Class scala.collection.SeqView.Id
class Id[+A] extends AbstractSeqView[A]
Instance Constructors
new Id(underlying: SomeSeqOps[A])
Value Members
final def !=(arg0: Any): Boolean
Test two objects for inequality.
- returns
true
if !(this == that), false otherwise.
- Definition Classes
- AnyRef → Any
final def ##(): Int
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
.
- returns
a hash value consistent with ==
- Definition Classes
- AnyRef → Any
def +(other: String): String
- Implicit
- This member is added by an implicit conversion from Id[A] toany2stringadd[Id[A]] performed by method any2stringadd in scala.Predef.
- Definition Classes
- any2stringadd
final def ++[B >: A](suffix: IterableOnce[B]): View[B]
Alias for concat
- Definition Classes
- IterableOps
- Annotations
- @inline()
final def ++:[B >: A](prefix: IterableOnce[B]): View[B]
Alias for prependedAll
- Definition Classes
- SeqOps → IterableOps
- Annotations
- @inline()
final def +:[B >: A](elem: B): View[B]
Alias for prepended
.
Note that :-ending operators are right associative (see example). A mnemonic for +:
vs. :+
is: the COLon goes on the COLlection side.
def ->[B](y: B): (Id[A], B)
- Implicit
- This member is added by an implicit conversion from Id[A] toArrowAssoc[Id[A]] performed by method ArrowAssoc in scala.Predef.
- Definition Classes
- ArrowAssoc
- Annotations
- @inline()
final def :+[B >: A](elem: B): View[B]
Alias for appended
Note that :-ending operators are right associative (see example). A mnemonic for +:
vs. :+
is: the COLon goes on the COLlection side.
final def :++[B >: A](suffix: IterableOnce[B]): View[B]
final def ==(arg0: Any): Boolean
The expression x == that
is equivalent to if (x eq null) that eq null else x.equals(that)
.
- returns
true
if the receiver object is equivalent to the argument;false
otherwise.
- Definition Classes
- AnyRef → Any
final def addString(b: mutable.StringBuilder): mutable.StringBuilder
Appends all elements of this collection to a string builder. The written text consists of the string representations (w.r.t. the method toString
) of all elements of this collection without any separator string.
Example:
scala> val a = List(1,2,3,4) a: List[Int] = List(1, 2, 3, 4) scala> val b = new StringBuilder() b: StringBuilder = scala> val h = a.addString(b) h: StringBuilder = 1234
- b
the string builder to which elements are appended.
- returns
the string builder
b
to which elements were appended.
- Definition Classes
- IterableOnceOps
- Annotations
- @inline()
final def addString(b: mutable.StringBuilder, sep: String): mutable.StringBuilder
Appends all elements of this 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 collection, separated by the string sep
.
Example:
scala> val a = List(1,2,3,4) a: List[Int] = List(1, 2, 3, 4) scala> val b = new StringBuilder() b: StringBuilder = scala> a.addString(b, ", ") res0: StringBuilder = 1, 2, 3, 4
- b
the string builder to which elements are appended.
- sep
the separator string.
- returns
the string builder
b
to which elements were appended.
- Definition Classes
- IterableOnceOps
- Annotations
- @inline()
def addString(b: mutable.StringBuilder, start: String, sep: String, end: String): mutable.StringBuilder
Appends all elements of this 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 collection are separated by the string sep
.
Example:
scala> val a = List(1,2,3,4) a: List[Int] = List(1, 2, 3, 4) scala> val b = new StringBuilder() b: StringBuilder = scala> a.addString(b , "List(" , ", " , ")") res5: StringBuilder = List(1, 2, 3, 4)
- b
the string builder to which elements are appended.
- start
the starting string.
- sep
the separator string.
- end
the ending string.
- returns
the string builder
b
to which elements were appended.
- Definition Classes
- IterableOnceOps
def appended[B >: A](elem: B): SeqView[B]
A copy of this view with an element appended.
Note: will not terminate for infinite-sized collections.
Example:
scala> val a = List(1) a: List[Int] = List(1) scala> val b = a :+ 2 b: List[Int] = List(1, 2) scala> println(a) List(1)
- B
the element type of the returned view.
- elem
the appended element
- returns
a new view consisting of all elements of this view followed by
value
.
def appendedAll[B >: A](suffix: SomeSeqOps[B]): SeqView[B]
- Definition Classes
- SeqView
def appendedAll[B >: A](suffix: IterableOnce[B]): View[B]
Returns a new sequence containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the sequence is the most specific superclass encompassing the element types of the two operands.
- B
the element type of the returned collection.
- suffix
the iterable to append.
- returns
a new collection of type
CC[B]
which contains all elements of this sequence followed by all elements ofsuffix
.
- Definition Classes
- SeqOps
def apply(idx: Int): A
Get the element at the specified index. This operation is provided for convenience in Seq
. It should not be assumed to be efficient unless you have an IndexedSeq
.
final def asInstanceOf[T0]: 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.
- returns
the receiver object.
- Definition Classes
- Any
- Exceptions thrown
ClassCastException
if the receiver object is not an instance of the erasure of typeT0
.
def className: String
Defines the prefix of this object's toString
representation.
It is recommended to return the name of the concrete collection type, but not implementation subclasses. For example, for ListMap
this method should return "ListMap"
, not "Map"
(the supertype) or "Node"
(an implementation subclass).
The default implementation returns "Iterable". It is overridden for the basic collection kinds "Seq", "IndexedSeq", "LinearSeq", "Buffer", "Set", "Map", "SortedSet", "SortedMap" and "View".
- returns
a string representation which starts the result of
toString
applied to this iterable collection. By default the string prefix is the simple name of the collection class iterable collection.
- Attributes
- protected[this]
- Definition Classes
- Iterable
def clone(): AnyRef
Create a copy of the receiver object.
The default implementation of the clone
method is platform dependent.
- returns
a copy of the receiver object.
final def coll: Id.this.type
- returns
This collection as a
C
.
- Attributes
- protected
- Definition Classes
- Iterable → IterableOps
def collect[B](pf: PartialFunction[A, B]): View[B]
Builds a new iterable collection by applying a partial function to all elements of this iterable collection on which the function is defined.
- B
the element type of the returned iterable collection.
- pf
the partial function which filters and maps the iterable collection.
- returns
a new 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.
- Definition Classes
- IterableOps → IterableOnceOps
- Note
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.
def collectFirst[B](pf: PartialFunction[A, B]): Option[B]
Finds the first element of the 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.
- pf
the partial function
- returns
an option value containing pf applied to the first value for which it is defined, or
None
if none exists.
- Definition Classes
- IterableOnceOps
Seq("a", 1, 5L).collectFirst({ case x: Int => x*10 }) = Some(10)
def combinations(n: Int): Iterator[View[A]]
Iterates over combinations. A _combination_ of length n
is a subsequence of the original sequence, with the elements taken in order. Thus, "xy"
and "yy"
are both length-2 combinations of "xyy"
, but "yx"
is not. If there is more than one way to generate the same subsequence, only one will be returned.
For example, "xyyy"
has three different ways to generate "xy"
depending on whether the first, second, or third "y"
is selected. However, since all are identical, only one will be chosen. Which of the three will be taken is an implementation detail that is not defined.
Note: Even when applied to a view or a lazy collection it will always force the elements.
- returns
An Iterator which traverses the possible n-element combinations of this sequence.
- Definition Classes
- SeqOps
"abbbc".combinations(2) = Iterator(ab, ac, bb, bc)
def concat[B >: A](suffix: SomeSeqOps[B]): SeqView[B]
- Definition Classes
- SeqView
final def concat[B >: A](suffix: IterableOnce[B]): View[B]
Returns a new sequence containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the sequence is the most specific superclass encompassing the element types of the two operands.
- B
the element type of the returned collection.
- suffix
the traversable to append.
- returns
a new sequence which contains all elements of this sequence followed by all elements of
suffix
.
- Definition Classes
- SeqOps → IterableOps
- Annotations
- @inline()
def contains[A1 >: A](elem: A1): Boolean
Tests whether this sequence contains a given value as an element.
Note: may not terminate for infinite-sized collections.
- elem
the element to test.
- returns
true
if this sequence has an element that is equal (as determined by==
) toelem
,false
otherwise.
- Definition Classes
- SeqOps
def containsSlice[B](that: Seq[B]): Boolean
Tests whether this sequence contains a given sequence as a slice.
