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Scala 3/scala/Option

Option

scala.Option

See theOption companion object

sealed abstractclassOption[+A] extendsIterableOnce[A],Product,Serializable

Represents optional values. Instances ofOption are either an instance of $some or the object $none.

The most idiomatic way to use an $option instance is to treat it as a collection or monad and usemap,flatMap,filter, orforeach:

val name: Option[String] = request getParameter "name"val upper = name map { _.trim } filter { _.length != 0 } map { _.toUpperCase }println(upper getOrElse "")

Note that this is equivalent to

val upper = for {  name <- request getParameter "name"  trimmed <- Some(name.trim)  upper <- Some(trimmed.toUpperCase) if trimmed.length != 0} yield upperprintln(upper getOrElse "")

Because of how for comprehension works, if $none is returned fromrequest.getParameter, the entire expression results in $none

This allows for sophisticated chaining of $option values without having to check for the existence of a value.

These are useful methods that exist for both $some and $none. -isDefined — True if not empty -isEmpty — True if empty -nonEmpty — True if not empty -orElse — Evaluate and return alternate optional value if empty -getOrElse — Evaluate and return alternate value if empty -get — Return value, throw exception if empty -fold — Apply function on optional value, return default if empty -map — Apply a function on the optional value -flatMap — Same as map but function must return an optional value -foreach — Apply a procedure on option value -collect — Apply partial pattern match on optional value -filter — An optional value satisfies predicate -filterNot — An optional value doesn't satisfy predicate -exists — Apply predicate on optional value, or false if empty -forall — Apply predicate on optional value, or true if empty -contains — Checks if value equals optional value, or false if empty -zip — Combine two optional values to make a paired optional value -unzip — Split an optional pair to two optional values -unzip3 — Split an optional triple to three optional values -toList — Unary list of optional value, otherwise the empty list

A less-idiomatic way to use $option values is via pattern matching:

val nameMaybe = request getParameter "name"nameMaybe match {  case Some(name) =>    println(name.trim.toUppercase)  case None =>    println("No name value")}

Interacting with code that can occasionally return null can be safely wrapped in $option to become $none and $some otherwise.

val abc = new java.util.HashMap[Int, String]abc.put(1, "A")bMaybe = Option(abc.get(2))bMaybe match { case Some(b) =>   println(s"Found $b") case None =>   println("Not found")}

Attributes

Note: Many of the methods in here are duplicative with those in the Iterable hierarchy, but they are duplicated for a reason: the implicit conversion tends to leave one with an Iterable in situations where one could have retained an Option.
Companion: object
Source: Option.scala
Graph
Supertypes: traitSerializable
traitProduct
traitEquals
traitIterableOnce[A]
classObject
traitMatchable
classAny
Show all
Known subtypes: objectNone
classSome[A]
Self type: Option[A]

Members list

Type members

Classlikes

classWithFilter(p:Option.this.A=>Boolean)

We need a whole WithFilter class to honor the "doesn't create a new collection" contract even though it seems unlikely to matter much in a collection with max size 1.

Attributes

Source: Option.scala
Supertypes: classObject
traitMatchable
classAny

Value members

Abstract methods

defget:A

Returns the option's value.

This is equivalent to:

option match { case Some(x) => x case None    => throw new Exception}

Attributes

Throws: NoSuchElementExceptionif the option is empty.
Note: The option must be nonempty.
Source: Option.scala

Concrete methods

finaldefcollect[B](pf:PartialFunction[A,B]):Option[B]

Returns ascala.Some containing the result of applyingpf to thisscala.Option's contained value,if this option is nonemptyandpf is defined for that value.

Returns ascala.Some containing the result of applyingpf to thisscala.Option's contained value,if this option is nonemptyandpf is defined for that value. ReturnsNone otherwise.

Value parameters

pf: the partial function.

Attributes

Returns

the result of applyingpf to thisscala.Option's value (if possible), orNone.

Example

// Returns Some(HTTP) because the partial function covers the case.Some("http") collect {case "http" => "HTTP"}// Returns None because the partial function doesn't cover the case.Some("ftp") collect {case "http" => "HTTP"}// Returns None because the option is empty. There is no value to pass to the partial function.None collect {case value => value}

Source

Option.scala

finaldefcontains[A1 >:A](elem:A1):Boolean

Tests whether the option contains a given value as an element.

This is equivalent to:

option match { case Some(x) => x == elem case None    => false}

Value parameters

elem: the element to test.

Attributes

Returns

true if the option has an element that is equal (as determined by==) toelem,false otherwise.

Example

// Returns true because Some instance contains string "something" which equals "something".Some("something") contains "something"// Returns false because "something" != "anything".Some("something") contains "anything"// Returns false when method called on None.None contains "anything"

Source

Option.scala

finaldefexists(p:A=>Boolean):Boolean

Returns true if this option is nonemptyand the predicatep returns true when applied to thisscala.Option's value.

Returns true if this option is nonemptyand the predicatep returns true when applied to thisscala.Option's value. Otherwise, returns false.

This is equivalent to:

option match { case Some(x) => p(x) case None    => false}

Value parameters

p: the predicate to test

Attributes

Source: Option.scala

finaldeffilter(p:A=>Boolean):Option[A]

Returns thisscala.Option if it is nonemptyand applying the predicatep to thisscala.Option's value returns true.

Returns thisscala.Option if it is nonemptyand applying the predicatep to thisscala.Option's value returns true. Otherwise, returnNone.

This is equivalent to:

option match { case Some(x) if p(x) => Some(x) case _               => None}

Value parameters

p: the predicate used for testing.

Attributes

Source: Option.scala

finaldeffilterNot(p:A=>Boolean):Option[A]

Returns thisscala.Option if it is nonemptyand applying the predicatep to thisscala.Option's value returns false.

Returns thisscala.Option if it is nonemptyand applying the predicatep to thisscala.Option's value returns false. Otherwise, returnNone.

This is equivalent to:

option match { case Some(x) if !p(x) => Some(x) case _                => None}

Value parameters

p: the predicate used for testing.

Attributes

Source: Option.scala

finaldefflatMap[B](f:A=>Option[B]):Option[B]

Returns the result of applyingf to thisscala.Option's value if thisscala.Option is nonempty.

Returns the result of applyingf to thisscala.Option's value if thisscala.Option is nonempty. ReturnsNone if thisscala.Option is empty. Slightly different frommap in thatf is expected to return anscala.Option (which could beNone).

This is equivalent to:

option match { case Some(x) => f(x) case None    => None}

Value parameters

f: the function to apply

Attributes

See also: map
foreach
Source: Option.scala

defflatten[B](implicitev:A<:<Option[B]):Option[B]

Returns the nestedscala.Option value if it is nonempty.

Returns the nestedscala.Option value if it is nonempty. Otherwise, returnNone.

This is equivalent to:

option match { case Some(Some(b)) => Some(b) case _             => None}

Value parameters

ev: an implicit conversion that asserts that the value is also anscala.Option.

Attributes

See also

flatMap

Example

Some(Some("something")).flatten

Source

Option.scala

finaldeffold[B](ifEmpty:=>B)(f:A=>B):B

Returns the result of applyingf to thisscala.Option's value if thescala.Option is nonempty.

Returns the result of applyingf to thisscala.Option's value if thescala.Option is nonempty. Otherwise, evaluates expressionifEmpty.

This is equivalent to:

option match { case Some(x) => f(x) case None    => ifEmpty}

This is also equivalent to:

option map f getOrElse ifEmpty

Value parameters

f: the function to apply if nonempty.
ifEmpty: the expression to evaluate if empty.

Attributes

Source: Option.scala

finaldefforall(p:A=>Boolean):Boolean

Returns true if this option is emptyor the predicatep returns true when applied to thisscala.Option's value.

This is equivalent to:

option match { case Some(x) => p(x) case None    => true}

Value parameters

p: the predicate to test

Attributes

Source: Option.scala

finaldefforeach[U](f:A=>U):Unit

Apply the given proceduref to the option's value, if it is nonempty.

Apply the given proceduref to the option's value, if it is nonempty. Otherwise, do nothing.

This is equivalent to:

option match { case Some(x) => f(x) case None    => ()}

Value parameters

f: the procedure to apply.

Attributes

See also: map
flatMap
Source: Option.scala

finaldefgetOrElse[B >:A](default:=>B):B

Returns the option's value if the option is nonempty, otherwise return the result of evaluatingdefault.

This is equivalent to:

option match { case Some(x) => x case None    => default}

Value parameters

default: the default expression.

Attributes

Source: Option.scala

finaldefisDefined:Boolean

Returns true if the option is an instance ofscala.Some, false otherwise.

This is equivalent to:

option match { case Some(_) => true case None    => false}

Attributes

Source: Option.scala

finaldefisEmpty:Boolean

Returns true if the option isNone, false otherwise.

This is equivalent to:

option match { case Some(_) => false case None    => true}

Attributes

Source: Option.scala

defiterableFactory:IterableFactory[Iterable]

Implicitly added byoption2Iterable

The companion object of this iterable collection, providing various factory methods.

Attributes

Note: When implementing a custom collection type and refiningCC to the new type, this method needs to be overridden to return a factory for the new type (the compiler will issue an error otherwise).
Source: Iterable.scala

defiterator:Iterator[A]

Returns a singleton iterator returning thescala.Option's value if it is nonempty, or an empty iterator if the option is empty.

