sized collections.
the result type of the binary operator.
the binary operator.
the result of inserting op between consecutive elements of this immutable sequence,
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 sequence.
if this immutable sequence is empty.
Optionally applies a binary operator to all elements of this immutable sequence, going left to right.
Optionally applies a binary operator to all elements of this immutable sequence, going left to right.
Note: will not terminate for infinite-sized collections.
the result type of the binary operator.
the binary operator.
an option value containing the result of reduceLeft(op) is this immutable sequence is nonempty,
None otherwise.
Reduces the elements of this immutable sequence, if any, using the specified associative binary operator.
Reduces the elements of this immutable sequence, 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 sequence, going right to left.
Applies a binary operator to all elements of this immutable sequence, going right to left.
Note: will not terminate for infinite-sized collections.
the result type of the binary operator.
the binary operator.
the result of inserting op between consecutive elements of this immutable sequence,
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 sequence.
if this immutable sequence is empty.
Optionally applies a binary operator to all elements of this immutable sequence, going right to left.
Optionally applies a binary operator to all elements of this immutable sequence, going right to left.
Note: will not terminate for infinite-sized collections.
the result type of the binary operator.
the binary operator.
an option value containing the result of reduceRight(op) is this immutable sequence is nonempty,
None otherwise.
The collection of type immutable sequence underlying this TraversableLike object.
The collection of type immutable sequence underlying this TraversableLike object.
By default this is implemented as the TraversableLike object itself,
but this can be overridden.
Returns new immutable sequence wih elements in reversed order.
Returns new immutable sequence wih elements in reversed order.
Note: will not terminate for infinite-sized collections.
A new immutable sequence with all elements of this immutable sequence in reversed order.
An iterator yielding elements in reversed order.
An iterator yielding elements in reversed order.
Note: will not terminate for infinite-sized collections.
Note: xs.reverseIterator is the same as xs.reverse.iterator but might be more efficient.
an iterator yielding the elements of this immutable sequence in reversed order
[use case] Builds a new collection by applying a function to all elements of this immutable sequence and collecting the results in reversed order.
Builds a new collection by applying a function to all elements of this immutable sequence and collecting the results in reversed order.
Note: will not terminate for infinite-sized collections.
Note: xs.reverseMap(f) is the same as xs.reverse.map(f) but might be more efficient.
the element type of the returned collection.
the function to apply to each element.
a new immutable sequence resulting from applying the given function
f to each element of this immutable sequence and collecting the results in reversed order.
Composes this partial function with an action function which gets applied to results of this partial function.
Composes this partial function with an action function which gets applied to results of this partial function. The action function is invoked only for its side effects; its result is ignored.
Note that expression pf.runWith(action)(x) is equivalent to
if(pf isDefinedAt x) { action(pf(x)); true } else false
except that runWith is implemented via applyOrElse and thus potentially more efficient.
Using runWith avoids double evaluation of pattern matchers and guards for partial function literals.
the action function
a function which maps arguments x to isDefinedAt(x). The resulting function
runs action(this(x)) where this is defined.
2.10
applyOrElse.
[use case] Checks if the other iterable collection contains the same elements in the same order as this immutable sequence.
Checks if the other iterable collection contains the same elements in the same order as this immutable sequence.
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 sequence containing the prefix scan of the elements in this immutable sequence
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.
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 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.
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 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.
Computes length of longest segment whose elements all satisfy some predicate.
Computes length of longest segment whose elements all satisfy some predicate.
Note: may not terminate for infinite-sized collections.
the predicate used to test elements.
the index where the search starts.
the length of the longest segment of this immutable sequence starting from index from
such that every element of the segment satisfies the predicate p.
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 sequence, equivalent to length.
The size of this immutable sequence, equivalent to length.
Note: will not terminate for infinite-sized collections.
the number of elements in this immutable sequence.
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
a immutable sequence containing the elements greater than or equal to
index from extending up to (but not including) index until
of this immutable sequence.