Note: may not terminate for infinite-sized collections.
- that
the sequence to test
- returns
true
if this sequence contains a slice with the same elements asthat
, otherwisefalse
.
- Definition Classes
- SeqOps
def copyToArray[B >: A](xs: Array[B], start: Int, len: Int): Int
Copy elements to an array, returning the number of elements written.
Fills the given array xs
starting at index start
with at most len
elements of this collection.
Copying will stop once either all the elements of this collection have been copied, or the end of the array is reached, or len
elements have been copied.
- B
the type of the elements of the array.
- xs
the array to fill.
- start
the starting index of xs.
- len
the maximal number of elements to copy.
- returns
the number of elements written to the array
- Definition Classes
- IterableOnceOps
- Note
Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change. Note: will not terminate for infinite-sized collections.
def copyToArray[B >: A](xs: Array[B], start: Int): Int
Copy elements to an array, returning the number of elements written.
Fills the given array xs
starting at index start
with values of this collection.
Copying will stop once either all the elements of this collection have been copied, or the end of the array is reached.
- B
the type of the elements of the array.
- xs
the array to fill.
- start
the starting index of xs.
- returns
the number of elements written to the array Note: will not terminate for infinite-sized collections.
- Definition Classes
- IterableOnceOps
def copyToArray[B >: A](xs: Array[B]): Int
Copy elements to an array, returning the number of elements written.
Fills the given array xs
starting at index start
with values of this collection.
Copying will stop once either all the elements of this collection have been copied, or the end of the array is reached.
- B
the type of the elements of the array.
- xs
the array to fill.
- returns
the number of elements written to the array Note: will not terminate for infinite-sized collections.
- Definition Classes
- IterableOnceOps
def corresponds[B](that: Seq[B])(p: (A, B) => Boolean): Boolean
Tests whether every element of this sequence relates to the corresponding element of another sequence by satisfying a test predicate.
- B
the type of the elements of
that
- that
the other sequence
- p
the test predicate, which relates elements from both sequences
- returns
true
if both sequences have the same length andp(x, y)
istrue
for all corresponding elementsx
of this sequence andy
ofthat
, otherwisefalse
.
- Definition Classes
- SeqOps
def corresponds[B](that: IterableOnce[B])(p: (A, B) => Boolean): Boolean
Tests whether every element of this collection's iterator relates to the corresponding element of another collection by satisfying a test predicate.
- B
the type of the elements of
that
- that
the other collection
- p
the test predicate, which relates elements from both collections
- returns
true
if both collections have the same length andp(x, y)
istrue
for all corresponding elementsx
of this iterator andy
ofthat
, otherwisefalse
- Definition Classes
- IterableOnceOps
def count(p: (A) => Boolean): Int
Counts the number of elements in the collection which satisfy a predicate.
- p
the predicate used to test elements.
- returns
the number of elements satisfying the predicate
p
.
- Definition Classes
- IterableOnceOps
def diff[B >: A](that: Seq[B]): View[A]
Computes the multiset difference between this sequence and another sequence.
- that
the sequence of elements to remove
- returns
a new sequence which contains all elements of this sequence except some of occurrences of elements that also appear in
that
. If an element valuex
appears n times inthat
, then the first n occurrences ofx
will not form part of the result, but any following occurrences will.
- Definition Classes
- SeqOps
def distinct: View[A]
Selects all the elements of this sequence ignoring the duplicates.
- returns
a new sequence consisting of all the elements of this sequence without duplicates.
- Definition Classes
- SeqOps
def distinctBy[B](f: (A) => B): View[A]
Selects all the elements of this sequence ignoring the duplicates as determined by ==
after applying the transforming function f
.
- B
the type of the elements after being transformed by
f
- f
The transforming function whose result is used to determine the uniqueness of each element
- returns
a new sequence consisting of all the elements of this sequence without duplicates.
- Definition Classes
- SeqOps
def drop(n: Int): SeqView[A]
Selects all elements except first n ones.
- n
the number of elements to drop from this view.
- returns
a view consisting of all elements of this view except the first
n
ones, or else the empty view, if this view has less thann
elements. Ifn
is negative, don't drop any elements.
- Definition Classes
- SeqView → IterableOps → IterableOnceOps
- Note
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.
def dropRight(n: Int): SeqView[A]
Selects all elements except last n ones.
- n
the number of elements to drop from this view.
- returns
a view consisting of all elements of this view except the last
n
ones, or else the empty view, if this view has less thann
elements. Ifn
is negative, don't drop any elements.
- Definition Classes
- SeqView → IterableOps
def dropWhile(p: (A) => Boolean): View[A]
Drops longest prefix of elements that satisfy a predicate.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- p
The predicate used to test elements.
- returns
the longest suffix of this iterable collection whose first element does not satisfy the predicate
p
.
- Definition Classes
- IterableOps → IterableOnceOps
- Note
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.
def empty: View[A]
The empty iterable of the same type as this iterable
- returns
an empty iterable of type
C
.
- Definition Classes
- View → IterableFactoryDefaults → IterableOps
def endsWith[B >: A](that: Iterable[B]): Boolean
Tests whether this sequence ends with the given sequence.
Note: will not terminate for infinite-sized collections.
- that
the sequence to test
- returns
true
if this sequence hasthat
as a suffix,false
otherwise.
- Definition Classes
- SeqOps
def ensuring(cond: (Id[A]) => Boolean, msg: => Any): Id[A]
- Implicit
- This member is added by an implicit conversion from Id[A] toEnsuring[Id[A]] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
def ensuring(cond: (Id[A]) => Boolean): Id[A]
- Implicit
- This member is added by an implicit conversion from Id[A] toEnsuring[Id[A]] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
def ensuring(cond: Boolean, msg: => Any): Id[A]
- Implicit
- This member is added by an implicit conversion from Id[A] toEnsuring[Id[A]] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
def ensuring(cond: Boolean): Id[A]
- Implicit
- This member is added by an implicit conversion from Id[A] toEnsuring[Id[A]] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
final def eq(arg0: AnyRef): Boolean
Tests whether the argument (that
) 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:
-
It is consistent: for any non-null instances
x
and y
of type AnyRef
, multiple invocations of x.eq(y)
consistently returns true
or consistently returns false
.For any non-null instance 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
).
- returns
true
if the argument is a reference to the receiver object;false
otherwise.
- Definition Classes
- AnyRef
def equals(arg0: AnyRef): Boolean
The equality method for reference types. Default implementation delegates to eq
.
See also equals
in scala.Any.
- returns
true
if the receiver object is equivalent to the argument;false
otherwise.
- Definition Classes
- AnyRef → Any
def exists(p: (A) => Boolean): Boolean
Tests whether a predicate holds for at least one element of this collection.
Note: may not terminate for infinite-sized collections.
- p
the predicate used to test elements.
- returns
true
if the given predicatep
is satisfied by at least one element of this collection, otherwisefalse
- Definition Classes
- IterableOnceOps
def filter(pred: (A) => Boolean): View[A]
Selects all elements of this iterable collection which satisfy a predicate.
- returns
a new iterator consisting of all elements of this iterable collection that satisfy the given predicate
p
. The order of the elements is preserved.
- Definition Classes
- IterableOps → IterableOnceOps
def filterNot(pred: (A) => Boolean): View[A]
Selects all elements of this iterable collection which do not satisfy a predicate.
- pred
the predicate used to test elements.
- returns
a new iterable collection consisting of all elements of this iterable collection that do not satisfy the given predicate
pred
. Their order may not be preserved.
- Definition Classes
- IterableOps → IterableOnceOps
def finalize(): Unit
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.
def find(p: (A) => Boolean): Option[A]
Finds the first element of the 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.
- p
the predicate used to test elements.
- returns
an option value containing the first element in the collection that satisfies
p
, orNone
if none exists.
- Definition Classes
- IterableOnceOps
def findLast(p: (A) => Boolean): Option[A]
Finds the last element of the sequence satisfying a predicate, if any.
Note: will not terminate for infinite-sized collections.
- p
the predicate used to test elements.
- returns
an option value containing the last element in the sequence that satisfies
p
, orNone
if none exists.
- Definition Classes
- SeqOps
def flatMap[B](f: (A) => IterableOnce[B]): View[B]
Builds a new iterable collection by applying a function to all elements of this 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 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: String) => word.toSeq) // xs will be an Iterable[Int] val xs = Map("a" -> List(11,111), "b" -> List(22,222)).flatMap(_._2) // ys will be a Map[Int, Int] val ys = Map("a" -> List(1 -> 11,1 -> 111), "b" -> List(2 -> 22,2 -> 222)).flatMap(_._2)
- B
the element type of the returned collection.