Attributes

Source: Option.scala

final overridedefknownSize:Int

The number of elements in this option, if it can be cheaply computed, -1 otherwise.

The number of elements in this option, if it can be cheaply computed, -1 otherwise. Cheaply usually means: Not requiring a collection traversal.

Attributes

Definition Classes: IterableOnce
Source: Option.scala

deflazyZip[B](that:Iterable[B]):LazyZip2[A,B,this.type]

Implicitly added byoption2Iterable

Analogous tozip except that the elements in each collection are not consumed until a strict operation is invoked on the returnedLazyZip2 decorator.

Calls tolazyZip can be chained to support higher arities (up to 4) without incurring the expense of constructing and deconstructing intermediary tuples.

val xs = List(1, 2, 3)val res = (xs lazyZip xs lazyZip xs lazyZip xs).map((a, b, c, d) => a + b + c + d)// res == List(4, 8, 12)

Type parameters

B: the type of the second element in each eventual pair

Value parameters

that: the iterable providing the second element of each eventual pair

Attributes

Returns: a decoratorLazyZip2 that allows strict operations to be performed on the lazily evaluated pairs or chained calls tolazyZip. Implicit conversion toIterable[(A, B)] is also supported.
Source: Iterable.scala

finaldefmap[B](f:A=>B):Option[B]

Returns ascala.Some containing the result of applyingf to thisscala.Option's value if thisscala.Option is nonempty.

Returns ascala.Some containing the result of applyingf to thisscala.Option's value if thisscala.Option is nonempty. Otherwise returnNone.

This is equivalent to:

option match { case Some(x) => Some(f(x)) case None    => None}

Value parameters

f: the function to apply

Attributes

See also: flatMap
foreach
Note: This is similar toflatMap except here,f does not need to wrap its result in anscala.Option.
Source: Option.scala

finaldefnonEmpty:Boolean

Returns false if the option isNone, true otherwise.

This is equivalent to:

option match { case Some(_) => true case None    => false}

Attributes

Note: Implemented here to avoid the implicit conversion to Iterable.
Source: Option.scala

finaldeforElse[B >:A](alternative:=>Option[B]):Option[B]

Returns thisscala.Option if it is nonempty, otherwise return the result of evaluatingalternative.

This is equivalent to:

option match { case Some(x) => Some(x) case None    => alternative}

Value parameters

alternative: the alternative expression.

Attributes

Source: Option.scala

finaldeforNull[A1 >:A](implicitev:Null <:<A1):A1

Returns the option's value if it is nonempty, ornull if it is empty.

Although the use of null is discouraged, code written to usescala.Option must often interface with code that expects and returns nulls.

This is equivalent to:

option match { case Some(x) => x case None    => null}

Attributes

Example

val initialText: Option[String] = getInitialTextval textField = new JComponent(initialText.orNull,20)

Source

Option.scala

finaldeftoLeft[X](right:=>X):Either[A,X]

Returns ascala.util.Right containing the given argumentright if this is empty, or ascala.util.Left containing thisscala.Option's value if thisscala.Option is nonempty.

This is equivalent to:

option match { case Some(x) => Left(x) case None    => Right(right)}

Value parameters

right: the expression to evaluate and return if this is empty

Attributes

See also: toRight
Source: Option.scala

deftoList:List[A]

Returns a singleton list containing thescala.Option's value if it is nonempty, or the empty list if thescala.Option is empty.

This is equivalent to:

option match { case Some(x) => List(x) case None    => Nil}

Attributes

Source: Option.scala

finaldeftoRight[X](left:=>X):Either[X,A]

Returns ascala.util.Left containing the given argumentleft if thisscala.Option is empty, or ascala.util.Right containing thisscala.Option's value if this is nonempty.

This is equivalent to:

option match { case Some(x) => Right(x) case None    => Left(left)}

Value parameters

left: the expression to evaluate and return if this is empty

Attributes

See also: toLeft
Source: Option.scala

finaldefunzip[A1,A2](implicitasPair:A<:< (A1,A2)): (Option[A1],Option[A2])

Converts an Option of a pair into an Option of the first element and an Option of the second element.

This is equivalent to:

option match {  case Some((x, y)) => (Some(x), Some(y))  case _            => (None,    None)}

Type parameters

A1: the type of the first half of the element pair
A2: the type of the second half of the element pair

Value parameters

asPair: an implicit conversion which asserts that the element type of this Option is a pair.

Attributes

Returns: a pair of Options, containing, respectively, the first and second half of the element pair of this Option.
Source: Option.scala

finaldefunzip3[A1,A2,A3](implicitasTriple:A<:< (A1,A2,A3)): (Option[A1],Option[A2],Option[A3])

Converts an Option of a triple into three Options, one containing the element from each position of the triple.

This is equivalent to:

option match {  case Some((x, y, z)) => (Some(x), Some(y), Some(z))  case _               => (None,    None,    None)}

Type parameters

A1: the type of the first of three elements in the triple
A2: the type of the second of three elements in the triple
A3: the type of the third of three elements in the triple

Value parameters

asTriple: an implicit conversion which asserts that the element type of this Option is a triple.

Attributes

Returns: a triple of Options, containing, respectively, the first, second, and third elements from the element triple of this Option.
Source: Option.scala

finaldefwithFilter(p:A=>Boolean):WithFilter

Necessary to keepscala.Option from being implicitly converted toscala.collection.Iterable infor comprehensions.

Attributes

Source: Option.scala

finaldefzip[A1 >:A,B](that:Option[B]):Option[(A1,B)]

Returns ascala.Some formed from this option and another option by combining the corresponding elements in a pair.

Returns ascala.Some formed from this option and another option by combining the corresponding elements in a pair. If either of the two options is empty,None is returned.

This is equivalent to:

(option1, option2) match {  case (Some(x), Some(y)) => Some((x, y))  case _                  => None}

Value parameters

that: the options which is going to be zipped

Attributes

Example

// Returns Some(("foo", "bar")) because both options are nonempty.Some("foo") zip Some("bar")// Returns None because `that` option is empty.Some("foo") zip None// Returns None because `this` option is empty.None zip Some("bar")

Source

Option.scala

Deprecated methods

defseq:this.type

Implicitly added byoption2Iterable

Attributes

Deprecated: [Since version 2.13.0]Iterable.seq always returns the iterable itself
Source: Iterable.scala

finaldeftoIterable:this.type

Implicitly added byoption2Iterable

Attributes

Returns: This collection as anIterable[A]. No new collection will be built ifthis is already anIterable[A].
Deprecated: [Since version 2.13.7]toIterable is internal and will be made protected; its name is similar to `toList` or `toSeq`, but it doesn\'t copy non-immutable collections
Source: Iterable.scala

Inherited methods

finaldef++[B >:A](suffix:IterableOnce[B]):Iterable[B]

Implicitly added byoption2Iterable

Alias forconcat

Attributes

Inherited from:: IterableOps
Source: Iterable.scala

finaldefaddString(b:StringBuilder): b.type

Implicitly added byoption2Iterable

Appends all elements of this collection to a string builder.

Appends all elements of this collection to a string builder. The written text consists of the string representations (w.r.t. the methodtoString) of all elements of this collection without any separator string.

Example:

scala> val a = List(1,2,3,4)a: List[Int] = List(1, 2, 3, 4)scala> val b = new StringBuilder()b: StringBuilder =scala> val h = a.addString(b)h: StringBuilder = 1234

Value parameters

b: the string builder to which elements are appended.

Attributes

Returns: the string builderb to which elements were appended.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

finaldefaddString(b:StringBuilder,sep:String): b.type

Implicitly added byoption2Iterable

Appends all elements of this collection to a string builder using a separator string.

Appends all elements of this collection to a string builder using a separator string. The written text consists of the string representations (w.r.t. the methodtoString) of all elements of this collection, 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

Value parameters

b: the string builder to which elements are appended.
sep: the separator string.

Attributes

Returns: the string builderb to which elements were appended.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defaddString(b:StringBuilder,start:String,sep:String,end:String): b.type

Implicitly added byoption2Iterable

Appends all elements of this collection to a string builder using start, end, and separator strings.

Appends all elements of this collection to a string builder using start, end, and separator strings. The written text begins with the stringstart and ends with the stringend. Inside, the string representations (w.r.t. the methodtoString) of all elements of this collection are separated by the stringsep.

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)

Value parameters

b: the string builder to which elements are appended.
end: the ending string.
sep: the separator string.
start: the starting string.

Attributes

Returns: the string builderb to which elements were appended.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defcollect[B](pf:PartialFunction[A,B]):Iterable[B]

Implicitly added byoption2Iterable

Builds a new iterable collection by applying a partial function to all elements of this iterable collection on which the function is defined.

Type parameters

B: the element type of the returned iterable collection.

Value parameters

pf: the partial function which filters and maps the iterable collection.

Attributes

Returns: a new iterable collection resulting from applying the given partial functionpf to each element on which it is defined and collecting the results. The order of the elements is preserved.
Inherited from:: IterableOps
Source: Iterable.scala

defcollectFirst[B](pf:PartialFunction[A,B]):Option[B]

Implicitly added byoption2Iterable

Finds the first element of the collection for which the given partial function is defined, and applies the partial function to it.

