class Unfold[A, S] extends AbstractView[A]
A view that uses a function f to produce elements of type A and update
an internal state S.
- Annotations
- @SerialVersionUID()
- Source
- View.scala
- Alphabetic
- By Inheritance
- Unfold
- AbstractView
- View
- Serializable
- AbstractIterable
- Iterable
- IterableFactoryDefaults
- IterableOps
- IterableOnceOps
- IterableOnce
- AnyRef
- Any
- by iterableOnceExtensionMethods
- by any2stringadd
- by StringFormat
- by Ensuring
- by ArrowAssoc
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- Public
- Protected
Value Members
- final def !=(arg0: Any): Boolean
Test two objects for inequality.
Test two objects for inequality.
- returns
trueif !(this == that), false otherwise.
- Definition Classes
- AnyRef → Any
- final def ##: Int
Equivalent to
x.hashCodeexcept for boxed numeric types andnull.Equivalent to
x.hashCodeexcept for boxed numeric types andnull. 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. Fornullreturns a hashcode wherenull.hashCodethrows aNullPointerException.- returns
a hash value consistent with ==
- Definition Classes
- AnyRef → Any
- def +(other: String): String
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toany2stringadd[Unfold[A, S]] performed by method any2stringadd in scala.Predef.
- Definition Classes
- any2stringadd
- final def ++[B >: A](suffix: IterableOnce[B]): View[B]
Alias for
concatAlias for
concat- Definition Classes
- IterableOps
- Annotations
- @inline()
- def ->[B](y: B): (Unfold[A, S], B)
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toArrowAssoc[Unfold[A, S]] performed by method ArrowAssoc in scala.Predef.
- Definition Classes
- ArrowAssoc
- Annotations
- @inline()
- final def ==(arg0: Any): Boolean
The expression
x == thatis equivalent toif (x eq null) that eq null else x.equals(that).The expression
x == thatis equivalent toif (x eq null) that eq null else x.equals(that).- returns
trueif the receiver object is equivalent to the argument;falseotherwise.
- Definition Classes
- AnyRef → Any
- final def addString(b: mutable.StringBuilder): mutable.StringBuilder
Appends all elements of this view to a string builder.
Appends all elements of this view to a string builder. The written text consists of the string representations (w.r.t. the method
toString) of all elements of this view 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
bto which elements were appended.
- Definition Classes
- IterableOnceOps
- Annotations
- @inline()
- final def addString(b: mutable.StringBuilder, sep: String): mutable.StringBuilder
Appends all elements of this view to a string builder using a separator string.
Appends all elements of this view 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 view, separated by the stringsep.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
bto 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 view to a string builder using start, end, and separator strings.
Appends all elements of this view to a string builder using start, end, and separator strings. The written text begins with the string
startand ends with the stringend. Inside, the string representations (w.r.t. the methodtoString) of all elements of this view are separated by the stringsep.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
bto which elements were appended.
- Definition Classes
- IterableOnceOps
- final def asInstanceOf[T0]: T0
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 aClassCastExceptionat runtime, while the expressionList(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
ClassCastExceptionif the receiver object is not an instance of the erasure of typeT0.
- def className: String
Defines the prefix of this object's
toStringrepresentation.Defines the prefix of this object's
toStringrepresentation.It is recommended to return the name of the concrete collection type, but not implementation subclasses. For example, for
ListMapthis 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
toStringapplied to this view. By default the string prefix is the simple name of the collection class view.
- Attributes
- protected[this]
- Definition Classes
- Iterable
- def clone(): AnyRef
Create a copy of the receiver object.
Create a copy of the receiver object.
The default implementation of the
clonemethod is platform dependent.- returns
a copy of the receiver object.
- final def coll: Unfold.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 view by applying a partial function to all elements of this view on which the function is defined.
Builds a new view by applying a partial function to all elements of this view on which the function is defined.
- B
the element type of the returned view.
- pf
the partial function which filters and maps the view.
- returns
a new view resulting from applying the given partial function
pfto each element on which it is defined and collecting the results. The order of the elements is preserved.
- Definition Classes
- IterableOps → IterableOnceOps
- def collectFirst[B](pf: PartialFunction[A, B]): Option[B]
Finds the first element of the view for which the given partial function is defined, and applies the partial function to it.
Finds the first element of the view 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
Noneif none exists.
- Definition Classes
- IterableOnceOps
Seq("a", 1, 5L).collectFirst({ case x: Int => x*10 }) = Some(10)
Example: - def concat[B >: A](suffix: IterableOnce[B]): View[B]
Returns a new view containing the elements from the left hand operand followed by the elements from the right hand operand.
Returns a new view containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the view 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 view which contains all elements of this view followed by all elements of
suffix.
- Definition Classes
- IterableOps
- def copyToArray[B >: A](xs: Array[B], start: Int, len: Int): Int
Copy elements to an array, returning the number of elements written.
Copy elements to an array, returning the number of elements written.
Fills the given array
xsstarting at indexstartwith at mostlenelements of this view.Copying will stop once either all the elements of this view have been copied, or the end of the array is reached, or
lenelements 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.
- def copyToArray[B >: A](xs: Array[B], start: Int): Int
Copy elements to an array, returning the number of elements written.
Copy elements to an array, returning the number of elements written.
Fills the given array
xsstarting at indexstartwith values of this view.Copying will stop once either all the elements of this view 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
- Definition Classes
- IterableOnceOps
- Annotations
- @deprecatedOverriding()
- Note
Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change.
- def copyToArray[B >: A](xs: Array[B]): Int
Copy elements to an array, returning the number of elements written.
Copy elements to an array, returning the number of elements written.
Fills the given array
xsstarting at indexstartwith values of this view.Copying will stop once either all the elements of this view 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
- Definition Classes
- IterableOnceOps
- Annotations
- @deprecatedOverriding()
- Note
Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change.
- 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.
Tests whether every element of this collection's iterator relates to the corresponding element of another collection by satisfying a test predicate.
Note: will not terminate for infinite-sized collections.
- B
the type of the elements of
that- that
the other collection
- p
the test predicate, which relates elements from both collections
- returns
trueif both collections have the same length andp(x, y)istruefor all corresponding elementsxof this iterator andyofthat, otherwisefalse
- Definition Classes
- IterableOnceOps
- def count(p: (A) => Boolean): Int
Counts the number of elements in the view which satisfy a predicate.