- f
the function to apply to each element.
- returns
a new iterable collection resulting from applying the given collection-valued function
f
to each element of this iterable collection and concatenating the results.
- Definition Classes
- IterableOps → IterableOnceOps
- Note
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.
def flatten[B](implicit asIterable: (A) => IterableOnce[B]): View[B]
Converts this iterable collection of traversable collections into a iterable collection formed by the elements of these traversable collections.
The resulting collection's type will be guided by the type of iterable collection. For example:
val xs = List( Set(1, 2, 3), Set(1, 2, 3) ).flatten // xs == List(1, 2, 3, 1, 2, 3) val ys = Set( List(1, 2, 3), List(3, 2, 1) ).flatten // ys == Set(1, 2, 3)
- B
the type of the elements of each traversable collection.
- asIterable
an implicit conversion which asserts that the element type of this iterable collection is a
GenTraversable
.- returns
a new iterable collection resulting from concatenating all element iterable collections.
- Definition Classes
- IterableOps → IterableOnceOps
- Note
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.
def fold[A1 >: A](z: A1)(op: (A1, A1) => A1): A1
Folds the elements of this collection using the specified associative binary operator. The default implementation in IterableOnce
is equivalent to foldLeft
but may be overridden for more efficient traversal orders.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
Note: will not terminate for infinite-sized collections.
- A1
a type parameter for the binary operator, a supertype of
A
.- z
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).- op
a binary operator that must be associative.
- returns
the result of applying the fold operator
op
between all the elements andz
, orz
if this collection is empty.
- Definition Classes
- IterableOnceOps
def foldLeft[B](z: B)(op: (B, A) => B): B
Applies a binary operator to a start value and all elements of this 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.
- B
the result type of the binary operator.
- z
the start value.
- op
the binary operator.
- returns
-
the result of inserting
op
between consecutive elements of this collection, going left to right with the start valuez
on the left:op(...op(z, x_1), x_2, ..., x_n)
where
x1, ..., xn
are the elements of this collection. Returnsz
if this collection is empty.
- Definition Classes
- IterableOnceOps
def foldRight[B](z: B)(op: (A, B) => B): B
Applies a binary operator to all elements of this 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.
- B
the result type of the binary operator.
- z
the start value.
- op
the binary operator.
- returns
-
the result of inserting
op
between consecutive elements of this collection, going right to left with the start valuez
on the right:op(x_1, op(x_2, ... op(x_n, z)...))
where
x1, ..., xn
are the elements of this collection. Returnsz
if this collection is empty.
- Definition Classes
- IterableOnceOps
def forall(p: (A) => Boolean): Boolean
Tests whether a predicate holds for all elements of this collection.
Note: may not terminate for infinite-sized collections.
- p
the predicate used to test elements.
- returns
true
if this collection is empty or the given predicatep
holds for all elements of this collection, otherwisefalse
.
- Definition Classes
- IterableOnceOps
def foreach[U](f: (A) => U): Unit
Apply f
to each element for its side effects Note: [U] parameter needed to help scalac's type inference.
- Definition Classes
- IterableOnceOps
def formatted(fmtstr: String): String
Returns string formatted according to given format
string. Format strings are as for String.format
(@see java.lang.String.format).
- Implicit
- This member is added by an implicit conversion from Id[A] toStringFormat[Id[A]] performed by method StringFormat in scala.Predef.
- Definition Classes
- StringFormat
- Annotations
- @inline()
def fromSpecific(coll: IterableOnce[A]): View[A]
Defines how to turn a given Iterable[A]
into a collection of type C
.
This process can be done in a strict way or a non-strict way (ie. without evaluating the elements of the resulting collections). In other words, this methods defines the evaluation model of the collection.
- Attributes
- protected
- Definition Classes
- IterableFactoryDefaults → IterableOps
- Note
-
When implementing a custom collection type and refining
,C
to the new type, this method needs to be overridden (the compiler will issue an error otherwise). In the common case whereC =:= CC[A]
, this can be done by mixing in the IterableFactoryDefaults trait, which implements the method using iterableFactory.As witnessed by the
@uncheckedVariance
annotation, using this method might be unsound. However, as long as it is called with anIterable[A]
obtained fromthis
collection (as it is the case in the implementations of operations where we use aView[A]
), it is safe.
final def getClass(): Class[_ <: AnyRef]
Returns the runtime class representation of the object.
- returns
a class object corresponding to the runtime type of the receiver.
def groupBy[K](f: (A) => K): immutable.Map[K, View[A]]
Partitions this iterable collection into a map of iterable collections according to some discriminator function.
Note: Even when applied to a view or a lazy collection it will always force the elements.
- K
the type of keys returned by the discriminator function.
- f
the discriminator function.
- returns
-
A map from keys to iterable collections such that the following invariant holds:
(xs groupBy f)(k) = xs filter (x => f(x) == k)
That is, every key
k
is bound to a iterable collection of those elementsx
for whichf(x)
equalsk
.
- Definition Classes
- IterableOps
def groupMap[K, B](key: (A) => K)(f: (A) => B): immutable.Map[K, View[B]]
Partitions this iterable collection into a map of iterable collections according to a discriminator function key
. Each element in a group is transformed into a value of type B
using the value
function.
It is equivalent to groupBy(key).mapValues(_.map(f))
, but more efficient.
case class User(name: String, age: Int) def namesByAge(users: Seq[User]): Map[Int, Seq[String]] = users.groupMap(_.age)(_.name)
Note: Even when applied to a view or a lazy collection it will always force the elements.
- K
the type of keys returned by the discriminator function
- B
the type of values returned by the transformation function
- key
the discriminator function
- f
the element transformation function
- Definition Classes
- IterableOps
def groupMapReduce[K, B](key: (A) => K)(f: (A) => B)(reduce: (B, B) => B): immutable.Map[K, B]
Partitions this iterable collection into a map according to a discriminator function key
. All the values that have the same discriminator are then transformed by the value
function and then reduced into a single value with the reduce
function.
It is equivalent to groupBy(key).mapValues(_.map(f).reduce(reduce))
, but more efficient.
def occurrences[A](as: Seq[A]): Map[A, Int] = as.groupMapReduce(identity)(_ => 1)(_ + _)
Note: Even when applied to a view or a lazy collection it will always force the elements.
- Definition Classes
- IterableOps
def grouped(size: Int): Iterator[View[A]]
Partitions elements in fixed size iterable collections.
- size
the number of elements per group
- returns
An iterator producing iterable collections of size
size
, except the last will be less than sizesize
if the elements don't divide evenly.
- Definition Classes
- IterableOps
- See also
scala.collection.Iterator, method
grouped
def hashCode(): Int
The hashCode method for reference types. See hashCode in scala.Any.
- returns
the hash code value for this object.
def head: A
Selects the first element of this iterable collection.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- returns
the first element of this iterable collection.
- Definition Classes
- IterableOps
- Exceptions thrown
NoSuchElementException
if the iterable collection is empty.
def headOption: Option[A]
Optionally selects the first element.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- returns
the first element of this iterable collection if it is nonempty,
None
if it is empty.
- Definition Classes
- IterableOps
def indexOf[B >: A](elem: B): Int
Finds index of first occurrence of some value in this sequence.
- B
the type of the element
elem
.- elem
the element value to search for.
- returns
the index
>= 0
of the first element of this sequence that is equal (as determined by==
) toelem
, or-1
, if none exists.
- Definition Classes
- SeqOps
- Annotations
- @deprecatedOverriding("Override indexOf(elem, from) instead - indexOf(elem) calls indexOf(elem, 0)", "2.13.0")
def indexOf[B >: A](elem: B, from: Int): Int
Finds index of first occurrence of some value in this sequence after or at some start index.
- B
the type of the element
elem
.- elem
the element value to search for.
- from
the start index
- returns
the index
>= from
of the first element of this sequence that is equal (as determined by==
) toelem
, or-1
, if none exists.
- Definition Classes
- SeqOps
def indexOfSlice[B >: A](that: Seq[B]): Int
Finds first index where this sequence contains a given sequence as a slice.
Note: may not terminate for infinite-sized collections.