Note: may not terminate for infinite-sized collections.

Note: might return different results for different runs, unless the underlying collection type is ordered.

Value parameters

pf: the partial function

Attributes

Returns: an option value containing pf applied to the first value for which it is defined, orNone if none exists.
Example: Seq("a", 1, 5L).collectFirst({ case x: Int => x*10 }) = Some(10)
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defconcat[B >:A](suffix:IterableOnce[B]):Iterable[B]

Implicitly added byoption2Iterable

Returns a new iterable collection containing the elements from the left hand operand followed by the elements from the right hand operand.

Returns a new iterable collection containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the iterable collection is the most specific superclass encompassing the element types of the two operands.

Type parameters

B: the element type of the returned collection.

Value parameters

suffix: the iterable to append.

Attributes

Returns: a new iterable collection which contains all elements of this iterable collection followed by all elements ofsuffix.
Inherited from:: IterableOps
Source: Iterable.scala

defcopyToArray[B >:A](xs:Array[B],start:Int,len:Int):Int

Implicitly added byoption2Iterable

Copy elements to an array, returning the number of elements written.

Fills the given arrayxs starting at indexstart with at mostlen elements of this collection.

Copying will stop once either all the elements of this collection have been copied, or the end of the array is reached, orlen elements have been copied.

Type parameters

B: the type of the elements of the array.

Value parameters

len: the maximal number of elements to copy.
start: the starting index of xs.
xs: the array to fill.

Attributes

Returns: the number of elements written to the array
Note: Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defcopyToArray[B >:A](xs:Array[B],start:Int):Int

Implicitly added byoption2Iterable

Copies elements to an array, returning the number of elements written.

Fills the given arrayxs starting at indexstart with values of this collection.

Copying will stop once either all the elements of this collection have been copied, or the end of the array is reached.

Type parameters

B: the type of the elements of the array.

Value parameters

start: the starting index of xs.
xs: the array to fill.

Attributes

Returns: the number of elements written to the array
Note: Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defcopyToArray[B >:A](xs:Array[B]):Int

Implicitly added byoption2Iterable

Copies elements to an array, returning the number of elements written.

Fills the given arrayxs starting at indexstart with values of this collection.

Copying will stop once either all the elements of this collection have been copied, or the end of the array is reached.

Type parameters

B: the type of the elements of the array.

Value parameters

xs: the array to fill.

Attributes

Returns: the number of elements written to the array
Note: Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defcorresponds[B](that:IterableOnce[B])(p: (A,B)=>Boolean):Boolean

Implicitly added byoption2Iterable

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.

Type parameters

B: the type of the elements ofthat

Value parameters

p: the test predicate, which relates elements from both collections
that: the other collection

Attributes

Returns: true if both collections have the same length andp(x, y) istrue for all corresponding elementsx of this iterator andy ofthat, otherwisefalse
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defcount(p:A=>Boolean):Int

Implicitly added byoption2Iterable

Counts the number of elements in the collection which satisfy a predicate.

Note: will not terminate for infinite-sized collections.

Value parameters

p: the predicate used to test elements.

Attributes

Returns: the number of elements satisfying the predicatep.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defdrop(n:Int):Iterable[A]

Implicitly added byoption2Iterable

Selects all elements except the firstn ones.

Note: might return different results for different runs, unless the underlying collection type is ordered.

Value parameters

n: the number of elements to drop from this iterable collection.

Attributes

Returns: a iterable collection consisting of all elements of this iterable collection except the firstn ones, or else the empty iterable collection, if this iterable collection has less thann elements. Ifn is negative, don't drop any elements.
Inherited from:: IterableOps
Source: Iterable.scala

defdropRight(n:Int):Iterable[A]

Implicitly added byoption2Iterable

Selects all elements except lastn ones.

Note: might return different results for different runs, unless the underlying collection type is ordered.

Value parameters

n: the number of elements to drop from this iterable collection.

Attributes

Returns: a iterable collection consisting of all elements of this iterable collection except the lastn ones, or else the empty iterable collection, if this iterable collection has less thann elements. Ifn is negative, don't drop any elements.
Inherited from:: IterableOps
Source: Iterable.scala

defdropWhile(p:A=>Boolean):Iterable[A]

Implicitly added byoption2Iterable

Selects all elements except the longest prefix that satisfies a predicate.

The matching prefix starts with the first element of this iterable collection, and the element following the prefix is the first element that does not satisfy the predicate. The matching prefix may be empty, so that this method returns the entire iterable collection.

Example:

scala> List(1, 2, 3, 100, 4).dropWhile(n => n < 10)val res0: List[Int] = List(100, 4)scala> List(1, 2, 3, 100, 4).dropWhile(n => n == 0)val res1: List[Int] = List(1, 2, 3, 100, 4)

Usespan to obtain both the prefix and suffix. UsefilterNot to drop all elements that satisfy the predicate.

Note: might return different results for different runs, unless the underlying collection type is ordered.

Value parameters

p: The predicate used to test elements.

Attributes

Returns: the longest suffix of this iterable collection whose first element does not satisfy the predicatep.
Inherited from:: IterableOps
Source: Iterable.scala

defexists(p:A=>Boolean):Boolean

Implicitly added byoption2Iterable

Tests whether a predicate holds for at least one element of this collection.

Note: may not terminate for infinite-sized collections.

Value parameters

p: the predicate used to test elements.

Attributes

Returns: true if the given predicatep is satisfied by at least one element of this collection, otherwisefalse
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

deffilter(pred:A=>Boolean):Iterable[A]

Implicitly added byoption2Iterable

Selects all elements of this iterable collection which satisfy a predicate.

Value parameters

p: the predicate used to test elements.

Attributes

Returns: a new iterable collection consisting of all elements of this iterable collection that satisfy the given predicatep. The order of the elements is preserved.
Inherited from:: IterableOps
Source: Iterable.scala

deffilterNot(pred:A=>Boolean):Iterable[A]

Implicitly added byoption2Iterable

Selects all elements of this iterable collection which do not satisfy a predicate.

Value parameters

pred: the predicate used to test elements.

Attributes

Returns: a new iterable collection consisting of all elements of this iterable collection that do not satisfy the given predicatepred. Their order may not be preserved.
Inherited from:: IterableOps
Source: Iterable.scala

deffind(p:A=>Boolean):Option[A]

Implicitly added byoption2Iterable

Finds the first element of the collection satisfying a predicate, if any.

Note: may not terminate for infinite-sized collections.

Note: might return different results for different runs, unless the underlying collection type is ordered.

Value parameters

p: the predicate used to test elements.

Attributes

Returns: an option value containing the first element in the collection that satisfiesp, orNone if none exists.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defflatMap[B](f:A=>IterableOnce[B]):Iterable[B]

Implicitly added byoption2Iterable

Builds a new iterable collection by applying a function to all elements of this iterable collection and using the elements of the resulting collections.

For example:

def getWords(lines: Seq[String]): Seq[String] = lines flatMap (line => line split "\\W+")

The type of the resulting collection is guided by the static type of iterable collection. This might cause unexpected results sometimes. For example:

// lettersOf will return a Seq[Char] of likely repeated letters, instead of a Setdef lettersOf(words: Seq[String]) = words flatMap (word => word.toSet)// lettersOf will return a Set[Char], not a Seqdef 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)

Type parameters

B: the element type of the returned collection.

Value parameters

f: the function to apply to each element.

Attributes

Returns: a new iterable collection resulting from applying the given collection-valued functionf to each element of this iterable collection and concatenating the results.
Inherited from:: IterableOps
Source: Iterable.scala

defflatten[B](implicitasIterable:A=>IterableOnce[B]):Iterable[B]

Implicitly added byoption2Iterable

Converts this iterable collection of iterable collections into a iterable collection formed by the elements of these iterable collections.

The resulting collection's type will be guided by the type of iterable collection. For example:

val xs = List(           Set(1, 2, 3),           Set(1, 2, 3)         ).flatten// xs == List(1, 2, 3, 1, 2, 3)val ys = Set(           List(1, 2, 3),           List(3, 2, 1)         ).flatten// ys == Set(1, 2, 3)

Type parameters

B: the type of the elements of each iterable collection.

Value parameters

asIterable: an implicit conversion which asserts that the element type of this iterable collection is anIterable.

Attributes

Returns: a new iterable collection resulting from concatenating all element iterable collections.
Inherited from:: IterableOps
Source: Iterable.scala

deffold[A1 >:A](z:A1)(op: (A1,A1)=>A1):A1

Implicitly added byoption2Iterable

Applies the given binary operatorop to the given initial valuez and all elements of this collection.

For each application of the operator, each operand is either an element of this collection, the initial value, or another such application of the operator.

The order of applications of the operator is unspecified and may be nondeterministic. Each element appears exactly once in the computation. The initial value may be used an arbitrary number of times, but at least once.

If this collection is ordered, then for any application of the operator, the element(s) appearing in the left operand will precede those in the right.

Note: might return different results for different runs, unless either of the following conditions is met: (1) the operator is associative, and the underlying collection type is ordered; or (2) the operator is associative and commutative. In either case, it is also necessary that the initial value be a neutral value for the operator, e.g.Nil forList concatenation or1 for multiplication.