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 sequences 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 sequences 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
Sorts this immutable.Seq according to the Ordering which results from transforming
an implicitly given Ordering with a transformation function.
Sorts this immutable.Seq according to the Ordering which results from transforming
an implicitly given Ordering with a transformation function.
the target type of the transformation f, and the type where
the ordering ord is defined.
the transformation function mapping elements
to some other domain B.
the ordering assumed on domain B.
a immutable sequence consisting of the elements of this immutable sequence
sorted according to the ordering where x < y if
ord.lt(f(x), f(y)).
val words = "The quick brown fox jumped over the lazy dog".split(' ') // this works because scala.Ordering will implicitly provide an Ordering[Tuple2[Int, Char]] words.sortBy(x => (x.length, x.head)) res0: Array[String] = Array(The, dog, fox, the, lazy, over, brown, quick, jumped)
Note: will not terminate for infinite-sized collections.
Sorts this immutable sequence according to a comparison function.
Sorts this immutable sequence according to a comparison function.
Note: will not terminate for infinite-sized collections.
The sort is stable. That is, elements that are equal (as determined by
lt) appear in the same order in the sorted sequence as in the original.
the comparison function which tests whether its first argument precedes its second argument in the desired ordering.
a immutable sequence consisting of the elements of this immutable sequence
sorted according to the comparison function lt.
List("Steve", "Tom", "John", "Bob").sortWith(_.compareTo(_) < 0) = List("Bob", "John", "Steve", "Tom")
Sorts this immutable sequence according to an Ordering.
Sorts this immutable sequence according to an Ordering.
The sort is stable. That is, elements that are equal (as determined by
lt) appear in the same order in the sorted sequence as in the original.
the ordering to be used to compare elements.
a immutable sequence consisting of the elements of this immutable sequence
sorted according to the ordering ord.
Splits this immutable sequence into a prefix/suffix pair according to a predicate.
Splits this immutable sequence 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.
a pair consisting of the longest prefix of this immutable sequence whose
elements all satisfy p, and the rest of this immutable sequence.
Splits this immutable sequence into two at a given position.
Splits this immutable sequence into two at a given position.
Note: c splitAt n is equivalent to (but possibly more efficient than)
(c take n, c drop n).
the position at which to split.
a pair of immutable sequences consisting of the first n
elements of this immutable sequence, and the other elements.
Tests whether this immutable sequence contains the given sequence at a given index.
Tests whether this immutable sequence contains the given sequence at a given index.
Note: If the both the receiver object this and the argument
that are infinite sequences this method may not terminate.
the sequence to test
the index where the sequence is searched.
true if the sequence that is contained in this immutable sequence at
index offset, otherwise false.
Tests whether this immutable sequence starts with the given sequence.
Tests whether this immutable sequence starts with the given sequence.
the sequence to test
true if this collection has that as a prefix, false otherwise.
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 sequence. By default the string prefix is the
simple name of the collection class immutable sequence.
[use case] Sums up the elements of this collection.
Sums up the elements of this collection.
the sum of all elements in this immutable sequence 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 sequence 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.
a immutable sequence consisting of all elements of this immutable sequence except the first one.
if the immutable sequence is empty.
Iterates over the tails of this immutable sequence.
Iterates over the tails of this immutable sequence. The first value will be this
immutable sequence and the final one will be an empty immutable sequence, with the intervening
values the results of successive applications of tail.
an iterator over all the tails of this immutable sequence
List(1,2,3).tails = Iterator(List(1,2,3), List(2,3), List(3), Nil)
Selects first n elements.
Selects first n elements.
the number of elements to take from this immutable sequence.
a immutable sequence consisting only of the first n elements of this immutable sequence,
or else the whole immutable sequence, if it has less than n elements.
Selects last n elements.
Selects last n elements.
the number of elements to take
a immutable sequence consisting only of the last n elements of this immutable sequence, or else the
whole immutable sequence, 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.
the longest prefix of this immutable sequence whose elements all satisfy
the predicate p.