- that
the sequence to test
- returns
the first index
>= 0
such that the elements of this sequence starting at this index match the elements of sequencethat
, or-1
of no such subsequence exists.
- Definition Classes
- SeqOps
- Annotations
- @deprecatedOverriding("Override indexOfSlice(that, from) instead - indexOfSlice(that) calls indexOfSlice(that, 0)", "2.13.0")
def indexOfSlice[B >: A](that: Seq[B], from: Int): Int
Finds first index after or at a start index where this sequence contains a given sequence as a slice.
Note: may not terminate for infinite-sized collections.
- that
the sequence to test
- from
the start index
- returns
the first index
>= from
such that the elements of this sequence starting at this index match the elements of sequencethat
, or-1
of no such subsequence exists.
- Definition Classes
- SeqOps
def indexWhere(p: (A) => Boolean): Int
Finds index of the first element satisfying some predicate.
Note: may not terminate for infinite-sized collections.
- p
the predicate used to test elements.
- returns
the index
>= 0
of the first element of this sequence that satisfies the predicatep
, or-1
, if none exists.
- Definition Classes
- SeqOps
- Annotations
- @deprecatedOverriding("Override indexWhere(p, from) instead - indexWhere(p) calls indexWhere(p, 0)", "2.13.0")
def indexWhere(p: (A) => Boolean, from: Int): Int
Finds index of the first element satisfying some predicate after or at some start index.
Note: may not terminate for infinite-sized collections.
- p
the predicate used to test elements.
- from
the start index
- returns
the index
>= from
of the first element of this sequence that satisfies the predicatep
, or-1
, if none exists.
- Definition Classes
- SeqOps
def indices: immutable.Range
Produces the range of all indices of this sequence.
Note: Even when applied to a view or a lazy collection it will always force the elements.
- returns
a
Range
value from0
to one less than the length of this sequence.
- Definition Classes
- SeqOps
def init: View[A]
The initial part of the collection without its last element.
Note: Even when applied to a view or a lazy collection it will always force the elements.
- Definition Classes
- IterableOps
def inits: Iterator[View[A]]
Iterates over the inits of this iterable collection. The first value will be this iterable collection and the final one will be an empty iterable collection, with the intervening values the results of successive applications of init
.
Note: Even when applied to a view or a lazy collection it will always force the elements.
- returns
an iterator over all the inits of this iterable collection
- Definition Classes
- IterableOps
List(1,2,3).inits = Iterator(List(1,2,3), List(1,2), List(1), Nil)
def intersect[B >: A](that: Seq[B]): View[A]
Computes the multiset intersection between this sequence and another sequence.
- that
the sequence of elements to intersect with.
- returns
a new sequence which contains all elements of this sequence which also appear in
that
. If an element valuex
appears n times inthat
, then the first n occurrences ofx
will be retained in the result, but any following occurrences will be omitted.
- Definition Classes
- SeqOps
def isDefinedAt(idx: Int): Boolean
Tests whether this sequence contains given index.
The implementations of methods apply
and isDefinedAt
turn a Seq[A]
into a PartialFunction[Int, A]
.
- idx
the index to test
- returns
true
if this sequence contains an element at positionidx
,false
otherwise.
- Definition Classes
- SeqOps
def isEmpty: Boolean
Tests whether the sequence is empty.
Note: Implementations in subclasses that are not repeatedly traversable must take care not to consume any elements when isEmpty
is called.
- returns
true
if the sequence contains no elements,false
otherwise.
- Definition Classes
- Id → SeqOps → IterableOnceOps
final def isInstanceOf[T0]: Boolean
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.
- returns
true
if the receiver object is an instance of erasure of typeT0
;false
otherwise.
- Definition Classes
- Any
def isTraversableAgain: Boolean
Tests whether this iterable collection can be repeatedly traversed. Always true for Iterables and false for Iterators unless overridden.
- returns
true
if it is repeatedly traversable,false
otherwise.
- Definition Classes
- IterableOps → IterableOnceOps
def iterableFactory: IterableFactory[View]
The companion object of this view, providing various factory methods.
- Definition Classes
- View → Iterable → IterableOps
- Note
When implementing a custom collection type and refining
CC
to the new type, this method needs to be overridden to return a factory for the new type (the compiler will issue an error otherwise).
def iterator: Iterator[A]
Iterator can be used only once
- Definition Classes
- Id → IterableOnce
def knownSize: Int
- returns
The number of elements in this sequence, if it can be cheaply computed, -1 otherwise. Cheaply usually means: Not requiring a collection traversal.
- Definition Classes
- Id → IterableOnce
def last: A
Selects the last element.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- returns
The last element of this iterable collection.
- Definition Classes
- IterableOps
- Exceptions thrown
NoSuchElementException
If the iterable collection is empty.
def lastIndexOf[B >: A](elem: B, end: Int = length - 1): Int
Finds index of last occurrence of some value in this sequence before or at a given end index.
Note: will not terminate for infinite-sized collections.
- B
the type of the element
elem
.- elem
the element value to search for.
- end
the end index.
- returns
the index
<= end
of the last element of this sequence that is equal (as determined by==
) toelem
, or-1
, if none exists.
- Definition Classes
- SeqOps
def lastIndexOfSlice[B >: A](that: Seq[B]): Int
Finds last index where this sequence contains a given sequence as a slice.
Note: will not terminate for infinite-sized collections.
- that
the sequence to test
- returns
the last index such that the elements of this sequence starting at this index match the elements of sequence
that
, or-1
of no such subsequence exists.
- Definition Classes
- SeqOps
- Annotations
- @deprecatedOverriding("Override lastIndexOfSlice(that, end) instead - lastIndexOfSlice(that) calls lastIndexOfSlice(that, Int.MaxValue)", "2.13.0")
def lastIndexOfSlice[B >: A](that: Seq[B], end: Int): Int
Finds last index before or at a given end index where this sequence contains a given sequence as a slice.
Note: will not terminate for infinite-sized collections.
- that
the sequence to test
- end
the end index
- returns
the last index
<= end
such that the elements of this sequence starting at this index match the elements of sequencethat
, or-1
of no such subsequence exists.
- Definition Classes
- SeqOps
def lastIndexWhere(p: (A) => Boolean): Int
Finds index of last element satisfying some predicate.
Note: will not terminate for infinite-sized collections.
- p
the predicate used to test elements.
- returns
the index of the last element of this sequence that satisfies the predicate
p
, or-1
, if none exists.
- Definition Classes
- SeqOps
- Annotations
- @deprecatedOverriding("Override lastIndexWhere(p, end) instead - lastIndexWhere(p) calls lastIndexWhere(p, Int.MaxValue)", "2.13.0")
def lastIndexWhere(p: (A) => Boolean, end: Int): Int
Finds index of last element satisfying some predicate before or at given end index.
Note: will not terminate for infinite-sized collections.
- p
the predicate used to test elements.
- returns
the index
<= end
of the last element of this sequence that satisfies the predicatep
, or-1
, if none exists.
- Definition Classes
- SeqOps
def lastOption: Option[A]
Optionally selects the last element.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- returns
the last element of this iterable collection$ if it is nonempty,
None
if it is empty.
- Definition Classes
- IterableOps
def lazyZip[B](that: Iterable[B]): LazyZip2[A, B, Id.this.type]
Analogous to zip
except that the elements in each collection are not consumed until a strict operation is invoked on the returned LazyZip2
decorator.
Calls to lazyZip
can be chained to support higher arities (up to 4) without incurring the expense of constructing and deconstructing intermediary tuples.
val xs = List(1, 2, 3) val res = (xs lazyZip xs lazyZip xs lazyZip xs).map((a, b, c, d) => a + b + c + d) // res == List(4, 8, 12)
- B
the type of the second element in each eventual pair
- that
the iterable providing the second element of each eventual pair
- returns
a decorator
LazyZip2
that allows strict operations to be performed on the lazily evaluated pairs or chained calls tolazyZip
. Implicit conversion toIterable[(A, B)]
is also supported.
- Definition Classes
- Iterable
def length: Int
The length (number of elements) of the sequence. size
is an alias for length
in Seq
collections.
def lengthCompare(that: Iterable[_]): Int
Compares the length of this sequence to the size of another Iterable
.
- that
the
Iterable
whose size is compared with this sequence's length.- returns
-
A value
x
wherex < 0 if this.length < that.size x == 0 if this.length == that.size x > 0 if this.length > that.size
The method as implemented here does not call
length
orsize
directly; its running time isO(this.length min that.size)
instead ofO(this.length + that.size)
. The method should be overridden if computingsize
is cheap andknownSize
returns-1
.