The default implementation inIterableOnce is equivalent tofoldLeft but may be overridden for more efficient traversal orders.

Note: will not terminate for infinite-sized collections.

Type parameters

A1: The type parameter for the binary operator, a supertype ofA.

Value parameters

op: A binary operator; must be associative for the result to always be the same across runs.
z: An initial value; may be used an arbitrary number of times in the computation of the result; must be a neutral value forop for the result to always be the same across runs.

Attributes

Returns: The result of applyingop between all the elements andz, orz if this collection is empty.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

deffoldLeft[B](z:B)(op: (B,A)=>B):B

Implicitly added byoption2Iterable

Applies the given binary operatorop to the given initial valuez and all elements of this collection, going left to right.

Applies the given binary operatorop to the given initial valuez and all elements of this collection, going left to right. Returns the initial value if this collection is empty.

"Going left to right" only makes sense if this collection is ordered: then ifx1,x2, ...,xn are the elements of this collection, the result isop( op( ... op( op(z, x1), x2) ... ), xn).

If this collection is not ordered, then for each application of the operator, each right operand is an element. In addition, the leftmost operand is the initial value, and each other left operand is itself an application of the operator. The elements of this collection and the initial value all appear exactly once in the computation.

Note: might return different results for different runs, unless the underlying collection type is ordered.

Note: will not terminate for infinite-sized collections.

Type parameters

B: The result type of the binary operator.

Value parameters

op: A binary operator.
z: An initial value.

Attributes

Returns: The result of applyingop toz and all elements of this collection, going left to right. Returnsz if this collection is empty.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

deffoldRight[B](z:B)(op: (A,B)=>B):B

Implicitly added byoption2Iterable

Applies the given binary operatorop to all elements of this collection and the given initial valuez, going right to left.

Applies the given binary operatorop to all elements of this collection and the given initial valuez, going right to left. Returns the initial value if this collection is empty.

"Going right to left" only makes sense if this collection is ordered: then ifx1,x2, ...,xn are the elements of this collection, the result isop(x1, op(x2, op( ... op(xn, z) ... ))).

If this collection is not ordered, then for each application of the operator, each left operand is an element. In addition, the rightmost operand is the initial value, and each other right operand is itself an application of the operator. The elements of this collection and the initial value all appear exactly once in the computation.

Note: might return different results for different runs, unless the underlying collection type is ordered.

Note: will not terminate for infinite-sized collections.

Type parameters

B: The result type of the binary operator.

Value parameters

op: A binary operator.
z: An initial value.

Attributes

Returns: The result of applyingop to all elements of this collection andz, going right to left. Returnsz if this collection is empty.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defforall(p:A=>Boolean):Boolean

Implicitly added byoption2Iterable

Tests whether a predicate holds for all elements of this collection.

Note: may not terminate for infinite-sized collections.

Value parameters

p: the predicate used to test elements.

Attributes

Returns: true if this collection is empty or the given predicatep holds for all elements of this collection, otherwisefalse.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defforeach[U](f:A=>U):Unit

Implicitly added byoption2Iterable

Appliesf to each element for its side effects.

Appliesf to each element for its side effects. Note:U parameter needed to help scalac's type inference.

Attributes

Inherited from:: IterableOnceOps
Source: IterableOnce.scala

protecteddeffromSpecific(coll:IterableOnce[A]):Iterable[A]

Implicitly added byoption2Iterable

Defines how to turn a givenIterable[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

Note: When implementing a custom collection type and refiningC to the new type, this method needs to be overridden (the compiler will issue an error otherwise). In the common case whereC =:= CC[A], this can be done by mixing in thescala.collection.IterableFactoryDefaults trait, which implements the method usingiterableFactory.
As witnessed by the@uncheckedVariance annotation, using this method might be unsound. However, as long as it is called with anIterable[A] obtained fromthis collection (as it is the case in the implementations of operations where we use aView[A]), it is safe.
Inherited from:: IterableFactoryDefaults
Source: Iterable.scala

defgroupBy[K](f:A=>K):Map[K,Iterable[A]]

Implicitly added byoption2Iterable

Partitions this iterable collection into a map of iterable collections according to some discriminator function.

Note: Even when applied to a view or a lazy collection it will always force the elements.

Type parameters

K: the type of keys returned by the discriminator function.

Value parameters

f: the discriminator function.

Attributes

Returns

A map from keys to iterable collections such that the following invariant holds:

(xs groupBy f)(k) = xs filter (x => f(x) == k)

That is, every keyk is bound to a iterable collection of those elementsx for whichf(x) equalsk.

Inherited from:

IterableOps

Source

Iterable.scala

defgroupMap[K,B](key:A=>K)(f:A=>B):Map[K,Iterable[B]]

Implicitly added byoption2Iterable

Partitions this iterable collection into a map of iterable collections according to a discriminator functionkey.

Partitions this iterable collection into a map of iterable collections according to a discriminator functionkey. Each element in a group is transformed into a value of typeB using thevalue function.

It is equivalent togroupBy(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.

Type parameters

B: the type of values returned by the transformation function
K: the type of keys returned by the discriminator function

Value parameters

f: the element transformation function
key: the discriminator function

Attributes

Inherited from:: IterableOps
Source: Iterable.scala

defgroupMapReduce[K,B](key:A=>K)(f:A=>B)(reduce: (B,B)=>B):Map[K,B]

Implicitly added byoption2Iterable

Partitions this iterable collection into a map according to a discriminator functionkey.

Partitions this iterable collection into a map according to a discriminator functionkey. All the values that have the same discriminator are then transformed by thef function and then reduced into a single value with thereduce function.

It is equivalent togroupBy(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.

Attributes

Inherited from:: IterableOps
Source: Iterable.scala

defgrouped(size:Int):Iterator[Iterable[A]]

Implicitly added byoption2Iterable

Partitions elements in fixed size iterable collections.

Value parameters

size: the number of elements per group

Attributes

Returns: An iterator producing iterable collections of sizesize, except the last will be less than sizesize if the elements don't divide evenly.
See also: scala.collection.Iterator, methodgrouped
Inherited from:: IterableOps
Source: Iterable.scala

defhead:A

Implicitly added byoption2Iterable

Selects the first element of this iterable collection.

Note: might return different results for different runs, unless the underlying collection type is ordered.

Attributes

Returns: the first element of this iterable collection.
Throws: NoSuchElementExceptionif the iterable collection is empty.
Inherited from:: IterableOps
Source: Iterable.scala

defheadOption:Option[A]

Implicitly added byoption2Iterable

Optionally selects the first element.

Note: might return different results for different runs, unless the underlying collection type is ordered.

Attributes

Returns: the first element of this iterable collection if it is nonempty,None if it is empty.
Inherited from:: IterableOps
Source: Iterable.scala

definit:Iterable[A]

Implicitly added byoption2Iterable

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.

Attributes

Inherited from:: IterableOps
Source: Iterable.scala

definits:Iterator[Iterable[A]]

Implicitly added byoption2Iterable

Iterates over the inits of this iterable collection.

Iterates over the inits of this iterable collection. The first value will be this iterable collection and the final one will be an empty iterable collection, with the intervening values the results of successive applications ofinit.

Note: Even when applied to a view or a lazy collection it will always force the elements.

Attributes

Returns: an iterator over all the inits of this iterable collection
Example: List(1,2,3).inits = Iterator(List(1,2,3), List(1,2), List(1), Nil)
Inherited from:: IterableOps
Source: Iterable.scala

defisEmpty:Boolean

Implicitly added byoption2Iterable

Tests whether the collection is empty.

Note: The default implementation creates and discards an iterator.

Note: Implementations in subclasses that are not repeatedly iterable must take care not to consume any elements whenisEmpty is called.

Attributes

Returns: true if the collection contains no elements,false otherwise.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defknownSize:Int

Implicitly added byoption2Iterable

The number of elements in this collection, if it can be cheaply computed, -1 otherwise.

The number of elements in this collection, if it can be cheaply computed, -1 otherwise. Cheaply usually means: Not requiring a collection traversal.

Attributes

Inherited from:: IterableOnce
Source: IterableOnce.scala

deflast:A

Implicitly added byoption2Iterable

Selects the last element.

Note: might return different results for different runs, unless the underlying collection type is ordered.

Attributes

Returns: The last element of this iterable collection.
Throws: NoSuchElementExceptionIf the iterable collection is empty.
Inherited from:: IterableOps
Source: Iterable.scala

deflastOption:Option[A]

Implicitly added byoption2Iterable

Optionally selects the last element.

Note: might return different results for different runs, unless the underlying collection type is ordered.

Attributes

Returns: the last element of this iterable collection$ if it is nonempty,None if it is empty.
Inherited from:: IterableOps
Source: Iterable.scala

defmap[B](f:A=>B):Iterable[B]

Implicitly added byoption2Iterable

Builds a new iterable collection by applying a function to all elements of this iterable collection.

Type parameters

B: the element type of the returned iterable collection.

Value parameters

f: the function to apply to each element.

Attributes

Returns: a new iterable collection resulting from applying the given functionf to each element of this iterable collection and collecting the results.
Inherited from:: IterableOps
Source: Iterable.scala

defmax[B >:A](implicitord:Ordering[B]):A

Implicitly added byoption2Iterable

Finds the largest element.

Note: will not terminate for infinite-sized collections.