The underlying collection seen as an instance of immutable.Seq
The underlying collection seen as an instance of immutable.Seq
[use case] Converts this immutable sequence into another by copying all elements.
Converts this immutable sequence 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 sequence.
[use case] Converts this immutable sequence to an array.
Converts this immutable sequence to an array.
Note: will not terminate for infinite-sized collections.
an array containing all elements of this immutable sequence.
An ClassTag must be available for the element type of this immutable sequence.
Converts this immutable sequence to a mutable buffer.
Converts this immutable sequence to a mutable buffer.
Note: will not terminate for infinite-sized collections.
a buffer containing all elements of this immutable sequence.
A conversion from collections of type Repr to immutable.Seq
A conversion from collections of type Repr to immutable.Seq
Converts this immutable sequence to an indexed sequence.
Converts this immutable sequence to an indexed sequence.
Note: will not terminate for infinite-sized collections.
an indexed sequence containing all elements of this immutable sequence.
Converts this immutable sequence to an iterable collection.
Converts this immutable sequence 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 sequence.
Returns an Iterator over the elements in this immutable sequence.
Returns an Iterator over the elements in this immutable sequence. 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 sequence.
Converts this immutable sequence to a list.
Converts this immutable sequence to a list.
Note: will not terminate for infinite-sized collections.
a list containing all elements of this immutable sequence.
[use case] Converts this immutable sequence to a map.
Converts this immutable sequence 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 sequence.
Converts this immutable sequence to a sequence.
Converts this immutable sequence to a sequence.
Note: will not terminate for infinite-sized collections.
Overridden for efficiency.
a sequence containing all elements of this immutable sequence.
Converts this immutable sequence to a set.
Converts this immutable sequence to a set.
Note: will not terminate for infinite-sized collections.
a set containing all elements of this immutable sequence.
Converts this immutable sequence to a stream.
Converts this immutable sequence to a stream.
Note: will not terminate for infinite-sized collections.
a stream containing all elements of this immutable sequence.
Converts this immutable sequence to a string.
Converts this immutable sequence to a string.
a string representation of this collection. By default this
string consists of the stringPrefix of this immutable sequence, followed
by all elements separated by commas and enclosed in parentheses.
Converts this immutable sequence to an unspecified Traversable.
Converts this immutable sequence 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 sequence.
Converts this immutable sequence to a Vector.
Converts this immutable sequence to a Vector.
Note: will not terminate for infinite-sized collections.
a vector containing all elements of this immutable sequence.
Transposes this immutable sequence of traversable collections into a immutable sequence of immutable sequences.
Transposes this immutable sequence of traversable collections into a immutable sequence of immutable sequences.
the type of the elements of each traversable collection.
an implicit conversion which asserts that the
element type of this immutable sequence is a Traversable.
a two-dimensional immutable sequence of immutable sequences which has as nth row the nth column of this immutable sequence.
(Changed in version 2.9.0) transpose throws an IllegalArgumentException if collections are not uniformly sized.
if all collections in this immutable sequence are not of the same size.
[use case] Produces a new sequence which contains all elements of this immutable sequence and also all elements of a given sequence.
Produces a new sequence which contains all elements of this immutable sequence and also all elements of
a given sequence. xs union ys is equivalent to xs ++ ys.
Another way to express this
is that xs union ys computes the order-presevring multi-set union of xs and ys.
union is hence a counter-part of diff and intersect which also work on multi-sets.
Note: will not terminate for infinite-sized collections.
the sequence to add.
a new immutable sequence which contains all elements of this immutable sequence
followed by all elements of that.
Converts this immutable sequence of pairs into two collections of the first and second half of each pair.
Converts this immutable sequence 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 sequence is a pair.
a pair immutable sequences, containing the first, respectively second half of each element pair of this immutable sequence.
Converts this immutable sequence of triples into three collections of the first, second, and third element of each triple.
Converts this immutable sequence 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 sequence is a triple.
a triple immutable sequences, containing the first, second, respectively third member of each element triple of this immutable sequence.