- Definition Classes
- SeqOps
def lengthCompare(len: Int): Int
Compares the length of this sequence to a test value.
- len
the test value that gets compared with the length.
- returns
-
A value
x
wherex < 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 isO(length min len)
instead ofO(length)
. The method should be overridden if computinglength
is cheap andknownSize
returns-1
.
final def lengthIs: SizeCompareOps
Returns a value class containing operations for comparing the length of this sequence to a test value.
These operations are implemented in terms of lengthCompare(Int)
, and allow the following more readable usages:
this.lengthIs < len // this.lengthCompare(len) < 0 this.lengthIs <= len // this.lengthCompare(len) <= 0 this.lengthIs == len // this.lengthCompare(len) == 0 this.lengthIs != len // this.lengthCompare(len) != 0 this.lengthIs >= len // this.lengthCompare(len) >= 0 this.lengthIs > len // this.lengthCompare(len) > 0
def map[B](f: (A) => B): SeqView[B]
Builds a new view by applying a function to all elements of this view.
- B
the element type of the returned view.
- f
the function to apply to each element.
- returns
a new view resulting from applying the given function
f
to each element of this view and collecting the results.
- Definition Classes
- SeqView → IterableOps → IterableOnceOps
- Note
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.
def max[B >: A](implicit ord: math.Ordering[B]): A
Finds the largest element.
- B
The type over which the ordering is defined.
- ord
An ordering to be used for comparing elements.
- returns
the largest element of this collection with respect to the ordering
ord
.
- Definition Classes
- IterableOnceOps
- Exceptions thrown
UnsupportedOperationException
if this collection is empty.
def maxBy[B](f: (A) => B)(implicit cmp: math.Ordering[B]): A
Finds the first element which yields the largest value measured by function f.
- B
The result type of the function f.
- f
The measuring function.
- cmp
An ordering to be used for comparing elements.
- returns
the first element of this collection with the largest value measured by function f with respect to the ordering
cmp
.
- Definition Classes
- IterableOnceOps
- Exceptions thrown
UnsupportedOperationException
if this collection is empty.
def maxByOption[B](f: (A) => B)(implicit cmp: math.Ordering[B]): Option[A]
Finds the first element which yields the largest value measured by function f.
- B
The result type of the function f.
- f
The measuring function.
- cmp
An ordering to be used for comparing elements.
- returns
an option value containing the first element of this collection with the largest value measured by function f with respect to the ordering
cmp
.
- Definition Classes
- IterableOnceOps
def maxOption[B >: A](implicit ord: math.Ordering[B]): Option[A]
Finds the largest element.
- B
The type over which the ordering is defined.
- ord
An ordering to be used for comparing elements.
- returns
an option value containing the largest element of this collection with respect to the ordering
ord
.
- Definition Classes
- IterableOnceOps
def min[B >: A](implicit ord: math.Ordering[B]): A
Finds the smallest element.
- B
The type over which the ordering is defined.
- ord
An ordering to be used for comparing elements.
- returns
the smallest element of this collection with respect to the ordering
ord
.
- Definition Classes
- IterableOnceOps
- Exceptions thrown
UnsupportedOperationException
if this collection is empty.
def minBy[B](f: (A) => B)(implicit cmp: math.Ordering[B]): A
Finds the first element which yields the smallest value measured by function f.
- B
The result type of the function f.
- f
The measuring function.
- cmp
An ordering to be used for comparing elements.
- returns
the first element of this collection with the smallest value measured by function f with respect to the ordering
cmp
.
- Definition Classes
- IterableOnceOps
- Exceptions thrown
UnsupportedOperationException
if this collection is empty.
def minByOption[B](f: (A) => B)(implicit cmp: math.Ordering[B]): Option[A]
Finds the first element which yields the smallest value measured by function f.
- B
The result type of the function f.
- f
The measuring function.
- cmp
An ordering to be used for comparing elements.
- returns
an option value containing the first element of this collection with the smallest value measured by function f with respect to the ordering
cmp
.
- Definition Classes
- IterableOnceOps
def minOption[B >: A](implicit ord: math.Ordering[B]): Option[A]
Finds the smallest element.
- B
The type over which the ordering is defined.
- ord
An ordering to be used for comparing elements.
- returns
an option value containing the smallest element of this collection with respect to the ordering
ord
.
- Definition Classes
- IterableOnceOps
final def mkString: String
Displays all elements of this collection in a string.
Delegates to addString, which can be overridden.
- returns
a string representation of this collection. In the resulting string the string representations (w.r.t. the method
toString
) of all elements of this collection follow each other without any separator string.
- Definition Classes
- IterableOnceOps
- Annotations
- @inline()
final def mkString(sep: String): String
Displays all elements of this collection in a string using a separator string.
Delegates to addString, which can be overridden.
- sep
the separator string.
- returns
a string representation of this collection. In the resulting string the string representations (w.r.t. the method
toString
) of all elements of this collection are separated by the stringsep
.
- Definition Classes
- IterableOnceOps
- Annotations
- @inline()
List(1, 2, 3).mkString("|") = "1|2|3"
final def mkString(start: String, sep: String, end: String): String
Displays all elements of this collection in a string using start, end, and separator strings.
Delegates to addString, which can be overridden.
- start
the starting string.
- sep
the separator string.
- end
the ending string.
- returns
a string representation of this collection. The resulting string begins with the string
start
and ends with the stringend
. Inside, the string representations (w.r.t. the methodtoString
) of all elements of this collection are separated by the stringsep
.
- Definition Classes
- IterableOnceOps
List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"
final def ne(arg0: AnyRef): Boolean
Equivalent to !(this eq that)
.
- returns
true
if the argument is not a reference to the receiver object;false
otherwise.
- Definition Classes
- AnyRef
def newSpecificBuilder: Builder[A, View[A]]
- returns
a strict builder for the same collection type. Note that in the case of lazy collections (e.g. View or immutable.LazyList), it is possible to implement this method but the resulting
Builder
will break laziness. As a consequence, operations should preferably be implemented withfromSpecific
instead of this method.
- Attributes
- protected
- Definition Classes
- IterableFactoryDefaults → IterableOps
- Note
-
When implementing a custom collection type and refining
,C
to the new type, this method needs to be overridden (the compiler will issue an error otherwise). In the common case whereC =:= CC[A]
, this can be done by mixing in the IterableFactoryDefaults trait, which implements the method using iterableFactory.As witnessed by the
@uncheckedVariance
annotation, using this method might be unsound. However, as long as the returned builder is only fed withA
values taken fromthis
instance, it is safe.
def nonEmpty: Boolean
Tests whether the collection is not empty.
- returns
true
if the collection contains at least one element,false
otherwise.
- Definition Classes
- IterableOnceOps
- Annotations
- @deprecatedOverriding("nonEmpty is defined as !isEmpty; override isEmpty instead", "2.13.0")
final def notify(): Unit
Wakes up a single thread that is waiting on the receiver object's monitor.
- Definition Classes
- AnyRef
- Annotations
- @native()
- Note
not specified by SLS as a member of AnyRef
final def notifyAll(): Unit
Wakes up all threads that are waiting on the receiver object's monitor.
- Definition Classes
- AnyRef
- Annotations
- @native()
- Note
not specified by SLS as a member of AnyRef
def occCounts[B](sq: Seq[B]): mutable.Map[B, Int]
- Attributes
- protected[scala.collection]
- Definition Classes
- SeqOps
def padTo[B >: A](len: Int, elem: B): View[B]
A copy of this sequence with an element value appended until a given target length is reached.
- B
the element type of the returned sequence.
- len
the target length
- elem
the padding value
- returns
a new sequence consisting of all elements of this sequence followed by the minimal number of occurrences of
elem
so that the resulting collection has a length of at leastlen
.
- Definition Classes
- SeqOps
def partition(p: (A) => Boolean): (View[A], View[A])
A pair of, first, all elements that satisfy predicate p
and, second, all elements that do not. Interesting because it splits a collection in two.
The default implementation provided here needs to traverse the collection twice. Strict collections have an overridden version of partition
in StrictOptimizedIterableOps
, which requires only a single traversal.
- Definition Classes
- IterableOps
def partitionMap[A1, A2](f: (A) => Either[A1, A2]): (View[A1], View[A2])
Applies a function f
to each element of the iterable collection and returns a pair of iterable collections: the first one made of those values returned by f
that were wrapped in scala.util.Left, and the second one made of those wrapped in scala.util.Right.