Type parameters

B: The type over which the ordering is defined.

Value parameters

ord: An ordering to be used for comparing elements.

Attributes

Returns: the largest element of this collection with respect to the orderingord.
Throws: UnsupportedOperationExceptionif this collection is empty.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defmaxBy[B](f:A=>B)(implicitord:Ordering[B]):A

Implicitly added byoption2Iterable

Finds the first element which yields the largest value measured by functionf.

Note: will not terminate for infinite-sized collections.

Type parameters

B: The result type of the functionf.

Value parameters

cmp: An ordering to be used for comparing elements.
f: The measuring function.

Attributes

Returns: the first element of this collection with the largest value measured by functionf with respect to the orderingcmp.
Throws: UnsupportedOperationExceptionif this collection is empty.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defmaxByOption[B](f:A=>B)(implicitord:Ordering[B]):Option[A]

Implicitly added byoption2Iterable

Finds the first element which yields the largest value measured by functionf.

Note: will not terminate for infinite-sized collections.

Type parameters

B: The result type of the functionf.

Value parameters

cmp: An ordering to be used for comparing elements.
f: The measuring function.

Attributes

Returns: an option value containing the first element of this collection with the largest value measured by functionf with respect to the orderingcmp.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defmaxOption[B >:A](implicitord:Ordering[B]):Option[A]

Implicitly added byoption2Iterable

Finds the largest element.

Note: will not terminate for infinite-sized collections.

Type parameters

B: The type over which the ordering is defined.

Value parameters

ord: An ordering to be used for comparing elements.

Attributes

Returns: an option value containing the largest element of this collection with respect to the orderingord.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defmin[B >:A](implicitord:Ordering[B]):A

Implicitly added byoption2Iterable

Finds the smallest element.

Note: will not terminate for infinite-sized collections.

Type parameters

B: The type over which the ordering is defined.

Value parameters

ord: An ordering to be used for comparing elements.

Attributes

Returns: the smallest element of this collection with respect to the orderingord.
Throws: UnsupportedOperationExceptionif this collection is empty.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defminBy[B](f:A=>B)(implicitord:Ordering[B]):A

Implicitly added byoption2Iterable

Finds the first element which yields the smallest value measured by functionf.

Note: will not terminate for infinite-sized collections.

Type parameters

B: The result type of the functionf.

Value parameters

cmp: An ordering to be used for comparing elements.
f: The measuring function.

Attributes

Returns: the first element of this collection with the smallest value measured by functionf with respect to the orderingcmp.
Throws: UnsupportedOperationExceptionif this collection is empty.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defminByOption[B](f:A=>B)(implicitord:Ordering[B]):Option[A]

Implicitly added byoption2Iterable

Finds the first element which yields the smallest value measured by functionf.

Note: will not terminate for infinite-sized collections.

Type parameters

B: The result type of the functionf.

Value parameters

cmp: An ordering to be used for comparing elements.
f: The measuring function.

Attributes

Returns: an option value containing the first element of this collection with the smallest value measured by functionf with respect to the orderingcmp.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defminOption[B >:A](implicitord:Ordering[B]):Option[A]

Implicitly added byoption2Iterable

Finds the smallest element.

Note: will not terminate for infinite-sized collections.

Type parameters

B: The type over which the ordering is defined.

Value parameters

ord: An ordering to be used for comparing elements.

Attributes

Returns: an option value containing the smallest element of this collection with respect to the orderingord.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

finaldefmkString:String

Implicitly added byoption2Iterable

Displays all elements of this collection in a string.

Delegates to addString, which can be overridden.

Attributes

Returns: a string representation of this collection. In the resulting string the string representations (w.r.t. the methodtoString) of all elements of this collection follow each other without any separator string.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

finaldefmkString(sep:String):String

Implicitly added byoption2Iterable

Displays all elements of this collection in a string using a separator string.

Delegates to addString, which can be overridden.

Value parameters

sep: the separator string.

Attributes

Returns: a string representation of this collection. In the resulting string the string representations (w.r.t. the methodtoString) of all elements of this collection are separated by the stringsep.
Example: List(1, 2, 3).mkString("|") = "1|2|3"
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

finaldefmkString(start:String,sep:String,end:String):String

Implicitly added byoption2Iterable

Displays all elements of this collection in a string using start, end, and separator strings.

Delegates to addString, which can be overridden.

Value parameters

end: the ending string.
sep: the separator string.
start: the starting string.

Attributes

Returns: a string representation of this collection. The resulting string begins with the stringstart and ends with the stringend. Inside, the string representations (w.r.t. the methodtoString) of all elements of this collection are separated by the stringsep.
Example: List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

protecteddefnewSpecificBuilder:Builder[A,Iterable[A]]

Implicitly added byoption2Iterable

Attributes

Returns: a strict builder for the same collection type. Note that in the case of lazy collections (e.g.scala.collection.View orscala.collection.immutable.LazyList), it is possible to implement this method but the resultingBuilder will break laziness. As a consequence, operations should preferably be implemented withfromSpecific instead of this method.
Note: When implementing a custom collection type and refiningC to the new type, this method needs to be overridden (the compiler will issue an error otherwise). In the common case whereC =:= CC[A], this can be done by mixing in thescala.collection.IterableFactoryDefaults trait, which implements the method usingiterableFactory.
As witnessed by the@uncheckedVariance annotation, using this method might be unsound. However, as long as the returned builder is only fed withA values taken fromthis instance, it is safe.
Inherited from:: IterableFactoryDefaults
Source: Iterable.scala

defnonEmpty:Boolean

Implicitly added byoption2Iterable

Tests whether the collection is not empty.

Attributes

Returns: true if the collection contains at least one element,false otherwise.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defpartition(p:A=>Boolean): (Iterable[A],Iterable[A])

Implicitly added byoption2Iterable

A pair of, first, all elements that satisfy predicatep and, second, all elements that do not.

A pair of, first, all elements that satisfy predicatep and, second, all elements that do not. Interesting because it splits a collection in two.

The default implementation provided here needs to traverse the collection twice. Strict collections have an overridden version ofpartition inStrictOptimizedIterableOps, which requires only a single traversal.

Attributes

Inherited from:: IterableOps
Source: Iterable.scala

defpartitionMap[A1,A2](f:A=>Either[A1,A2]): (Iterable[A1],Iterable[A2])

Implicitly added byoption2Iterable

Applies a functionf to each element of the iterable collection and returns a pair of iterable collections: the first one made of those values returned byf that were wrapped inscala.util.Left, and the second one made of those wrapped inscala.util.Right.

Example:

val xs = Iterable(1, "one", 2, "two", 3, "three") partitionMap { case i: Int => Left(i) case s: String => Right(s)}// xs == (Iterable(1, 2, 3),//        Iterable(one, two, three))

Type parameters

A1: the element type of the first resulting collection
A2: the element type of the second resulting collection

Value parameters

f: the 'split function' mapping the elements of this iterable collection to anscala.util.Either

Attributes

Returns: a pair of iterable collections: the first one made of those values returned byf that were wrapped inscala.util.Left, and the second one made of those wrapped inscala.util.Right.
Inherited from:: IterableOps
Source: Iterable.scala

defproduct[B >:A](implicitnum:Numeric[B]):B

Implicitly added byoption2Iterable

Multiplies together the elements of this collection.

The default implementation usesreduce for a known non-empty collection,foldLeft otherwise.

Note: will not terminate for infinite-sized collections.

Type parameters

B: the result type of the* operator.

Value parameters

num: an implicit parameter defining a set of numeric operations which includes the* operator to be used in forming the product.

Attributes

Returns: the product of all elements of this collection with respect to the* operator innum.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defproductElementName(n:Int):String

The name of the nth element of this product, 0-based.

The name of the nth element of this product, 0-based. In the default implementation, an empty string.

Value parameters

n: the index of the element name to return

Attributes

Returns: the name of the specified element
Throws: IndexOutOfBoundsExceptionif then is out of range(n < 0 || n >= productArity).
Inherited from:: Product
Source: Product.scala

defproductElementNames:Iterator[String]

An iterator over the names of all the elements of this product.

Attributes

Inherited from:: Product
Source: Product.scala

defproductIterator:Iterator[Any]

An iterator over all the elements of this product.

Attributes

Returns: in the default implementation, anIterator[Any]
Inherited from:: Product
Source: Product.scala

defproductPrefix:String

A string used in thetoString methods of derived classes.

A string used in thetoString methods of derived classes. Implementations may override this method to prepend a string prefix to the result oftoString methods.

Attributes

Returns: in the default implementation, the empty string
Inherited from:: Product
Source: Product.scala

defreduce[B >:A](op: (B,B)=>B):B

Implicitly added byoption2Iterable

Applies the given binary operatorop to all elements of this collection.

For each application of the operator, each operand is either an element of this collection or another such application of the operator. The order of applications of the operator is unspecified and may be nondeterministic. Each element appears exactly once in the computation.

If this collection is ordered, then for any application of the operator, the element(s) appearing in the left operand will precede those in the right.

Note: will not terminate for infinite-sized collections.

Type parameters

B: The type parameter for the binary operator, a supertype ofA.

Value parameters

op: A binary operator; must be associative for the result to always be the same across runs.