Counts the number of elements in the view which satisfy a predicate.
Note: will not terminate for infinite-sized collections.
- p
the predicate used to test elements.
- returns
the number of elements satisfying the predicate
p.
- Definition Classes
- IterableOnceOps
- def drop(n: Int): View[A]
Selects all elements except first n ones.
Selects all elements except first n ones.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- n
the number of elements to drop from this view.
- returns
a view consisting of all elements of this view except the first
nones, or else the empty view, if this view has less thannelements. Ifnis negative, don't drop any elements.
- Definition Classes
- IterableOps → IterableOnceOps
- def dropRight(n: Int): View[A]
Selects all elements except last n ones.
Selects all elements except last n ones.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- n
the number of elements to drop from this view.
- returns
a view consisting of all elements of this view except the last
nones, or else the empty view, if this view has less thannelements. Ifnis negative, don't drop any elements.
- Definition Classes
- IterableOps
- def dropWhile(p: (A) => Boolean): View[A]
Drops longest prefix of elements that satisfy a predicate.
Drops longest prefix of elements that satisfy a predicate.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- p
The predicate used to test elements.
- returns
the longest suffix of this view whose first element does not satisfy the predicate
p.
- Definition Classes
- IterableOps → IterableOnceOps
- def empty: View[A]
The empty iterable of the same type as this iterable
The empty iterable of the same type as this iterable
- returns
an empty iterable of type
C.
- Definition Classes
- View → IterableFactoryDefaults → IterableOps
- def ensuring(cond: (Unfold[A, S]) => Boolean, msg: => Any): Unfold[A, S]
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toEnsuring[Unfold[A, S]] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
- def ensuring(cond: (Unfold[A, S]) => Boolean): Unfold[A, S]
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toEnsuring[Unfold[A, S]] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
- def ensuring(cond: Boolean, msg: => Any): Unfold[A, S]
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toEnsuring[Unfold[A, S]] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
- def ensuring(cond: Boolean): Unfold[A, S]
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toEnsuring[Unfold[A, S]] 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).Tests whether the argument (
that) is a reference to the receiver object (this).The
eqmethod implements an equivalence relation on non-null instances ofAnyRef, and has three additional properties:- It is consistent: for any non-null instances
xandyof typeAnyRef, multiple invocations ofx.eq(y)consistently returnstrueor consistently returnsfalse. - For any non-null instance
xof typeAnyRef,x.eq(null)andnull.eq(x)returnsfalse. null.eq(null)returnstrue.
When overriding the
equalsorhashCodemethods, 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
trueif the argument is a reference to the receiver object;falseotherwise.
- Definition Classes
- AnyRef
- It is consistent: for any non-null instances
- def equals(arg0: AnyRef): Boolean
The equality method for reference types.
- def exists(p: (A) => Boolean): Boolean
Tests whether a predicate holds for at least one element of this view.
Tests whether a predicate holds for at least one element of this view.
Note: may not terminate for infinite-sized collections.
- p
the predicate used to test elements.
- returns
trueif the given predicatepis satisfied by at least one element of this view, otherwisefalse
- Definition Classes
- IterableOnceOps
- def filter(pred: (A) => Boolean): View[A]
Selects all elements of this view which satisfy a predicate.
Selects all elements of this view which satisfy a predicate.
- returns
a new view consisting of all elements of this view 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 view which do not satisfy a predicate.
Selects all elements of this view which do not satisfy a predicate.
- pred
the predicate used to test elements.
- returns
a new view consisting of all elements of this view 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.
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
finalizemethod is invoked, as well as the interaction betweenfinalizeand non-local returns and exceptions, are all platform dependent.- Attributes
- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.Throwable])
- Note
not specified by SLS as a member of AnyRef
- def find(p: (A) => Boolean): Option[A]
Finds the first element of the view satisfying a predicate, if any.
Finds the first element of the view 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 view that satisfies
p, orNoneif none exists.
- Definition Classes
- IterableOnceOps
- def flatMap[B](f: (A) => IterableOnce[B]): View[B]
Builds a new view by applying a function to all elements of this view and using the elements of the resulting collections.
Builds a new view by applying a function to all elements of this view 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 view. 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 view resulting from applying the given collection-valued function
fto each element of this view and concatenating the results.
- Definition Classes
- IterableOps → IterableOnceOps
- def flatten[B](implicit asIterable: (A) => IterableOnce[B]): View[B]
Converts this view of traversable collections into a view formed by the elements of these traversable collections.
Converts this view of traversable collections into a view formed by the elements of these traversable collections.
The resulting collection's type will be guided by the type of view. 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 view is a
GenTraversable.- returns
a new view resulting from concatenating all element views.
- Definition Classes
- IterableOps → IterableOnceOps
- def fold[A1 >: A](z: A1)(op: (A1, A1) => A1): A1
Folds the elements of this view using the specified associative binary operator.
Folds the elements of this view using the specified associative binary operator. The default implementation in
IterableOnceis equivalent tofoldLeftbut 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.,
Nilfor 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
opbetween all the elements andz, orzif this view 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 view, going left to right.
Applies a binary operator to a start value and all elements of this view, 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
opbetween consecutive elements of this view, going left to right with the start valuezon the left:op(...op(z, x1), x2, ..., xn)wherex1, ..., xnare the elements of this view. Returnszif this view is empty.
- Definition Classes
- IterableOnceOps
- def foldRight[B](z: B)(op: (A, B) => B): B
Applies a binary operator to all elements of this view and a start value, going right to left.
Applies a binary operator to all elements of this view 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
opbetween consecutive elements of this view, going right to left with the start valuezon the right:op(x1, op(x2, ... op(xn, z)...))wherex1, ..., xnare the elements of this view. Returnszif this view is empty.
- Definition Classes
- IterableOnceOps
- def forall(p: (A) => Boolean): Boolean
Tests whether a predicate holds for all elements of this view.
Tests whether a predicate holds for all elements of this view.
Note: may not terminate for infinite-sized collections.
- p
the predicate used to test elements.
- returns
trueif this view is empty or the given predicatepholds for all elements of this view, otherwisefalse.