Example:
val xs = Iterable(1, "one", 2, "two", 3, "three") partitionMap { case i: Int => Left(i) case s: String => Right(s) } // xs == (Iterable(1, 2, 3), // Iterable(one, two, three))
- A1
the element type of the first resulting collection
- A2
the element type of the second resulting collection
- f
the 'split function' mapping the elements of this iterable collection to an scala.util.Either
- returns
a pair of iterable collections: the first one made of those values returned by
f
that were wrapped in scala.util.Left, and the second one made of those wrapped in scala.util.Right.
- Definition Classes
- IterableOps
def patch[B >: A](from: Int, other: IterableOnce[B], replaced: Int): View[B]
Produces a new sequence where a slice of elements in this sequence is replaced by another sequence.
Patching at negative indices is the same as patching starting at 0. Patching at indices at or larger than the length of the original sequence appends the patch to the end. If more values are replaced than actually exist, the excess is ignored.
- B
the element type of the returned sequence.
- from
the index of the first replaced element
- other
the replacement sequence
- replaced
the number of elements to drop in the original sequence
- returns
a new sequence consisting of all elements of this sequence except that
replaced
elements starting fromfrom
are replaced by all the elements ofother
.
- Definition Classes
- SeqOps
def permutations: Iterator[View[A]]
Iterates over distinct permutations.
Note: Even when applied to a view or a lazy collection it will always force the elements.
- returns
An Iterator which traverses the distinct permutations of this sequence.
- Definition Classes
- SeqOps
"abb".permutations = Iterator(abb, bab, bba)
def prepended[B >: A](elem: B): SeqView[B]
A copy of the view with an element prepended.
Also, the original view is not modified, so you will want to capture the result.
Example:
scala> val x = List(1) x: List[Int] = List(1) scala> val y = 2 +: x y: List[Int] = List(2, 1) scala> println(x) List(1)
- B
the element type of the returned view.
- elem
the prepended element
- returns
a new view consisting of
value
followed by all elements of this view.
def prependedAll[B >: A](prefix: SomeSeqOps[B]): SeqView[B]
- Definition Classes
- SeqView
def prependedAll[B >: A](prefix: IterableOnce[B]): View[B]
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.
- B
the element type of the returned collection.
- prefix
the iterable to prepend.
- returns
a new sequence which contains all elements of
prefix
followed by all the elements of this sequence.
- Definition Classes
- SeqOps
def product[B >: A](implicit num: math.Numeric[B]): B
Multiplies up the elements of this collection.
- B
the result type of the
*
operator.- num
an implicit parameter defining a set of numeric operations which includes the
*
operator to be used in forming the product.- returns
the product of all elements of this collection with respect to the
*
operator innum
.
- Definition Classes
- IterableOnceOps
def reduce[B >: A](op: (B, B) => B): B
Reduces the elements of this collection using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
- B
A type parameter for the binary operator, a supertype of
A
.- op
A binary operator that must be associative.
- returns
The result of applying reduce operator
op
between all the elements if the collection is nonempty.
- Definition Classes
- IterableOnceOps
- Exceptions thrown
UnsupportedOperationException
if this collection is empty.
def reduceLeft[B >: A](op: (B, A) => B): B
Applies a binary operator to all elements of this 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.
- B
the result type of the binary operator.
- op
the binary operator.
- returns
-
the result of inserting
op
between consecutive elements of this 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 collection.
- Definition Classes
- IterableOnceOps
- Exceptions thrown
UnsupportedOperationException
if this collection is empty.
def reduceLeftOption[B >: A](op: (B, A) => B): Option[B]
Optionally applies a binary operator to all elements of this 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.
- B
the result type of the binary operator.
- op
the binary operator.
- returns
an option value containing the result of
reduceLeft(op)
if this collection is nonempty,None
otherwise.
- Definition Classes
- IterableOnceOps
def reduceOption[B >: A](op: (B, B) => B): Option[B]
Reduces the elements of this collection, if any, using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
- B
A type parameter for the binary operator, a supertype of
A
.- op
A binary operator that must be associative.
- returns
An option value containing result of applying reduce operator
op
between all the elements if the collection is nonempty, andNone
otherwise.
- Definition Classes
- IterableOnceOps
def reduceRight[B >: A](op: (A, B) => B): B
Applies a binary operator to all elements of this 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.
- B
the result type of the binary operator.
- op
the binary operator.
- returns
-
the result of inserting
op
between consecutive elements of this 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 collection.
- Definition Classes
- IterableOnceOps
- Exceptions thrown
UnsupportedOperationException
if this collection is empty.
def reduceRightOption[B >: A](op: (A, B) => B): Option[B]
Optionally applies a binary operator to all elements of this 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.
- B
the result type of the binary operator.
- op
the binary operator.
- returns
an option value containing the result of
reduceRight(op)
if this collection is nonempty,None
otherwise.
- Definition Classes
- IterableOnceOps
def reverse: SeqView[A]
Returns new view with elements in reversed order.
Note: will not terminate for infinite-sized collections.
Note: Even when applied to a view or a lazy collection it will always force the elements.
- returns
A new view with all elements of this view in reversed order.
def reverseIterator: Iterator[A]
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.
- returns
an iterator yielding the elements of this sequence in reversed order
- Definition Classes
- SeqOps
def reversed: Iterable[A]
- Attributes
- protected
- Definition Classes
- IterableOnceOps
def sameElements[B >: A](that: IterableOnce[B]): Boolean
Are the elements of this collection the same (and in the same order) as those of that
?
- Definition Classes
- SeqOps
def scan[B >: A](z: B)(op: (B, B) => B): View[B]
Computes a prefix scan of the elements of the collection.
Note: The neutral element z
may be applied more than once.
- B
element type of the resulting collection
- z
neutral element for the operator
op
- op
the associative operator for the scan
- returns
a new iterable collection containing the prefix scan of the elements in this iterable collection
- Definition Classes
- IterableOps
def scanLeft[B](z: B)(op: (B, A) => B): View[B]
Produces a iterable collection containing cumulative results of applying the operator going left to right, including the initial value.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- B
the type of the elements in the resulting collection
- z
the initial value
- op
the binary operator applied to the intermediate result and the element
- returns
collection with intermediate results
- Definition Classes
- IterableOps → IterableOnceOps
- Note
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.
def scanRight[B](z: B)(op: (A, B) => B): View[B]
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.
Note: Even when applied to a view or a lazy collection it will always force the elements.
Example:
List(1, 2, 3, 4).scanRight(0)(_ + _) == List(10, 9, 7, 4, 0)
- B
the type of the elements in the resulting collection
- z
the initial value
- op
the binary operator applied to the intermediate result and the element
- returns
collection with intermediate results
- Definition Classes
- IterableOps
def search[B >: A](elem: B, from: Int, to: Int)(implicit ord: Ordering[B]): SearchResult
Search within an interval in this sorted sequence for a specific element. If this sequence is an IndexedSeq
, a binary search is used. Otherwise, a linear search is used.
The sequence should be sorted with the same Ordering
before calling; otherwise, the results are undefined.
- elem
the element to find.
- from
the index where the search starts.
- to
the index following where the search ends.
- ord
the ordering to be used to compare elements.
- returns
a
Found
value containing the index corresponding to the element in the sequence, or theInsertionPoint
where the element would be inserted if the element is not in the sequence.
- Definition Classes
- SeqOps
- Note
if
to <= from
, the search space is empty, and anInsertionPoint
atfrom
is returned- See also
-
scala.collection.SeqOps, method
sorted
def search[B >: A](elem: B)(implicit ord: Ordering[B]): SearchResult
Search this sorted sequence for a specific element. If the sequence is an IndexedSeq
, a binary search is used. Otherwise, a linear search is used.
The sequence should be sorted with the same Ordering
before calling; otherwise, the results are undefined.
- elem
the element to find.
- ord
the ordering to be used to compare elements.
- returns
a
Found
value containing the index corresponding to the element in the sequence, or theInsertionPoint
where the element would be inserted if the element is not in the sequence.
- Definition Classes
- SeqOps
- See also
-
scala.collection.SeqOps, method
sorted
def segmentLength(p: (A) => Boolean, from: Int): Int
Computes length of longest segment whose elements all satisfy some predicate.
Note: may not terminate for infinite-sized collections.