Attributes

Returns: The result of applyingop between all the elements if the collection is nonempty.
Throws: UnsupportedOperationExceptionif this collection is empty.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defreduceLeft[B >:A](op: (B,A)=>B):B

Implicitly added byoption2Iterable

Applies the given binary operatorop to all elements of this collection, going left to right.

"Going left to right" only makes sense if this collection is ordered: then ifx1,x2, ...,xn are the elements of this collection, the result isop( op( op( ... op(x1, x2) ... ), xn-1), xn).

If this collection is not ordered, then for each application of the operator, each right operand is an element. In addition, the leftmost operand is the first element of this collection and each other left operand is itself an application of the operator. Each element appears exactly once in the computation.

Note: might return different results for different runs, unless the underlying collection type is ordered or the operator is associative and commutative.

Note: will not terminate for infinite-sized collections.

Type parameters

B: The result type of the binary operator, a supertype ofA.

Value parameters

op: A binary operator.

Attributes

Returns: The result of applyingop to all elements of this collection, going left to right.
Throws: UnsupportedOperationExceptionif this collection is empty.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defreduceLeftOption[B >:A](op: (B,A)=>B):Option[B]

Implicitly added byoption2Iterable

If this collection is nonempty, reduces it with the given binary operatorop, going left to right.

The behavior is the same asreduceLeft except that the value isNone if the collection is empty. Each element appears exactly once in the computation.

Note: might return different results for different runs, unless the underlying collection type is ordered or the operator is associative and commutative.

Note: will not terminate for infinite-sized collections.

Type parameters

B: The result type of the binary operator, a supertype ofA.

Value parameters

op: A binary operator.

Attributes

Returns: The result of reducing this collection withop going left to right if the collection is nonempty, inside aSome, andNone otherwise.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defreduceOption[B >:A](op: (B,B)=>B):Option[B]

Implicitly added byoption2Iterable

If this collection is nonempty, reduces it with the given binary operatorop.

The behavior is the same asreduce except that the value isNone if the collection is empty. The order of applications of the operator is unspecified and may be nondeterministic. Each element appears exactly once in the computation.

Note: will not terminate for infinite-sized collections.

Type parameters

B: A type parameter for the binary operator, a supertype ofA.

Value parameters

op: A binary operator; must be associative for the result to always be the same across runs.

Attributes

Returns: The result of reducing this collection withop if the collection is nonempty, inside aSome, andNone otherwise.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defreduceRight[B >:A](op: (A,B)=>B):B

Implicitly added byoption2Iterable

Applies the given binary operatorop to all elements of this collection, going right to left.

"Going right to left" only makes sense if this collection is ordered: then ifx1,x2, ...,xn are the elements of this collection, the result isop(x1, op(x2, op( ... op(xn-1, xn) ... ))).

If this collection is not ordered, then for each application of the operator, each left operand is an element. In addition, the rightmost operand is the last element of this collection and each other right operand is itself an application of the operator. Each element appears exactly once in the computation.

Note: might return different results for different runs, unless the underlying collection type is ordered or the operator is associative and commutative.

Note: will not terminate for infinite-sized collections.

Type parameters

B: The result type of the binary operator, a supertype ofA.

Value parameters

op: A binary operator.

Attributes

Returns: The result of applyingop to all elements of this collection, going right to left.
Throws: UnsupportedOperationExceptionif this collection is empty.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defreduceRightOption[B >:A](op: (A,B)=>B):Option[B]

Implicitly added byoption2Iterable

If this collection is nonempty, reduces it with the given binary operatorop, going right to left.

The behavior is the same asreduceRight except that the value isNone if the collection is empty. Each element appears exactly once in the computation.

Note: might return different results for different runs, unless the underlying collection type is ordered or the operator is associative and commutative.

Note: will not terminate for infinite-sized collections.

Type parameters

B: The result type of the binary operator, a supertype ofA.

Value parameters

op: A binary operator.

Attributes

Returns: The result of reducing this collection withop going right to left if the collection is nonempty, inside aSome, andNone otherwise.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

protecteddefreversed:Iterable[A]

Implicitly added byoption2Iterable

Attributes

Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defscan[B >:A](z:B)(op: (B,B)=>B):Iterable[B]

Implicitly added byoption2Iterable

Computes a prefix scan of the elements of the collection.

Note: The neutral elementz may be applied more than once.

Type parameters

B: element type of the resulting collection

Value parameters

op: the associative operator for the scan
z: neutral element for the operatorop

Attributes

Returns: a new iterable collection containing the prefix scan of the elements in this iterable collection
Inherited from:: IterableOps
Source: Iterable.scala

defscanLeft[B](z:B)(op: (B,A)=>B):Iterable[B]

Implicitly added byoption2Iterable

Produces a iterable collection containing cumulative results of applying the operator going left to right, including the initial value.

Note: will not terminate for infinite-sized collections.

Note: might return different results for different runs, unless the underlying collection type is ordered.

Type parameters

B: the type of the elements in the resulting collection

Value parameters

op: the binary operator applied to the intermediate result and the element
z: the initial value

Attributes

Returns: collection with intermediate results
Inherited from:: IterableOps
Source: Iterable.scala

defscanRight[B](z:B)(op: (A,B)=>B):Iterable[B]

Implicitly added byoption2Iterable

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)

Type parameters

B: the type of the elements in the resulting collection

Value parameters

op: the binary operator applied to the intermediate result and the element
z: the initial value

Attributes

Returns: collection with intermediate results
Inherited from:: IterableOps
Source: Iterable.scala

defsize:Int

Implicitly added byoption2Iterable

The size of this collection.

Note: will not terminate for infinite-sized collections.

Attributes

Returns: the number of elements in this collection.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defsizeCompare(that:Iterable[_]):Int

Implicitly added byoption2Iterable

Compares the size of this iterable collection to the size of anotherIterable.

Value parameters

that: theIterable whose size is compared with this iterable collection's size.

Attributes

Returns

A valuex where

x <  0       if this.size <  that.sizex == 0       if this.size == that.sizex >  0       if this.size >  that.size

The method as implemented here does not callsize directly; its running time isO(this.size min that.size) instead ofO(this.size + that.size). The method should be overridden if computingsize is cheap andknownSize returns-1.

Inherited from:

IterableOps

Source

Iterable.scala

defsizeCompare(otherSize:Int):Int

Implicitly added byoption2Iterable

Compares the size of this iterable collection to a test value.

Value parameters

otherSize: the test value that gets compared with the size.

Attributes

Returns

A valuex where

x <  0       if this.size <  otherSizex == 0       if this.size == otherSizex >  0       if this.size >  otherSize

The method as implemented here does not callsize directly; its running time isO(size min otherSize) instead ofO(size). The method should be overridden if computingsize is cheap andknownSize returns-1.

See also

sizeIs

Inherited from:

IterableOps

Source

Iterable.scala

finaldefsizeIs:SizeCompareOps

Implicitly added byoption2Iterable

Returns a value class containing operations for comparing the size of this iterable collection to a test value.

These operations are implemented in terms ofsizeCompare(Int), and allow the following more readable usages:

this.sizeIs < size     // this.sizeCompare(size) < 0this.sizeIs <= size    // this.sizeCompare(size) <= 0this.sizeIs == size    // this.sizeCompare(size) == 0this.sizeIs != size    // this.sizeCompare(size) != 0this.sizeIs >= size    // this.sizeCompare(size) >= 0this.sizeIs > size     // this.sizeCompare(size) > 0

Attributes

Inherited from:: IterableOps
Source: Iterable.scala

defslice(from:Int,until:Int):Iterable[A]

Implicitly added byoption2Iterable

Selects an interval of elements.

Selects an interval of elements. The returned iterable collection is made up of all elementsx which satisfy the invariant:

from <= indexOf(x) < until

Note: might return different results for different runs, unless the underlying collection type is ordered.

Value parameters

from: the lowest index to include from this iterable collection.
until: the lowest index to EXCLUDE from this iterable collection.

Attributes

Returns: a iterable collection containing the elements greater than or equal to indexfrom extending up to (but not including) indexuntil of this iterable collection.
Inherited from:: IterableOps
Source: Iterable.scala

defsliding(size:Int,step:Int):Iterator[Iterable[A]]

Implicitly added byoption2Iterable

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.

Value parameters

size: the number of elements per group
step: the distance between the first elements of successive groups

Attributes

Returns: An iterator producing iterable collections of sizesize, except the last element (which may be the only element) will be smaller if there are fewer thansize elements remaining to be grouped.
See also: scala.collection.Iterator, methodsliding
Example: 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))
Inherited from:: IterableOps
Source: Iterable.scala

defsliding(size:Int):Iterator[Iterable[A]]

Implicitly added byoption2Iterable

Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done ingrouped.)

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.

Value parameters

size: the number of elements per group

Attributes

Returns: An iterator producing iterable collections of sizesize, except for a non-empty collection with less thansize elements, which returns an iterator that produces the source collection itself as its only element.
See also: scala.collection.Iterator, methodsliding
Example: 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))
Inherited from:: IterableOps
Source: Iterable.scala

defspan(p:A=>Boolean): (Iterable[A],Iterable[A])

Implicitly added byoption2Iterable

Splits this iterable collection into a prefix/suffix pair according to a predicate.