- Definition Classes
- IterableOnceOps
- def foreach[U](f: (A) => U): Unit
Apply
fto each element for its side effects Note: [U] parameter needed to help scalac's type inference.Apply
fto each element for its side effects Note: [U] parameter needed to help scalac's type inference.- Definition Classes
- IterableOnceOps
- def fromSpecific(coll: IterableOnce[A]): View[A]
Defines how to turn a given
Iterable[A]into a collection of typeC.Defines how to turn a given
Iterable[A]into a collection of typeC.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
,Cto 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 scala.collection.IterableFactoryDefaults trait, which implements the method using iterableFactory.As witnessed by the
@uncheckedVarianceannotation, using this method might be unsound. However, as long as it is called with anIterable[A]obtained fromthiscollection (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.
- def groupBy[K](f: (A) => K): immutable.Map[K, View[A]]
Partitions this view into a map of views according to some discriminator function.
Partitions this view into a map of views 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 views such that the following invariant holds:
(xs groupBy f)(k) = xs filter (x => f(x) == k)That is, every key
kis bound to a view of those elementsxfor whichf(x)equalsk.
- Definition Classes
- IterableOps
- def groupMap[K, B](key: (A) => K)(f: (A) => B): immutable.Map[K, View[B]]
Partitions this view into a map of views according to a discriminator function
key.Partitions this view into a map of views according to a discriminator function
key. Each element in a group is transformed into a value of typeBusing thevaluefunction.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 view into a map according to a discriminator function
key.Partitions this view into a map according to a discriminator function
key. All the values that have the same discriminator are then transformed by theffunction and then reduced into a single value with thereducefunction.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 views.
Partitions elements in fixed size views.
- size
the number of elements per group
- returns
An iterator producing views of size
size, except the last will be less than sizesizeif 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.
- def head: A
Selects the first element of this view.
Selects the first element of this view.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- returns
the first element of this view.
- Definition Classes
- IterableOps
- Exceptions thrown
NoSuchElementExceptionif the view is empty.
- def headOption: Option[A]
Optionally selects the first element.
Optionally selects the first element.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- returns
the first element of this view if it is nonempty,
Noneif it is empty.
- Definition Classes
- IterableOps
- def init: View[A]
The initial part of the collection without its last element.
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 view.
Iterates over the inits of this view. The first value will be this view and the final one will be an empty view, 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 view
- Definition Classes
- IterableOps
List(1,2,3).inits = Iterator(List(1,2,3), List(1,2), List(1), Nil)
Example: - def isEmpty: Boolean
Tests whether the view is empty.
Tests whether the view is empty.
Note: Implementations in subclasses that are not repeatedly traversable must take care not to consume any elements when
isEmptyis called.- returns
trueif the view contains no elements,falseotherwise.
- Definition Classes
- IterableOnceOps
- final def isInstanceOf[T0]: Boolean
Test whether the dynamic type of the receiver object has the same erasure as
T0.Test whether the dynamic type of the receiver object has the same erasure as
T0.Depending on what
T0is, the test is done in one of the below ways:T0is a non-parameterized class type, e.g.BigDecimal: this method returnstrueif the value of the receiver object is aBigDecimalor a subtype ofBigDecimal.T0is a parameterized class type, e.g.List[Int]: this method returnstrueif the value of the receiver object is someList[X]for anyX. For example,List(1, 2, 3).isInstanceOf[List[String]]will return true.T0is some singleton typex.typeor literalx: this method returnsthis.eq(x). For example,x.isInstanceOf[1]is equivalent tox.eq(1)T0is an intersectionX with YorX & Y: this method is equivalent tox.isInstanceOf[X] && x.isInstanceOf[Y]T0is a unionX | Y: this method is equivalent tox.isInstanceOf[X] || x.isInstanceOf[Y]T0is a type parameter or an abstract type member: this method is equivalent toisInstanceOf[U]whereUisT0's upper bound,AnyifT0is unbounded. For example,x.isInstanceOf[A]whereAis an unbounded type parameter will return true for any value ofx.
This is exactly equivalent to the type pattern
_: T0- returns
trueif the receiver object is an instance of erasure of typeT0;falseotherwise.
- Definition Classes
- Any
- Note
due to the unexpectedness of
List(1, 2, 3).isInstanceOf[List[String]]returning true andx.isInstanceOf[A]whereAis a type parameter or abstract member returning true, these forms issue a warning.
- def isTraversableAgain: Boolean
Tests whether this view can be repeatedly traversed.
Tests whether this view can be repeatedly traversed. Always true for Iterables and false for Iterators unless overridden.
- returns
trueif it is repeatedly traversable,falseotherwise.
- Definition Classes
- IterableOps → IterableOnceOps
- def iterableFactory: IterableFactory[View]
The companion object of this view, providing various factory methods.
The companion object of this view, providing various factory methods.
- Definition Classes
- View → Iterable → IterableOps
- Note
When implementing a custom collection type and refining
CCto 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
Iterator can be used only once
- Definition Classes
- Unfold → IterableOnce
- def knownSize: Int
- returns
The number of elements in this view, if it can be cheaply computed, -1 otherwise. Cheaply usually means: Not requiring a collection traversal.
- Definition Classes
- IterableOnce
- def last: A
Selects the last element.
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 view.
- Definition Classes
- IterableOps
- Exceptions thrown
NoSuchElementExceptionIf the view is empty.
- def lastOption: Option[A]
Optionally selects the last element.
Optionally selects the last element.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- returns
the last element of this view$ if it is nonempty,
Noneif it is empty.
- Definition Classes
- IterableOps
- def lazyZip[B](that: Iterable[B]): LazyZip2[A, B, Unfold.this.type]
Analogous to
zipexcept that the elements in each collection are not consumed until a strict operation is invoked on the returnedLazyZip2decorator.Analogous to
zipexcept that the elements in each collection are not consumed until a strict operation is invoked on the returnedLazyZip2decorator.Calls to
lazyZipcan 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
LazyZip2that 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 map[B](f: (A) => B): View[B]
Builds a new view by applying a function to all elements of this view.
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
fto each element of this view and collecting the results.
- Definition Classes
- IterableOps → IterableOnceOps
- def max[B >: A](implicit ord: math.Ordering[B]): A
Finds the largest element.
Finds the largest element.
Note: will not terminate for infinite-sized collections.
- B
The type over which the ordering is defined.
- ord
An ordering to be used for comparing elements.