- p
the predicate used to test elements.
- from
the index where the search starts.
- returns
the length of the longest segment of this sequence starting from index
from
such that every element of the segment satisfies the predicatep
.
- Definition Classes
- SeqOps
final def segmentLength(p: (A) => Boolean): Int
Computes length of longest segment whose elements all satisfy some predicate.
Note: may not terminate for infinite-sized collections.
- p
the predicate used to test elements.
- returns
the length of the longest segment of this sequence such that every element of the segment satisfies the predicate
p
.
- Definition Classes
- SeqOps
final def size: Int
The size of this sequence.
Note: will not terminate for infinite-sized collections.
- returns
the number of elements in this sequence.
- Definition Classes
- SeqOps → IterableOnceOps
final def sizeCompare(that: Iterable[_]): Int
Compares the size of this sequence to the size of another Iterable
.
- that
the
Iterable
whose size is compared with this sequence's size.- returns
-
A value
x
wherex < 0 if this.size < that.size x == 0 if this.size == that.size x > 0 if this.size > that.size
The method as implemented here does not call
size
directly; its running time isO(this.size min that.size)
instead ofO(this.size + that.size)
. The method should be overridden if computingsize
is cheap andknownSize
returns-1
.
- Definition Classes
- SeqOps → IterableOps
final def sizeCompare(otherSize: Int): Int
Compares the size of this sequence to a test value.
- otherSize
the test value that gets compared with the size.
- returns
-
A value
x
wherex < 0 if this.size < otherSize x == 0 if this.size == otherSize x > 0 if this.size > otherSize
The method as implemented here does not call
size
directly; its running time isO(size min otherSize)
instead ofO(size)
. The method should be overridden if computingsize
is cheap andknownSize
returns-1
.
- Definition Classes
- SeqOps → IterableOps
- See also
final def sizeIs: SizeCompareOps
Returns a value class containing operations for comparing the size of this iterable collection to a test value.
These operations are implemented in terms of sizeCompare(Int)
, and allow the following more readable usages:
this.sizeIs < size // this.sizeCompare(size) < 0 this.sizeIs <= size // this.sizeCompare(size) <= 0 this.sizeIs == size // this.sizeCompare(size) == 0 this.sizeIs != size // this.sizeCompare(size) != 0 this.sizeIs >= size // this.sizeCompare(size) >= 0 this.sizeIs > size // this.sizeCompare(size) > 0
- Definition Classes
- IterableOps
- Annotations
- @inline()
def slice(from: Int, until: Int): View[A]
Selects an interval of elements. The returned iterable 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.
- from
the lowest index to include from this iterable collection.
- until
the lowest index to EXCLUDE from this iterable collection.
- returns
a iterable collection containing the elements greater than or equal to index
from
extending up to (but not including) indexuntil
of this iterable collection.
- Definition Classes
- IterableOps → IterableOnceOps
- Note
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.
def sliding(size: Int, step: Int): Iterator[View[A]]
Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.)
- size
the number of elements per group
- step
the distance between the first elements of successive groups
- returns
An iterator producing iterable collections of size
size
, except the last element (which may be the only element) will be truncated if there are fewer thansize
elements remaining to be grouped.
- Definition Classes
- IterableOps
- See also
scala.collection.Iterator, method
sliding
def sliding(size: Int): Iterator[View[A]]
Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped
.) The "sliding window" step is set to one.
- size
the number of elements per group
- returns
An iterator producing iterable collections of size
size
, except the last element (which may be the only element) will be truncated if there are fewer thansize
elements remaining to be grouped.
- Definition Classes
- IterableOps
- See also
scala.collection.Iterator, method
sliding
def sortBy[B](f: (A) => B)(implicit ord: Ordering[B]): View[A]
Sorts this sequence according to the Ordering which results from transforming an implicitly given Ordering with a transformation function.
Note: will not terminate for infinite-sized collections.
Note: Even when applied to a view or a lazy collection it will always force the elements.
The sort is stable. That is, elements that are equal (as determined by ord.compare
) appear in the same order in the sorted sequence as in the original.
- B
the target type of the transformation
f
, and the type where the orderingord
is defined.- f
the transformation function mapping elements to some other domain
B
.- ord
the ordering assumed on domain
B
.- returns
a sequence consisting of the elements of this sequence sorted according to the ordering where
x < y
iford.lt(f(x), f(y))
.
- Definition Classes
- SeqOps
- See also
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)
def sortWith(lt: (A, A) => Boolean): View[A]
Sorts this sequence according to a comparison function.
Note: will not terminate for infinite-sized collections.
Note: Even when applied to a view or a lazy collection it will always force the elements.
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.
- lt
the comparison function which tests whether its first argument precedes its second argument in the desired ordering.
- returns
a sequence consisting of the elements of this sequence sorted according to the comparison function
lt
.
- Definition Classes
- SeqOps
List("Steve", "Tom", "John", "Bob").sortWith(_.compareTo(_) < 0) = List("Bob", "John", "Steve", "Tom")
def sorted[B >: A](implicit ord: Ordering[B]): SeqView[A]
Sorts this view according to an Ordering.
The sort is stable. That is, elements that are equal (as determined by ord.compare
) appear in the same order in the sorted sequence as in the original.
- ord
the ordering to be used to compare elements.
- returns
a view consisting of the elements of this view sorted according to the ordering
ord
.
- Definition Classes
- SeqView → SeqOps
- See also
scala.math.Ordering Note: Even when applied to a view or a lazy collection it will always force the elements.
def span(p: (A) => Boolean): (View[A], View[A])
Splits this 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.
- p
the test predicate
- returns
a pair consisting of the longest prefix of this iterable collection whose elements all satisfy
p
, and the rest of this iterable collection.
- Definition Classes
- IterableOps → IterableOnceOps
- Note
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterators that were returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterators as well.
def splitAt(n: Int): (View[A], View[A])
Splits this iterable collection into a prefix/suffix pair 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.
- n
the position at which to split.
- returns
a pair of iterable collections consisting of the first
n
elements of this iterable collection, and the other elements.
- Definition Classes
- IterableOps → IterableOnceOps
- Note
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterators that were returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterators as well.
def startsWith[B >: A](that: IterableOnce[B], offset: Int = 0): Boolean
Tests whether this 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.
- that
the sequence to test
- offset
the index where the sequence is searched.
- returns
true
if the sequencethat
is contained in this sequence at indexoffset
, otherwisefalse
.
- Definition Classes
- SeqOps
def stepper[S <: Stepper[_]](implicit shape: StepperShape[A, S]): S
Returns a Stepper for the elements of this collection.
The Stepper enables creating a Java stream to operate on the collection, see scala.jdk.StreamConverters. For collections holding primitive values, the Stepper can be used as an iterator which doesn't box the elements.
The implicit StepperShape parameter defines the resulting Stepper type according to the element type of this collection.
-
For collections of
Int
, Short
, Byte
or Char
, an IntStepper is returnedFor collections of Double
or Float
, a DoubleStepper is returnedFor collections of Long
a LongStepper is returnedFor any other element type, an AnyStepper is returnedNote that this method is overridden in subclasses and the return type is refined to S with EfficientSplit
, for example IndexedSeqOps.stepper. For Steppers marked with scala.collection.Stepper.EfficientSplit, the converters in scala.jdk.StreamConverters allow creating parallel streams, whereas bare Steppers can be converted only to sequential streams.
- Definition Classes
- IterableOnce
def stringPrefix: String
- Attributes
- protected[this]
- Definition Classes
- SeqView → View → Iterable
- Annotations
- @deprecatedOverriding("Compatibility override", "2.13.0")
def sum[B >: A](implicit num: math.Numeric[B]): B
Sums up the elements of this collection.
- B
the result type of the
+
operator.- num
an implicit parameter defining a set of numeric operations which includes the
+
operator to be used in forming the sum.- returns
the sum of all elements of this collection with respect to the
+
operator innum
.
- Definition Classes
- IterableOnceOps
final def synchronized[T0](arg0: => T0): T0
- Definition Classes
- AnyRef
def tail: View[A]
The rest of the collection without its first element.
- Definition Classes
- IterableOps
def tails: Iterator[View[A]]
Iterates over the tails of this iterable collection. The first value will be this iterable collection and the final one will be an empty iterable collection, with the intervening values the results of successive applications of tail
.