Note:c span p is equivalent to (but possibly more efficient than)(c takeWhile p, c dropWhile p), provided the evaluation of the predicatep does not cause any side-effects.

Note: might return different results for different runs, unless the underlying collection type is ordered.

Value parameters

p: the test predicate

Attributes

Returns: a pair consisting of the longest prefix of this iterable collection whose elements all satisfyp, and the rest of this iterable collection.
Inherited from:: IterableOps
Source: Iterable.scala

defstepper[S <:Stepper[_]](implicitshape:StepperShape[A,S]):S

Implicitly added byoption2Iterable

Returns ascala.collection.Stepper for the elements of this collection.

The Stepper enables creating a Java stream to operate on the collection, seescala.jdk.StreamConverters. For collections holding primitive values, the Stepper can be used as an iterator which doesn't box the elements.

The implicitscala.collection.StepperShape parameter defines the resulting Stepper type according to the element type of this collection.

For collections ofInt,Short,Byte orChar, anscala.collection.IntStepper is returned
For collections ofDouble orFloat, ascala.collection.DoubleStepper is returned
For collections ofLong ascala.collection.LongStepper is returned
For any other element type, anscala.collection.AnyStepper is returned

Note that this method is overridden in subclasses and the return type is refined toS with EfficientSplit, for examplescala.collection.IndexedSeqOps.stepper. For Steppers marked withscala.collection.Stepper.EfficientSplit, the converters inscala.jdk.StreamConverters allow creating parallel streams, whereas bare Steppers can be converted only to sequential streams.

Attributes

Inherited from:: IterableOnce
Source: IterableOnce.scala

defstepper[S <:Stepper[_]](implicitshape:StepperShape[A,S]):S

Returns ascala.collection.Stepper for the elements of this collection.

The implicitscala.collection.StepperShape parameter defines the resulting Stepper type according to the element type of this collection.

For collections ofInt,Short,Byte orChar, anscala.collection.IntStepper is returned
For collections ofDouble orFloat, ascala.collection.DoubleStepper is returned
For collections ofLong ascala.collection.LongStepper is returned
For any other element type, anscala.collection.AnyStepper is returned

Attributes

Inherited from:: IterableOnce
Source: IterableOnce.scala

defsum[B >:A](implicitnum:Numeric[B]):B

Implicitly added byoption2Iterable

Sums the elements of this collection.

The default implementation usesreduce for a known non-empty collection,foldLeft otherwise.

Note: will not terminate for infinite-sized collections.

Type parameters

B: the result type of the+ operator.

Value parameters

num: an implicit parameter defining a set of numeric operations which includes the+ operator to be used in forming the sum.

Attributes

Returns: the sum of all elements of this collection with respect to the+ operator innum.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

deftail:Iterable[A]

Implicitly added byoption2Iterable

The rest of the collection without its first element.

Attributes

Inherited from:: IterableOps
Source: Iterable.scala

deftails:Iterator[Iterable[A]]

Implicitly added byoption2Iterable

Iterates over the tails of this iterable collection.

Iterates over the tails of this iterable collection. The first value will be this iterable collection and the final one will be an empty iterable collection, with the intervening values the results of successive applications oftail.

Attributes

Returns: an iterator over all the tails of this iterable collection
Example: List(1,2,3).tails = Iterator(List(1,2,3), List(2,3), List(3), Nil)
Inherited from:: IterableOps
Source: Iterable.scala

deftake(n:Int):Iterable[A]

Implicitly added byoption2Iterable

Selects the firstn elements.

Note: might return different results for different runs, unless the underlying collection type is ordered.

Value parameters

n: the number of elements to take from this iterable collection.

Attributes

Returns: a iterable collection consisting only of the firstn elements of this iterable collection, or else the whole iterable collection, if it has less thann elements. Ifn is negative, returns an empty iterable collection.
Inherited from:: IterableOps
Source: Iterable.scala

deftakeRight(n:Int):Iterable[A]

Implicitly added byoption2Iterable

Selects the lastn elements.

Note: might return different results for different runs, unless the underlying collection type is ordered.

Value parameters

n: the number of elements to take from this iterable collection.

Attributes

Returns: a iterable collection consisting only of the lastn elements of this iterable collection, or else the whole iterable collection, if it has less thann elements. Ifn is negative, returns an empty iterable collection.
Inherited from:: IterableOps
Source: Iterable.scala

deftakeWhile(p:A=>Boolean):Iterable[A]

Implicitly added byoption2Iterable

Takes longest prefix of elements that satisfy a predicate.

Note: might return different results for different runs, unless the underlying collection type is ordered.

Value parameters

p: The predicate used to test elements.

Attributes

Returns: the longest prefix of this iterable collection whose elements all satisfy the predicatep.
Inherited from:: IterableOps
Source: Iterable.scala

defto[C1](factory:Factory[A,C1]):C1

Implicitly added byoption2Iterable

Given a collection factoryfactory, converts this collection to the appropriate representation for the current element typeA.

Given a collection factoryfactory, converts 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]

Attributes

Inherited from:: IterableOnceOps
Source: IterableOnce.scala

deftoArray[B >:A :ClassTag]:Array[B]

Implicitly added byoption2Iterable

Converts this collection to anArray.

Implementation note: DO NOT callArray.from from this method.

Type parameters

B: The type of elements of the result, a supertype ofA.

Attributes

Returns: This collection as anArray[B].
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

finaldeftoBuffer[B >:A]:Buffer[B]

Implicitly added byoption2Iterable

Converts this collection to aBuffer.

Type parameters

B: The type of elements of the result, a supertype ofA.

Attributes

Returns: This collection as aBuffer[B].
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

deftoIndexedSeq:IndexedSeq[A]

Implicitly added byoption2Iterable

Converts this collection to anIndexedSeq.

Attributes

Returns: This collection as anIndexedSeq[A].
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

deftoList:List[A]

Implicitly added byoption2Iterable

Converts this collection to aList.

Attributes

Returns: This collection as aList[A].
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

deftoMap[K,V](implicitev:A<:< (K,V)):Map[K,V]

Implicitly added byoption2Iterable

Converts this collection to aMap, given an implicit coercion from the collection's type to a key-value tuple.

Type parameters

K: The key type for the resulting map.
V: The value type for the resulting map.

Value parameters

ev: An implicit coercion fromA to[K, V].

Attributes

Returns: This collection as aMap[K, V].
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

deftoSeq:Seq[A]

Implicitly added byoption2Iterable

Attributes

Returns: This collection as aSeq[A]. This is equivalent toto(Seq) but might be faster.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

deftoSet[B >:A]:Set[B]

Implicitly added byoption2Iterable

Converts this collection to aSet.

Type parameters

B: The type of elements of the result, a supertype ofA.

Attributes

Returns: This collection as aSet[B].
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

deftoVector:Vector[A]

Implicitly added byoption2Iterable

Converts this collection to aVector.

Attributes

Returns: This collection as aVector[A].
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

deftranspose[B](implicitasIterable:A=>Iterable[B]):Iterable[Iterable[B]]

Implicitly added byoption2Iterable

Transposes this iterable collection of iterable collections into a iterable collection of iterable collections.

The resulting collection's type will be guided by the static type of iterable collection. For example:

val xs = List(           Set(1, 2, 3),           Set(4, 5, 6)).transpose// xs == List(//         List(1, 4),//         List(2, 5),//         List(3, 6))val ys = Vector(           List(1, 2, 3),           List(4, 5, 6)).transpose// ys == Vector(//         Vector(1, 4),//         Vector(2, 5),//         Vector(3, 6))

Note: Even when applied to a view or a lazy collection it will always force the elements.

Type parameters

B: the type of the elements of each iterable collection.

Value parameters

asIterable: an implicit conversion which asserts that the element type of this iterable collection is anIterable.

Attributes

Returns: a two-dimensional iterable collection of iterable collections which has asnth row thenth column of this iterable collection.
Throws: IllegalArgumentExceptionif all collections in this iterable collection are not of the same size.
Inherited from:: IterableOps
Source: Iterable.scala

defunzip[A1,A2](implicitasPair:A=> (A1,A2)): (Iterable[A1],Iterable[A2])

Implicitly added byoption2Iterable

Converts this iterable collection of pairs into two collections of the first and second half of each pair.

val xs = Iterable(           (1, "one"),           (2, "two"),           (3, "three")).unzip// xs == (Iterable(1, 2, 3),//        Iterable(one, two, three))

Type parameters

A1: the type of the first half of the element pairs
A2: the type of the second half of the element pairs

Value parameters

asPair: an implicit conversion which asserts that the element type of this iterable collection is a pair.

Attributes

Returns: a pair of iterable collections, containing the first, respectively second half of each element pair of this iterable collection.
Inherited from:: IterableOps
Source: Iterable.scala

defunzip3[A1,A2,A3](implicitasTriple:A=> (A1,A2,A3)): (Iterable[A1],Iterable[A2],Iterable[A3])

Implicitly added byoption2Iterable

Converts this iterable collection of triples into three collections of the first, second, and third element of each triple.

val xs = Iterable(           (1, "one", '1'),           (2, "two", '2'),           (3, "three", '3')).unzip3// xs == (Iterable(1, 2, 3),//        Iterable(one, two, three),//        Iterable(1, 2, 3))

Type parameters

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

Value parameters

asTriple: an implicit conversion which asserts that the element type of this iterable collection is a triple.