- returns
the largest element of this view with respect to the ordering
ord.
- Definition Classes
- IterableOnceOps
- Exceptions thrown
UnsupportedOperationExceptionif this view 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.
Finds the first element which yields the largest value measured by function f.
Note: will not terminate for infinite-sized collections.
- 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 view with the largest value measured by function f with respect to the ordering
cmp.
- Definition Classes
- IterableOnceOps
- Exceptions thrown
UnsupportedOperationExceptionif this view 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.
Finds the first element which yields the largest value measured by function f.
Note: will not terminate for infinite-sized collections.
- 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 view 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.
Finds the largest element.
Note: will not terminate for infinite-sized collections.
- 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 view with respect to the ordering
ord.
- Definition Classes
- IterableOnceOps
- def min[B >: A](implicit ord: math.Ordering[B]): A
Finds the smallest element.
Finds the smallest element.
Note: will not terminate for infinite-sized collections.
- B
The type over which the ordering is defined.
- ord
An ordering to be used for comparing elements.
- returns
the smallest element of this view with respect to the ordering
ord.
- Definition Classes
- IterableOnceOps
- Exceptions thrown
UnsupportedOperationExceptionif this view 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.
Finds the first element which yields the smallest value measured by function f.
Note: will not terminate for infinite-sized collections.
- 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 view with the smallest value measured by function f with respect to the ordering
cmp.
- Definition Classes
- IterableOnceOps
- Exceptions thrown
UnsupportedOperationExceptionif this view 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.
Finds the first element which yields the smallest value measured by function f.
Note: will not terminate for infinite-sized collections.
- 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 view 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.
Finds the smallest element.
Note: will not terminate for infinite-sized collections.
- 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 view with respect to the ordering
ord.
- Definition Classes
- IterableOnceOps
- final def mkString: String
Displays all elements of this view in a string.
Displays all elements of this view in a string.
Delegates to addString, which can be overridden.
- returns
a string representation of this view. In the resulting string the string representations (w.r.t. the method
toString) of all elements of this view follow each other without any separator string.
- Definition Classes
- IterableOnceOps
- Annotations
- @inline()
- final def mkString(sep: String): String
Displays all elements of this view in a string using a separator string.
Displays all elements of this view in a string using a separator string.
Delegates to addString, which can be overridden.
- sep
the separator string.
- returns
a string representation of this view. In the resulting string the string representations (w.r.t. the method
toString) of all elements of this view are separated by the stringsep.
- Definition Classes
- IterableOnceOps
- Annotations
- @inline()
List(1, 2, 3).mkString("|") = "1|2|3"
Example: - final def mkString(start: String, sep: String, end: String): String
Displays all elements of this view in a string using start, end, and separator strings.
Displays all elements of this view 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 view. The resulting string begins with the string
startand ends with the stringend. Inside, the string representations (w.r.t. the methodtoString) of all elements of this view are separated by the stringsep.
- Definition Classes
- IterableOnceOps
List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"
Example: - final def ne(arg0: AnyRef): Boolean
Equivalent to
!(this eq that).Equivalent to
!(this eq that).- returns
trueif the argument is not a reference to the receiver object;falseotherwise.
- 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. scala.collection.View or scala.collection.immutable.LazyList), it is possible to implement this method but the resulting
Builderwill break laziness. As a consequence, operations should preferably be implemented withfromSpecificinstead of this method.
- Attributes
- protected
- Definition Classes
- IterableFactoryDefaults → IterableOps
- Note
When implementing a custom collection type and refining
,Cto 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 scala.collection.IterableFactoryDefaults trait, which implements the method using iterableFactory.As witnessed by the
@uncheckedVarianceannotation, using this method might be unsound. However, as long as the returned builder is only fed withAvalues taken fromthisinstance, it is safe.
- def nonEmpty: Boolean
Tests whether the view is not empty.
Tests whether the view is not empty.
- returns
trueif the view contains at least one element,falseotherwise.
- Definition Classes
- IterableOnceOps
- Annotations
- @deprecatedOverriding()
- final def notify(): Unit
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.
- 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.
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 partition(p: (A) => Boolean): (View[A], View[A])
A pair of, first, all elements that satisfy predicate
pand, second, all elements that do not.A pair of, first, all elements that satisfy predicate
pand, 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
partitioninStrictOptimizedIterableOps, 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
fto each element of the view and returns a pair of views: the first one made of those values returned byfthat were wrapped in scala.util.Left, and the second one made of those wrapped in scala.util.Right.Applies a function
fto each element of the view and returns a pair of views: the first one made of those values returned byfthat were wrapped in scala.util.Left, and the second one made of those wrapped in scala.util.Right.Example:
val xs = `View`(1, "one", 2, "two", 3, "three") partitionMap { case i: Int => Left(i) case s: String => Right(s) } // xs == (`View`(1, 2, 3), // `View`(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 view to an scala.util.Either
- returns
a pair of views: the first one made of those values returned by
fthat were wrapped in scala.util.Left, and the second one made of those wrapped in scala.util.Right.
- Definition Classes
- IterableOps
- def product[B >: A](implicit num: math.Numeric[B]): B
Multiplies up the elements of this collection.
Multiplies up the elements of this collection.
Note: will not terminate for infinite-sized collections.
- 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 view with respect to the
*operator innum.
- Definition Classes
- IterableOnceOps
- def reduce[B >: A](op: (B, B) => B): B
Reduces the elements of this view using the specified associative binary operator.
Reduces the elements of this view 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
opbetween all the elements if the view is nonempty.
- Definition Classes
- IterableOnceOps
- Exceptions thrown
UnsupportedOperationExceptionif this view is empty.
- def reduceLeft[B >: A](op: (B, A) => B): B
Applies a binary operator to all elements of this view, going left to right.
Applies a binary operator to all elements of this view, 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
opbetween consecutive elements of this view, going left to right:op( op( ... op(x1, x2) ..., xn-1), xn)wherex1, ..., xnare the elements of this view.
- Definition Classes
- IterableOnceOps
- Exceptions thrown
UnsupportedOperationExceptionif this view is empty.
- def reduceLeftOption[B >: A](op: (B, A) => B): Option[B]
Optionally applies a binary operator to all elements of this view, going left to right.
Optionally applies a binary operator to all elements of this view, 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 view is nonempty,Noneotherwise.