[use case] A copy of this immutable sequence with one single replaced element.
A copy of this immutable sequence with one single replaced element.
the position of the replacement
the replacing element
a copy of this immutable sequence with the element at position index replaced by elem.
Creates a non-strict view of a slice of this immutable sequence.
Creates a non-strict view of a slice of this immutable sequence.
Note: the difference between view and slice is that view produces
a view of the current immutable sequence, whereas slice produces a new immutable sequence.
Note: view(from, to) is equivalent to view.slice(from, to)
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 sequence, starting at index from
and extending up to (but not including) index until.
Creates a non-strict view of this immutable sequence.
Creates a non-strict view of this immutable sequence.
a non-strict view of this immutable sequence.
Creates a non-strict filter of this immutable sequence.
Creates a non-strict filter of this immutable sequence.
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.
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 sequence
which satisfy the predicate p.
[use case] Returns a immutable sequence formed from this immutable sequence and another iterable collection by combining corresponding elements in pairs.
Returns a immutable sequence formed from this immutable sequence and another iterable collection by combining corresponding elements in pairs. If one of the two collections is longer than the other, its remaining elements are ignored.
the type of the second half of the returned pairs
The iterable providing the second half of each result pair
a new immutable sequence containing pairs consisting of
corresponding elements of this immutable sequence and that. The length
of the returned collection is the minimum of the lengths of this immutable sequence and that.
[use case] Returns a immutable sequence formed from this immutable sequence and another iterable collection by combining corresponding elements in pairs.
Returns a immutable sequence formed from this immutable sequence and another iterable collection by combining corresponding elements in pairs. If one of the two collections is shorter than the other, placeholder elements are used to extend the shorter collection to the length of the longer.
the 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 sequence is shorter than that.
the element to be used to fill up the result if that is shorter than this immutable sequence.
a new immutable sequence containing pairs consisting of
corresponding elements of this immutable sequence and that. The length
of the returned collection is the maximum of the lengths of this immutable sequence and that.
If this immutable sequence is shorter than that, thisElem values are used to pad the result.
If that is shorter than this immutable sequence, thatElem values are used to pad the result.
[use case] Zips this immutable sequence with its indices.
Zips this immutable sequence with its indices.
A new immutable sequence containing pairs consisting of all elements of this
immutable sequence paired with their index. Indices start at 0.
List("a", "b", "c").zipWithIndex = List(("a", 0), ("b", 1), ("c", 2))
(seq: MonadOps[A]).filter(p)
(seq: MonadOps[A]).flatMap(f)
(seq: MonadOps[A]).map(f)
(seq: StringAdd).self
(seq: StringFormat).self
(seq: 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
(seq: ArrowAssoc[Seq[A]]).x
(Since version 2.10.0) Use leftOfArrow instead
(seq: Ensuring[Seq[A]]).x
(Since version 2.10.0) Use resultOfEnsuring instead
A subtrait of
collection.Seqwhich represents sequences that are guaranteed immutable.Sequences are special cases of iterable collections of class
Iterable. Unlike iterables, sequences always have a defined order of elements. Sequences provide a methodapplyfor indexing. Indices range from0up to thelengthof a sequence. Sequences support a number of methods to find occurrences of elements or subsequences, includingsegmentLength,prefixLength,indexWhere,indexOf,lastIndexWhere,lastIndexOf,startsWith,endsWith,indexOfSlice.Another way to see a sequence is as a
PartialFunctionfromIntvalues to the element type of the sequence. TheisDefinedAtmethod of a sequence returnstruefor the interval from0untillength.Sequences can be accessed in reverse order of their elements, using methods
reverseandreverseIterator.Sequences have two principal subtraits,
IndexedSeqandLinearSeq, which give different guarantees for performance. AnIndexedSeqprovides fast random-access of elements and a fastlengthoperation. ALinearSeqprovides fast access only to the first element viahead, but also has a fasttailoperation.