Attributes

Returns: a triple of iterable collections, containing the first, second, respectively third member of each element triple of this iterable collection.
Inherited from:: IterableOps
Source: Iterable.scala

defview:View[A]

Implicitly added byoption2Iterable

A view over the elements of this collection.

Attributes

Inherited from:: IterableOps
Source: Iterable.scala

defwithFilter(p:A=>Boolean):WithFilter[A,Iterable]

Implicitly added byoption2Iterable

Creates a non-strict filter of this iterable collection.

Note: the difference betweenc filter p andc withFilter p is that the former creates a new collection, whereas the latter only restricts the domain of subsequentmap,flatMap,foreach, andwithFilter operations.

Note: might return different results for different runs, unless the underlying collection type is ordered.

Value parameters

p: the predicate used to test elements.

Attributes

Returns: an object of classWithFilter, which supportsmap,flatMap,foreach, andwithFilter operations. All these operations apply to those elements of this iterable collection which satisfy the predicatep.
Inherited from:: IterableOps
Source: Iterable.scala

defzip[B](that:IterableOnce[B]):Iterable[(A,B)]

Implicitly added byoption2Iterable

Returns a iterable collection formed from this iterable collection and another iterable collection by combining corresponding elements in pairs.

Returns a iterable collection formed from this iterable collection and another iterable collection by combining corresponding elements in pairs. If one of the two collections is longer than the other, its remaining elements are ignored.

Type parameters

B: the type of the second half of the returned pairs

Value parameters

that: The iterable providing the second half of each result pair

Attributes

Returns: a new iterable collection containing pairs consisting of corresponding elements of this iterable collection andthat. The length of the returned collection is the minimum of the lengths of this iterable collection andthat.
Inherited from:: IterableOps
Source: Iterable.scala

defzipAll[A1 >:A,B](that:Iterable[B],thisElem:A1,thatElem:B):Iterable[(A1,B)]

Implicitly added byoption2Iterable

Returns a iterable collection formed from this iterable collection and another iterable collection by combining corresponding elements in pairs.

Returns a iterable collection formed from this iterable collection and another iterable collection by combining corresponding elements in pairs. If one of the two collections is shorter than the other, placeholder elements are used to extend the shorter collection to the length of the longer.

Value parameters

that: the iterable providing the second half of each result pair
thatElem: the element to be used to fill up the result ifthat is shorter than this iterable collection.
thisElem: the element to be used to fill up the result if this iterable collection is shorter thanthat.

Attributes

Returns: a new collection of the type of this iterable collection containing pairs consisting of corresponding elements of this iterable collection andthat. The length of the returned collection is the maximum of the lengths of this iterable collection andthat. If this iterable collection is shorter thanthat,thisElem values are used to pad the result. Ifthat is shorter than this iterable collection,thatElem values are used to pad the result.
Inherited from:: IterableOps
Source: Iterable.scala

defzipWithIndex:Iterable[(A,Int)]

Implicitly added byoption2Iterable

Zips this iterable collection with its indices.

Attributes

Returns: A new iterable collection containing pairs consisting of all elements of this iterable collection paired with their index. Indices start at0.
Example: List("a", "b", "c").zipWithIndex == List(("a", 0), ("b", 1), ("c", 2))
Inherited from:: IterableOps
Source: Iterable.scala

Inherited and Abstract methods

defcanEqual(that:Any):Boolean

Checks whether this instance can possibly equalthat.

A method that should be called from every well-designed equals method that is open to be overridden in a subclass. SeeProgramming in Scala, Chapter 28 for discussion and design.

Value parameters

that: the value being probed for possible equality

Attributes

Returns: true if this instance can possibly equalthat, otherwise false
Inherited from:: Equals
Source: Equals.scala

defiterator:Iterator[A]

Implicitly added byoption2Iterable

Anscala.collection.Iterator over the elements of this collection.

If anIterableOnce object is in fact anscala.collection.Iterator, this method always returns itself, in its current state, but if it is anscala.collection.Iterable, this method always returns a newscala.collection.Iterator.

Attributes

Inherited from:: IterableOnce
Source: IterableOnce.scala

defproductArity:Int

The size of this product.

Attributes

Returns: for a productA(x1, ..., xk), returnsk
Inherited from:: Product
Source: Product.scala

defproductElement(n:Int):Any

The nth element of this product, 0-based.

The nth element of this product, 0-based. In other words, for a productA(x1, ..., xk), returnsx(n+1) where0 <= n < k.

Value parameters

n: the index of the element to return

Attributes

Returns: the elementn elements after the first element
Throws: IndexOutOfBoundsExceptionif then is out of range(n < 0 || n >= productArity).
Inherited from:: Product
Source: Product.scala

Deprecated and Inherited methods

def++:[B >:A](that:IterableOnce[B]):Iterable[B]

Implicitly added byoption2Iterable

Attributes

Deprecated: [Since version 2.13.0]Use ++ instead of ++: for collections of type Iterable
Inherited from:: IterableOps
Source: Iterable.scala

finaldef/:[B](z:B)(op: (B,A)=>B):B

Implicitly added byoption2Iterable

Attributes

Deprecated: [Since version 2.13.0]Use foldLeft instead of /:
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

finaldef:\[B](z:B)(op: (A,B)=>B):B

Implicitly added byoption2Iterable

Attributes

Deprecated: [Since version 2.13.0]Use foldRight instead of :\\
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defaggregate[B](z:=>B)(seqop: (B,A)=>B,combop: (B,B)=>B):B

Implicitly added byoption2Iterable

Aggregates the results of applying an operator to subsequent elements.

Since this method degenerates tofoldLeft for sequential (non-parallel) collections, where the combining operation is ignored, it is advisable to preferfoldLeft for that case.

Forparallel collections, use theaggregate method specified byscala.collection.parallel.ParIterableLike.

Type parameters

B: the result type, produced byseqop,combop, and by this function as a final result.

Value parameters

combop: an associative operator for combining sequential results, unused for sequential collections.
seqop: the binary operator used to accumulate the result.
z: the start value, a neutral element forseqop.

Attributes

Deprecated: [Since version 2.13.0]For sequential collections, prefer `foldLeft(z)(seqop)`. For parallel collections, use `ParIterableLike#aggregate`.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defcompanion:IterableFactory[Iterable]

Implicitly added byoption2Iterable

Attributes

Deprecated: [Since version 2.13.0]Use iterableFactory instead
Inherited from:: IterableOps
Source: Iterable.scala

finaldefcopyToBuffer[B >:A](dest:Buffer[B]):Unit

Implicitly added byoption2Iterable

Attributes

Deprecated: [Since version 2.13.0]Use `dest ++= coll` instead
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

defhasDefiniteSize:Boolean

Implicitly added byoption2Iterable

Tests whether this collection is known to have a finite size.

Tests whether this collection is known to have a finite size. All strict collections are known to have finite size. For a non-strict collection such asStream, the predicate returnstrue if all elements have been computed. It returnsfalse if the stream is not yet evaluated to the end. Non-empty Iterators usually returnfalse even 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 thathasDefiniteSize returnstrue. However, checkinghasDefiniteSize can provide an assurance that size is well-defined and non-termination is not a concern.

Attributes

Returns: true if this collection is known to have finite size,false otherwise.
See also: methodknownSize for a more useful alternative
Deprecated: [Since version 2.13.0]Check .knownSize instead of .hasDefiniteSize for more actionable information (see scaladoc for details)
This method is deprecated in 2.13 because it does not provide any actionable information. As noted above, even the collection library itself does not use it. When there is no guarantee that a collection is finite, it is generally best to attempt a computation anyway and document that it will not terminate for infinite collections rather than backing out because this would prevent performing the computation on collections that are in fact finite even thoughhasDefiniteSize returnsfalse.
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

finaldefrepr:Iterable[A]

Implicitly added byoption2Iterable

Attributes

Deprecated: [Since version 2.13.0]Use coll instead of repr in a collection implementation, use the collection value itself from the outside
Inherited from:: IterableOps
Source: Iterable.scala

finaldeftoIterator:Iterator[A]

Implicitly added byoption2Iterable

Attributes

Deprecated: [Since version 2.13.0]Use .iterator instead of .toIterator
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

finaldeftoStream:Stream[A]

Implicitly added byoption2Iterable

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Deprecated: [Since version 2.13.0]Use .to(LazyList) instead of .toStream
Inherited from:: IterableOnceOps
Source: IterableOnce.scala

finaldeftoTraversable:Iterable[A]

Implicitly added byoption2Iterable

Converts this iterable collection to an unspecified Iterable.

Converts this iterable collection to an unspecified Iterable. Will return the same collection if this instance is already Iterable.

Attributes

Returns: An Iterable containing all elements of this iterable collection.
Deprecated: [Since version 2.13.0]toTraversable is internal and will be made protected; its name is similar to `toList` or `toSeq`, but it doesn\'t copy non-immutable collections
Inherited from:: IterableOps
Source: Iterable.scala

defview(from:Int,until:Int):View[A]

Implicitly added byoption2Iterable

A view over a slice of the elements of this collection.

Attributes

Deprecated: [Since version 2.13.0]Use .view.slice(from, until) instead of .view(from, until)
Inherited from:: IterableOps
Source: Iterable.scala

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