- Definition Classes
- IterableOnceOps
- def reduceOption[B >: A](op: (B, B) => B): Option[B]
Reduces the elements of this view, if any, using the specified associative binary operator.
Reduces the elements of this view, 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
opbetween all the elements if the collection is nonempty, andNoneotherwise.
- Definition Classes
- IterableOnceOps
- def reduceRight[B >: A](op: (A, B) => B): B
Applies a binary operator to all elements of this view, going right to left.
Applies a binary operator to all elements of this view, 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
opbetween consecutive elements of this view, going right to left:op(x1, op(x2, ..., op(xn-1, xn)...))wherex1, ..., xnare the elements of this view.
- Definition Classes
- IterableOnceOps
- Exceptions thrown
UnsupportedOperationExceptionif this view is empty.
- def reduceRightOption[B >: A](op: (A, B) => B): Option[B]
Optionally applies a binary operator to all elements of this view, going right to left.
Optionally applies a binary operator to all elements of this view, 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 view is nonempty,Noneotherwise.
- Definition Classes
- IterableOnceOps
- def reversed: Iterable[A]
- Attributes
- protected
- Definition Classes
- IterableOnceOps
- def scan[B >: A](z: B)(op: (B, B) => B): View[B]
Computes a prefix scan of the elements of the collection.
Computes a prefix scan of the elements of the collection.
Note: The neutral element
zmay 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 view containing the prefix scan of the elements in this view
- Definition Classes
- IterableOps
- def scanLeft[B](z: B)(op: (B, A) => B): View[B]
Produces a view containing cumulative results of applying the operator going left to right, including the initial value.
Produces a view 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
- 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.
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 size: Int
The size of this view.
The size of this view.
Note: will not terminate for infinite-sized collections.
- returns
the number of elements in this view.
- Definition Classes
- IterableOnceOps
- def sizeCompare(that: Iterable[_]): Int
Compares the size of this view to the size of another
Iterable.Compares the size of this view to the size of another
Iterable.- that
the
Iterablewhose size is compared with this view's size.- returns
A value
xwherex < 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
sizedirectly; its running time isO(this.size min that.size)instead ofO(this.size + that.size). The method should be overridden if computingsizeis cheap andknownSizereturns-1.
- Definition Classes
- IterableOps
- def sizeCompare(otherSize: Int): Int
Compares the size of this view to a test value.
Compares the size of this view to a test value.
- otherSize
the test value that gets compared with the size.
- returns
A value
xwherex < 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
sizedirectly; its running time isO(size min otherSize)instead ofO(size). The method should be overridden if computingsizeis cheap andknownSizereturns-1.
- Definition Classes
- IterableOps
- See also
- final def sizeIs: SizeCompareOps
Returns a value class containing operations for comparing the size of this view to a test value.
Returns a value class containing operations for comparing the size of this view 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.
Selects an interval of elements. The returned view is made up of all elements
xwhich 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 view.
- until
the lowest index to EXCLUDE from this view.
- returns
a view containing the elements greater than or equal to index
fromextending up to (but not including) indexuntilof this view.
- Definition Classes
- IterableOps → IterableOnceOps
- 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.)
Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.)
The returned iterator will be empty when called on an empty collection. The last element the iterator produces may be smaller than the window size when the original collection isn't exhausted by the window before it and its last element isn't skipped by the step before it.
- size
the number of elements per group
- step
the distance between the first elements of successive groups
- returns
An iterator producing views of size
size, except the last element (which may be the only element) will be smaller if there are fewer thansizeelements remaining to be grouped.
- Definition Classes
- IterableOps
List(1, 2, 3, 4, 5).sliding(2, 2) = Iterator(List(1, 2), List(3, 4), List(5)), List(1, 2, 3, 4, 5, 6).sliding(2, 3) = Iterator(List(1, 2), List(4, 5))- See also
scala.collection.Iterator, method
sliding
Examples: - 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.)Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in
grouped.)An empty collection returns an empty iterator, and a non-empty collection containing fewer elements than the window size returns an iterator that will produce the original collection as its only element.
- size
the number of elements per group
- returns
An iterator producing views of size
size, except for a non-empty collection with less thansizeelements, which returns an iterator that produces the source collection itself as its only element.
- Definition Classes
- IterableOps
List().sliding(2) = empty iterator, List(1).sliding(2) = Iterator(List(1)), List(1, 2).sliding(2) = Iterator(List(1, 2)), List(1, 2, 3).sliding(2) = Iterator(List(1, 2), List(2, 3))- See also
scala.collection.Iterator, method
sliding
Examples: - def span(p: (A) => Boolean): (View[A], View[A])
Splits this view into a prefix/suffix pair according to a predicate.
Splits this view into a prefix/suffix pair according to a predicate.
Note:
c span pis equivalent to (but possibly more efficient than)(c takeWhile p, c dropWhile p), provided the evaluation of the predicatepdoes 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 view whose elements all satisfy
p, and the rest of this view.
- Definition Classes
- IterableOps → IterableOnceOps
- def splitAt(n: Int): (View[A], View[A])
Splits this view into a prefix/suffix pair at a given position.
Splits this view into a prefix/suffix pair at a given position.
Note:
c splitAt nis 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 views consisting of the first
nelements of this view, and the other elements.
- Definition Classes
- IterableOps → IterableOnceOps
- def stepper[S <: Stepper[_]](implicit shape: StepperShape[A, S]): S
Returns a scala.collection.Stepper for the elements of this collection.
Returns a scala.collection.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 scala.collection.StepperShape parameter defines the resulting Stepper type according to the element type of this collection.
- For collections of
Int,Short,ByteorChar, an scala.collection.IntStepper is returned - For collections of
DoubleorFloat, a scala.collection.DoubleStepper is returned - For collections of
Longa scala.collection.LongStepper is returned - For any other element type, an scala.collection.AnyStepper is returned
Note that this method is overridden in subclasses and the return type is refined to
S with EfficientSplit, for example scala.collection.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
- For collections of
- def stringPrefix: String
- def sum[B >: A](implicit num: math.Numeric[B]): B
Sums up the elements of this collection.
Sums up the elements of this collection.
Note: will not terminate for infinite-sized collections.
- 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 view with respect to the
+operator innum.