- returns
an iterator over all the tails of this iterable collection
- Definition Classes
- IterableOps
List(1,2,3).tails = Iterator(List(1,2,3), List(2,3), List(3), Nil)
def take(n: Int): SeqView[A]
Selects the first n elements.
- n
the number of elements to take from this view.
- returns
a view consisting only of the first
n
elements of this view, or else the whole view, if it has less thann
elements. Ifn
is negative, returns an empty view.
- Definition Classes
- SeqView → IterableOps → IterableOnceOps
- Note
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.
def takeRight(n: Int): SeqView[A]
Selects the last n elements.
- n
the number of elements to take from this view.
- returns
a view consisting only of the last
n
elements of this view, or else the whole view, if it has less thann
elements. Ifn
is negative, returns an empty view.
- Definition Classes
- SeqView → IterableOps
def takeWhile(p: (A) => Boolean): View[A]
Takes longest prefix of elements that satisfy a predicate.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- p
The predicate used to test elements.
- returns
the longest prefix of this iterable collection whose elements all satisfy the predicate
p
.
- Definition Classes
- IterableOps → IterableOnceOps
def tapEach[U](f: (A) => U): SeqView[A]
Applies a side-effecting function to each element in this collection. Strict collections will apply f
to their elements immediately, while lazy collections like Views and LazyLists will only apply f
on each element if and when that element is evaluated, and each time that element is evaluated.
- U
the return type of f
- f
a function to apply to each element in this view
- returns
The same logical collection as this
- Definition Classes
- SeqView → IterableOps → IterableOnceOps
def to[C1](factory: Factory[A, C1]): C1
Given a collection factory factory
, convert this collection to the appropriate representation for the current element type A
. Example uses:
xs.to(List) xs.to(ArrayBuffer) xs.to(BitSet) // for xs: Iterable[Int]
- Definition Classes
- IterableOnceOps
def toArray[B >: A](implicit arg0: ClassTag[B]): Array[B]
Convert collection to array.
- Definition Classes
- IterableOnceOps
final def toBuffer[B >: A]: Buffer[B]
- Definition Classes
- IterableOnceOps
- Annotations
- @inline()
def toIndexedSeq: immutable.IndexedSeq[A]
- Definition Classes
- IterableOnceOps
final def toIterable: Id.this.type
- returns
This collection as an
Iterable[A]
. No new collection will be built ifthis
is already anIterable[A]
.
- Definition Classes
- Iterable → IterableOps
def toList: immutable.List[A]
- Definition Classes
- IterableOnceOps
def toMap[K, V](implicit ev: <:<[A, (K, V)]): immutable.Map[K, V]
- Definition Classes
- IterableOnceOps
def toSeq: immutable.Seq[A]
- returns
This collection as a
Seq[A]
. This is equivalent toto(Seq)
but might be faster.
- Definition Classes
- IterableOnceOps
def toSet[B >: A]: immutable.Set[B]
- Definition Classes
- IterableOnceOps
def toString(): String
Converts this view to a string.
- returns
a string representation of this collection. By default this string consists of the
className
of this view, followed by all elements separated by commas and enclosed in parentheses.
def toVector: immutable.Vector[A]
- Definition Classes
- IterableOnceOps
def transpose[B](implicit asIterable: (A) => Iterable[B]): View[View[B]]
Transposes this iterable collection of iterable collections into a iterable collection of iterable collections.
The resulting collection's type will be guided by the static type of iterable collection. For example:
val xs = List( Set(1, 2, 3), Set(4, 5, 6)).transpose // xs == List( // List(1, 4), // List(2, 5), // List(3, 6)) val ys = Vector( List(1, 2, 3), List(4, 5, 6)).transpose // ys == Vector( // Vector(1, 4), // Vector(2, 5), // Vector(3, 6))
Note: Even when applied to a view or a lazy collection it will always force the elements.
- B
the type of the elements of each iterable collection.
- asIterable
an implicit conversion which asserts that the element type of this iterable collection is an
Iterable
.- returns
a two-dimensional iterable collection of iterable collections which has as nth row the nth column of this iterable collection.
- Definition Classes
- IterableOps
- Exceptions thrown
IllegalArgumentException
if all collections in this iterable collection are not of the same size.
def unzip[A1, A2](implicit asPair: (A) => (A1, A2)): (View[A1], View[A2])
Converts this iterable collection of pairs into two collections of the first and second half of each pair.
val xs = Iterable( (1, "one"), (2, "two"), (3, "three")).unzip // xs == (Iterable(1, 2, 3), // Iterable(one, two, three))
- A1
the type of the first half of the element pairs
- A2
the type of the second half of the element pairs
- asPair
an implicit conversion which asserts that the element type of this iterable collection is a pair.
- returns
a pair of iterable collections, containing the first, respectively second half of each element pair of this iterable collection.
- Definition Classes
- IterableOps
def unzip3[A1, A2, A3](implicit asTriple: (A) => (A1, A2, A3)): (View[A1], View[A2], View[A3])
Converts this iterable collection of triples into three collections of the first, second, and third element of each triple.
val xs = Iterable( (1, "one", '1'), (2, "two", '2'), (3, "three", '3')).unzip3 // xs == (Iterable(1, 2, 3), // Iterable(one, two, three), // Iterable(1, 2, 3))
- A1
the type of the first member of the element triples
- A2
the type of the second member of the element triples
- A3
the type of the third member of the element triples
- asTriple
an implicit conversion which asserts that the element type of this iterable collection is a triple.
- returns
a triple of iterable collections, containing the first, second, respectively third member of each element triple of this iterable collection.
- Definition Classes
- IterableOps
def updated[B >: A](index: Int, elem: B): View[B]
A copy of this sequence with one single replaced element.
- B
the element type of the returned sequence.
- index
the position of the replacement
- elem
the replacing element
- returns
a new sequence which is a copy of this sequence with the element at position
index
replaced byelem
.
- Definition Classes
- SeqOps
- Exceptions thrown
IndexOutOfBoundsException
ifindex
does not satisfy0 <= index < length
. In case of a lazy collection this exception may be thrown at a later time or not at all (if the end of the collection is never evaluated).
def view: SeqView[A]
A view over the elements of this collection.
- Definition Classes
- SeqView → View → SeqOps → IterableOps
final def wait(): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
final def wait(arg0: Long, arg1: Int): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
final def wait(arg0: Long): Unit
def withFilter(p: (A) => Boolean): WithFilter[A, [_]View[_]]
Creates a non-strict filter of this 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.
- p
the predicate used to test elements.
- returns
an object of class
WithFilter
, which supportsmap
,flatMap
,foreach
, andwithFilter
operations. All these operations apply to those elements of this iterable collection which satisfy the predicatep
.
- Definition Classes
- IterableOps
def zip[B](that: IterableOnce[B]): View[(A, B)]
Returns a iterable collection formed from this 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.
- B
the type of the second half of the returned pairs
- that
The iterable providing the second half of each result pair
- returns
a new iterable collection containing pairs consisting of corresponding elements of this iterable collection and
that
. The length of the returned collection is the minimum of the lengths of this iterable collection andthat
.
- Definition Classes
- IterableOps
def zipAll[A1 >: A, B](that: Iterable[B], thisElem: A1, thatElem: B): View[(A1, B)]
Returns a iterable collection formed from this 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.
- that
the iterable providing the second half of each result pair
- thisElem
the element to be used to fill up the result if this iterable collection is shorter than
that
.- thatElem
the element to be used to fill up the result if
that
is shorter than this iterable collection.- returns
a new collection of type
That
containing pairs consisting of corresponding elements of this iterable collection andthat
. The length of the returned collection is the maximum of the lengths of this iterable collection andthat
. If this iterable collection is shorter thanthat
,thisElem
values are used to pad the result. Ifthat
is shorter than this iterable collection,thatElem
values are used to pad the result.
- Definition Classes
- IterableOps
def zipWithIndex: View[(A, Int)]
Zips this iterable collection with its indices.
- returns
A new iterable collection containing pairs consisting of all elements of this iterable collection paired with their index. Indices start at
0
.
- Definition Classes
- IterableOps → IterableOnceOps
- Note
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.
List("a", "b", "c").zipWithIndex == List(("a", 0), ("b", 1), ("c", 2))
© 2002-2019 EPFL, with contributions from Lightbend.
Licensed under the Apache License, Version 2.0.
https://www.scala-lang.org/api/2.13.0/scala/collection/SeqView$$Id.html
A view that doesn’t apply any transformation to an underlying sequence