- Definition Classes
- IterableOnceOps
- final def synchronized[T0](arg0: => T0): T0
Executes the code in
bodywith an exclusive lock onthis.Executes the code in
bodywith an exclusive lock onthis.- returns
the result of
body
- Definition Classes
- AnyRef
- def tail: View[A]
The rest of the collection without its first element.
The rest of the collection without its first element.
- Definition Classes
- IterableOps
- def tails: Iterator[View[A]]
Iterates over the tails of this view.
Iterates over the tails of this view. The first value will be this view and the final one will be an empty view, with the intervening values the results of successive applications of
tail.- returns
an iterator over all the tails of this view
- Definition Classes
- IterableOps
List(1,2,3).tails = Iterator(List(1,2,3), List(2,3), List(3), Nil)
Example: - def take(n: Int): View[A]
Selects the first n elements.
Selects the first n elements.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- n
the number of elements to take from this view.
- returns
a view consisting only of the first
nelements of this view, or else the whole view, if it has less thannelements. Ifnis negative, returns an empty view.
- Definition Classes
- IterableOps → IterableOnceOps
- def takeRight(n: Int): View[A]
Selects the last n elements.
Selects the last n elements.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- n
the number of elements to take from this view.
- returns
a view consisting only of the last
nelements of this view, or else the whole view, if it has less thannelements. Ifnis negative, returns an empty view.
- Definition Classes
- IterableOps
- def takeWhile(p: (A) => Boolean): View[A]
Takes longest prefix of elements that satisfy a predicate.
Takes longest prefix of elements that satisfy a predicate.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- p
The predicate used to test elements.
- returns
the longest prefix of this view whose elements all satisfy the predicate
p.
- Definition Classes
- IterableOps → IterableOnceOps
- def tapEach[U](f: (A) => U): View[A]
Applies a side-effecting function to each element in this collection.
Applies a side-effecting function to each element in this collection. Strict collections will apply
fto their elements immediately, while lazy collections like Views and LazyLists will only applyfon 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
- 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 typeA.Given a collection factory
factory, convert this collection to the appropriate representation for the current element typeA. 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.
Convert collection to array.
Implementation note: DO NOT call Array.from from this method.
- Definition Classes
- IterableOnceOps
- final def toBuffer[B >: A]: Buffer[B]
- Definition Classes
- IterableOnceOps
- Annotations
- @inline()
- def toIndexedSeq: immutable.IndexedSeq[A]
- Definition Classes
- IterableOnceOps
- 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.
- def toVector: immutable.Vector[A]
- Definition Classes
- IterableOnceOps
- def transpose[B](implicit asIterable: (A) => Iterable[B]): View[View[B]]
Transposes this view of iterable collections into a view of views.
Transposes this view of iterable collections into a view of views.
The resulting collection's type will be guided by the static type of view. 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 view is an
Iterable.- returns
a two-dimensional view of views which has as nth row the nth column of this view.
- Definition Classes
- IterableOps
- Exceptions thrown
IllegalArgumentExceptionif all collections in this view are not of the same size.
- def unzip[A1, A2](implicit asPair: (A) => (A1, A2)): (View[A1], View[A2])
Converts this view of pairs into two collections of the first and second half of each pair.
Converts this view of pairs into two collections of the first and second half of each pair.
val xs = `View`( (1, "one"), (2, "two"), (3, "three")).unzip // xs == (`View`(1, 2, 3), // `View`(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 view is a pair.
- returns
a pair of views, containing the first, respectively second half of each element pair of this view.
- Definition Classes
- IterableOps
- def unzip3[A1, A2, A3](implicit asTriple: (A) => (A1, A2, A3)): (View[A1], View[A2], View[A3])
Converts this view of triples into three collections of the first, second, and third element of each triple.
Converts this view of triples into three collections of the first, second, and third element of each triple.
val xs = `View`( (1, "one", '1'), (2, "two", '2'), (3, "three", '3')).unzip3 // xs == (`View`(1, 2, 3), // `View`(one, two, three), // `View`(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 view is a triple.
- returns
a triple of views, containing the first, second, respectively third member of each element triple of this view.
- Definition Classes
- IterableOps
- def view: View[A]
A view over the elements of this collection.
A view over the elements of this collection.
- Definition Classes
- View → IterableOps
- final def wait(): Unit
See https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#wait--.
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
- Note
not specified by SLS as a member of AnyRef
- final def wait(arg0: Long, arg1: Int): Unit
See https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#wait-long-int-
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
- Note
not specified by SLS as a member of AnyRef
- final def wait(arg0: Long): Unit
See https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#wait-long-.
- def withFilter(p: (A) => Boolean): WithFilter[A, [_]View[_]]
Creates a non-strict filter of this view.
Creates a non-strict filter of this view.
Note: the difference between
c filter pandc withFilter pis that the former creates a new collection, whereas the latter only restricts the domain of subsequentmap,flatMap,foreach, andwithFilteroperations.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, andwithFilteroperations. All these operations apply to those elements of this view which satisfy the predicatep.
- Definition Classes
- IterableOps
- def zip[B](that: IterableOnce[B]): View[(A, B)]
Returns a view formed from this view and another iterable collection by combining corresponding elements in pairs.
Returns a view formed from this view 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 view containing pairs consisting of corresponding elements of this view and
that. The length of the returned collection is the minimum of the lengths of this view andthat.
- Definition Classes
- IterableOps
- def zipAll[A1 >: A, B](that: Iterable[B], thisElem: A1, thatElem: B): View[(A1, B)]
Returns a view formed from this view and another iterable collection by combining corresponding elements in pairs.
Returns a view formed from this view 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 view is shorter than
that.- thatElem
the element to be used to fill up the result if
thatis shorter than this view.- returns
a new collection of type
Thatcontaining pairs consisting of corresponding elements of this view andthat. The length of the returned collection is the maximum of the lengths of this view andthat. If this view is shorter thanthat,thisElemvalues are used to pad the result. Ifthatis shorter than this view,thatElemvalues are used to pad the result.
- Definition Classes
- IterableOps
- def zipWithIndex: View[(A, Int)]
Zips this view with its indices.
Zips this view with its indices.
- returns
A new view containing pairs consisting of all elements of this view paired with their index. Indices start at
0.
- Definition Classes
- IterableOps → IterableOnceOps
List("a", "b", "c").zipWithIndex == List(("a", 0), ("b", 1), ("c", 2))
Example:
Deprecated Value Members
- def ++:[B >: A](that: IterableOnce[B]): View[B]
- Definition Classes
- IterableOps
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use ++ instead of ++: for collections of type Iterable
- def /:[B](z: B)(op: (B, A) => B): B
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
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- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator.foldLeft instead
- final def /:[B](z: B)(op: (B, A) => B): B
- Definition Classes
- IterableOnceOps
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use foldLeft instead of /:
- def :\[B](z: B)(op: (A, B) => B): B
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
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- Definition Classes
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- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator.foldRight instead
- final def :\[B](z: B)(op: (A, B) => B): B
- Definition Classes
- IterableOnceOps
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use foldRight instead of :\
- def aggregate[B](z: => B)(seqop: (B, A) => B, combop: (B, B) => B): B
- Definition Classes
- IterableOnceOps
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0)
aggregateis not relevant for sequential collections. UsefoldLeft(z)(seqop)instead.
- def collectFirst[B](f: PartialFunction[A, B]): Option[B]
- Implicit
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- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.collectFirst(...) instead
- def companion: IterableFactory[[_]View[_]]
- Definition Classes
- IterableOps
- Annotations
- @deprecated @deprecatedOverriding() @inline()
- Deprecated
(Since version 2.13.0) Use iterableFactory instead
- def copyToBuffer(dest: Buffer[A]): Unit
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
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- Definition Classes
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- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.copyToBuffer(...) instead
- final def copyToBuffer[B >: A](dest: Buffer[B]): Unit
- Definition Classes
- IterableOnceOps
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use
dest ++= collinstead
- def count(f: (A) => Boolean): Int
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
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- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.count(...) instead
- def exists(f: (A) => Boolean): Boolean
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
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- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.exists(...) instead
- def filter(f: (A) => Boolean): Iterator[A]
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
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- Definition Classes
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- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.filter(...) instead
- def find(p: (A) => Boolean): Option[A]
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
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- Definition Classes
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- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.find instead
- def flatMap[B](f: (A) => IterableOnce[B]): IterableOnce[B]
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- Definition Classes
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- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.flatMap instead or consider requiring an Iterable
- def fold[A1 >: A](z: A1)(op: (A1, A1) => A1): A1
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
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- Definition Classes
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- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.fold instead
- def foldLeft[B](z: B)(op: (B, A) => B): B
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
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- Definition Classes
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- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator.foldLeft instead
- def foldRight[B](z: B)(op: (A, B) => B): B
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
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- Definition Classes
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- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator.foldRight instead
- def forall(f: (A) => Boolean): Boolean
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
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- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.forall(...) instead
- def force: IndexedSeq[A]
- Definition Classes
- View
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Views no longer know about their underlying collection type; .force always returns an IndexedSeq
- def foreach[U](f: (A) => U): Unit
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
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- Definition Classes
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- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator.foreach(...) instead
- def formatted(fmtstr: String): String
Returns string formatted according to given
formatstring.Returns string formatted according to given
formatstring. Format strings are as forString.format(@see java.lang.String.format).- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toStringFormat[Unfold[A, S]] performed by method StringFormat in scala.Predef.
- Definition Classes
- StringFormat
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.12.16) Use
formatString.format(value)instead ofvalue.formatted(formatString), or use thef""string interpolator. In Java 15 and later,formattedresolves to the new method in String which has reversed parameters.
- def hasDefiniteSize: Boolean
Tests whether this view is known to have a finite size.
Tests whether this view 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 returnstrueif all elements have been computed. It returnsfalseif the stream is not yet evaluated to the end. Non-empty Iterators usually returnfalseeven if they were created from a collection with a known finite size.Note: many collection methods will not work on collections of infinite sizes. The typical failure mode is an infinite loop. These methods always attempt a traversal without checking first that
hasDefiniteSizereturnstrue. However, checkinghasDefiniteSizecan provide an assurance that size is well-defined and non-termination is not a concern.- returns
trueif this collection is known to have finite size,falseotherwise.
- Definition Classes
- IterableOnceOps
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Check .knownSize instead of .hasDefiniteSize for more actionable information (see scaladoc for details)
- See also
method
knownSizefor a more useful alternative
- def isEmpty: Boolean
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
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- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.isEmpty instead
- def map[B](f: (A) => B): IterableOnce[B]
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
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- Definition Classes
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- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.map instead or consider requiring an Iterable
- def max(implicit ord: math.Ordering[A]): A
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
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- Definition Classes
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- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.max instead
- def maxBy[B](f: (A) => B)(implicit cmp: math.Ordering[B]): A
- Implicit
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- Definition Classes
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- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.maxBy(...) instead
- def min(implicit ord: math.Ordering[A]): A
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
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- Definition Classes
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- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.min instead
- def minBy[B](f: (A) => B)(implicit cmp: math.Ordering[B]): A
- Implicit
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- Definition Classes
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- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.minBy(...) instead
- def mkString: String
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
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- Definition Classes
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(Since version 2.13.0) Use .iterator.mkString instead
- def mkString(sep: String): String
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- Definition Classes
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(Since version 2.13.0) Use .iterator.mkString instead
- def mkString(start: String, sep: String, end: String): String
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- Definition Classes
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- def nonEmpty: Boolean
- Implicit
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- Definition Classes
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- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.nonEmpty instead
- def product(implicit num: math.Numeric[A]): A
- Implicit
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- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(unfold: IterableOnceExtensionMethods[A]).product(num)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.product instead
- def reduce(f: (A, A) => A): A
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(unfold: IterableOnceExtensionMethods[A]).reduce(f)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.reduce(...) instead
- def reduceLeft(f: (A, A) => A): A
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(unfold: IterableOnceExtensionMethods[A]).reduceLeft(f)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.reduceLeft(...) instead
- def reduceLeftOption(f: (A, A) => A): Option[A]
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(unfold: IterableOnceExtensionMethods[A]).reduceLeftOption(f)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.reduceLeftOption(...) instead
- def reduceOption(f: (A, A) => A): Option[A]
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(unfold: IterableOnceExtensionMethods[A]).reduceOption(f)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.reduceOption(...) instead
- def reduceRight(f: (A, A) => A): A
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(unfold: IterableOnceExtensionMethods[A]).reduceRight(f)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.reduceRight(...) instead
- def reduceRightOption(f: (A, A) => A): Option[A]
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(unfold: IterableOnceExtensionMethods[A]).reduceRightOption(f)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.reduceRightOption(...) instead
- final def repr: View[A]
- Definition Classes
- IterableOps
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use coll instead of repr in a collection implementation, use the collection value itself from the outside
- def sameElements[B >: A](that: IterableOnce[B]): Boolean
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.sameElements instead
- def seq: Unfold.this.type
- Definition Classes
- Iterable
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Iterable.seq always returns the iterable itself
- def size: Int
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
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- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.size instead
- def sum(implicit num: math.Numeric[A]): A
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(unfold: IterableOnceExtensionMethods[A]).sum(num)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.sum instead
- def to[C1](factory: Factory[A, C1]): C1
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(unfold: IterableOnceExtensionMethods[A]).to(factory)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.to(factory) instead
- def toArray[B >: A](implicit arg0: ClassTag[B]): Array[B]
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(unfold: IterableOnceExtensionMethods[A]).toArray(arg0)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.toArray
- def toBuffer[B >: A]: Buffer[B]
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(unfold: IterableOnceExtensionMethods[A]).toBuffer
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.to(ArrayBuffer) instead
- def toIndexedSeq: IndexedSeq[A]
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(unfold: IterableOnceExtensionMethods[A]).toIndexedSeq
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.toIndexedSeq instead
- final def toIterable: Iterable[A]
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(unfold: IterableOnceExtensionMethods[A]).toIterable
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator.to(Iterable) instead
- final def toIterable: Unfold.this.type
- returns
This collection as an
Iterable[A]. No new collection will be built ifthisis already anIterable[A].
- Definition Classes
- Iterable → IterableOps
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.7) toIterable is internal and will be made protected; its name is similar to
toListortoSeq, but it doesn't copy non-immutable collections
- def toIterator: Iterator[A]
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(unfold: IterableOnceExtensionMethods[A]).toIterator
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator instead
- final def toIterator: Iterator[A]
- Definition Classes
- IterableOnceOps
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator instead of .toIterator
- def toList: immutable.List[A]
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(unfold: IterableOnceExtensionMethods[A]).toList
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.to(List) instead
- def toMap[K, V](implicit ev: <:<[A, (K, V)]): immutable.Map[K, V]
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(unfold: IterableOnceExtensionMethods[A]).toMap(ev)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.to(Map) instead
- def toSeq: immutable.Seq[A]
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(unfold: IterableOnceExtensionMethods[A]).toSeq
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator.to(Seq) instead
- def toSet[B >: A]: immutable.Set[B]
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(unfold: IterableOnceExtensionMethods[A]).toSet
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator.to(Set) instead
- def toStream: immutable.Stream[A]
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(unfold: IterableOnceExtensionMethods[A]).toStream
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator.to(LazyList) instead
- final def toStream: immutable.Stream[A]
- Definition Classes
- IterableOnceOps
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .to(LazyList) instead of .toStream
- final def toTraversable: Traversable[A]
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
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- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator.to(Iterable) instead
- final def toTraversable: Traversable[A]
Converts this view to an unspecified Iterable.
Converts this view to an unspecified Iterable. Will return the same collection if this instance is already Iterable.
- returns
An Iterable containing all elements of this view.
- Definition Classes
- IterableOps
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) toTraversable is internal and will be made protected; its name is similar to
toListortoSeq, but it doesn't copy non-immutable collections
- def toVector: immutable.Vector[A]
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(unfold: IterableOnceExtensionMethods[A]).toVector
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.13.0) Use .iterator.to(Vector) instead
- def view(from: Int, until: Int): View[A]
A view over a slice of the elements of this collection.
A view over a slice of the elements of this collection.
- Definition Classes
- IterableOps
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .view.slice(from, until) instead of .view(from, until)
- def withFilter(f: (A) => Boolean): Iterator[A]
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toIterableOnceExtensionMethods[A] performed by method iterableOnceExtensionMethods in scala.collection.IterableOnce.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(unfold: IterableOnceExtensionMethods[A]).withFilter(f)
- Definition Classes
- IterableOnceExtensionMethods
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use .iterator.withFilter(...) instead
- def →[B](y: B): (Unfold[A, S], B)
- Implicit
- This member is added by an implicit conversion from Unfold[A, S] toArrowAssoc[Unfold[A, S]] performed by method ArrowAssoc in scala.Predef.
- Definition Classes
- ArrowAssoc
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use
->instead. If you still wish to display it as one character, consider using a font with programming ligatures such as Fira Code.
This is the documentation for the Scala standard library.
Package structure
The scala package contains core types like
Int,Float,ArrayorOptionwhich are accessible in all Scala compilation units without explicit qualification or imports.Notable packages include:
scala.collectionand its sub-packages contain Scala's collections frameworkscala.collection.immutable- Immutable, sequential data-structures such asVector,List,Range,HashMaporHashSetscala.collection.mutable- Mutable, sequential data-structures such asArrayBuffer,StringBuilder,HashMaporHashSetscala.collection.concurrent- Mutable, concurrent data-structures such asTrieMapscala.concurrent- Primitives for concurrent programming such asFuturesandPromisesscala.io- Input and output operationsscala.math- Basic math functions and additional numeric types likeBigIntandBigDecimalscala.sys- Interaction with other processes and the operating systemscala.util.matching- Regular expressionsOther packages exist. See the complete list on the right.
Additional parts of the standard library are shipped as separate libraries. These include:
scala.reflect- Scala's reflection API (scala-reflect.jar)scala.xml- XML parsing, manipulation, and serialization (scala-xml.jar)scala.collection.parallel- Parallel collections (scala-parallel-collections.jar)scala.util.parsing- Parser combinators (scala-parser-combinators.jar)scala.swing- A convenient wrapper around Java's GUI framework called Swing (scala-swing.jar)Automatic imports
Identifiers in the scala package and the
scala.Predefobject are always in scope by default.Some of these identifiers are type aliases provided as shortcuts to commonly used classes. For example,
Listis an alias forscala.collection.immutable.List.Other aliases refer to classes provided by the underlying platform. For example, on the JVM,
Stringis an alias forjava.lang.String.