Option

scala.Option
See theOption companion object
sealed abstract class Option[+A] extends IterableOnce[A] with Product with Serializable

Represents optional values. Instances of Option 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 use map,flatMap, filter, or foreach:

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 upper
println(upper getOrElse "")

Because of how for comprehension works, if $none is returned from request.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
trait Product
trait Equals
trait IterableOnce[A]
class Object
trait Matchable
class Any
Known subtypes
object None.type
class Some[A]
Self type

Members list

Concise view

Type members

Classlikes

class WithFilter(p: 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.

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
Graph
Supertypes
class Object
trait Matchable
class Any

Value members

Abstract methods

def get: A

Returns the option's value.

Returns the option's value.

This is equivalent to:

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

Attributes

Throws:

NoSuchElementException if the option is empty.

Note:

The option must be nonempty.

Source:
Option.scala

Concrete methods

final def collect[B](pf: PartialFunction[A, B]): Option[B]

Returns a scala.Some containing the result of applying pf to this scala.Option's contained value, if this option is nonempty and pf is defined for that value.

Returns a scala.Some containing the result of applying pf to this scala.Option's contained value, if this option is nonempty and pf is defined for that value. Returns None otherwise.

Attributes

pf

the partial function.

Returns:

the result of applying pf to this scala.Option's value (if possible), or None.

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
final def contains[A1 >: A](elem: A1): Boolean

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

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
}

Attributes

elem

the element to test.

Returns:

true if the option has an element that is equal (as determined by ==) to elem, 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
final def exists(p: A => Boolean): Boolean

Returns true if this option is nonempty and the predicate p returns true when applied to this scala.Option's value.

Returns true if this option is nonempty and the predicate p returns true when applied to this scala.Option's value. Otherwise, returns false.

This is equivalent to:

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

Attributes

p

the predicate to test

Source:
Option.scala
final def filter(p: A => Boolean): Option[A]

Returns this scala.Option if it is nonempty and applying the predicate p to this scala.Option's value returns true.

Returns this scala.Option if it is nonempty and applying the predicate p to this scala.Option's value returns true. Otherwise, return None.

This is equivalent to:

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

Attributes

p

the predicate used for testing.

Source:
Option.scala
final def filterNot(p: A => Boolean): Option[A]

Returns this scala.Option if it is nonempty and applying the predicate p to this scala.Option's value returns false.

Returns this scala.Option if it is nonempty and applying the predicate p to this scala.Option's value returns false. Otherwise, return None.

This is equivalent to:

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

Attributes

p

the predicate used for testing.

Source:
Option.scala
final def flatMap[B](f: A => Option[B]): Option[B]

Returns the result of applying f to this scala.Option's value if this scala.Option is nonempty.

Returns the result of applying f to this scala.Option's value if this scala.Option is nonempty. Returns None if this scala.Option is empty. Slightly different from map in that f is expected to return an scala.Option (which could be None).

This is equivalent to:

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

Attributes

f

the function to apply

See also:

map

foreach

Source:
Option.scala
def flatten[B](implicit ev: A <:< Option[B]): Option[B]

Returns the nested scala.Option value if it is nonempty.

Returns the nested scala.Option value if it is nonempty. Otherwise, return None.

This is equivalent to:

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

Attributes

ev

an implicit conversion that asserts that the value is also an scala.Option.

See also:

flatMap

Example:

Some(Some("something")).flatten
Source:
Option.scala
final def fold[B](ifEmpty: => B)(f: A => B): B

Returns the result of applying f to this scala.Option's value if the scala.Option is nonempty.

Returns the result of applying f to this scala.Option's value if the scala.Option is nonempty. Otherwise, evaluates expression ifEmpty.

This is equivalent to:

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

This is also equivalent to:

option map f getOrElse ifEmpty

Attributes

f

the function to apply if nonempty.

ifEmpty

the expression to evaluate if empty.

Source:
Option.scala
final def forall(p: A => Boolean): Boolean

Returns true if this option is empty or the predicate p returns true when applied to this scala.Option's value.

Returns true if this option is empty or the predicate p returns true when applied to this scala.Option's value.

This is equivalent to:

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

Attributes

p

the predicate to test

Source:
Option.scala
final def foreach[U](f: A => U): Unit

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

Apply the given procedure f 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    => ()
}

Attributes

f

the procedure to apply.

See also:

map

flatMap

Source:
Option.scala
final def getOrElse[B >: A](default: => B): B

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

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

This is equivalent to:

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

Attributes

default

the default expression.

Source:
Option.scala
final def isDefined: Boolean

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

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

This is equivalent to:

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

Attributes

Source:
Option.scala
final def isEmpty: Boolean

Returns true if the option is None, false otherwise.

Returns true if the option is None, false otherwise.

This is equivalent to:

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

Attributes

Source:
Option.scala
Implicitly added by option2Iterable

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

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

Attributes

Note:

When implementing a custom collection type and refining CC to the new type, this method needs to be overridden to return a factory for the new type (the compiler will issue an error otherwise).

Source:
Iterable.scala

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

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

Attributes

Source:
Option.scala
final override def knownSize: Int

Attributes

Returns:

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

Definition Classes
Source:
Option.scala
def lazyZip[B](that: Iterable[B]): LazyZip2[A, B, Iterable]
Implicitly added by option2Iterable

Analogous to zip except that the elements in each collection are not consumed until a strict operation is invoked on the returned LazyZip2 decorator.

Analogous to zip except that the elements in each collection are not consumed until a strict operation is invoked on the returned LazyZip2 decorator.

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

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

Attributes

B

the type of the second element in each eventual pair

that

the iterable providing the second element of each eventual pair

Returns:

a decorator LazyZip2 that allows strict operations to be performed on the lazily evaluated pairs or chained calls to lazyZip. Implicit conversion to Iterable[(A, B)] is also supported.

Source:
Iterable.scala
final def map[B](f: A => B): Option[B]

Returns a scala.Some containing the result of applying f to this scala.Option's value if this scala.Option is nonempty.

Returns a scala.Some containing the result of applying f to this scala.Option's value if this scala.Option is nonempty. Otherwise return None.

This is equivalent to:

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

Attributes

f

the function to apply

See also:

flatMap

foreach

Note:

This is similar to flatMap except here, f does not need to wrap its result in an scala.Option.

Source:
Option.scala
final def nonEmpty: Boolean

Returns false if the option is None, true otherwise.

Returns false if the option is None, 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
final def orElse[B >: A](alternative: => Option[B]): Option[B]

Returns this scala.Option if it is nonempty, otherwise return the result of evaluating alternative.

Returns this scala.Option if it is nonempty, otherwise return the result of evaluating alternative.

This is equivalent to:

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

Attributes

alternative

the alternative expression.

Source:
Option.scala
final def orNull[A1 >: A](implicit ev: Null <:< A1): A1

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

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

Although the use of null is discouraged, code written to use scala.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] = getInitialText
val textField = new JComponent(initialText.orNull,20)
Source:
Option.scala
final def toLeft[X](right: => X): Either[A, X]

Returns a scala.util.Right containing the given argument right if this is empty, or a scala.util.Left containing this scala.Option's value if this scala.Option is nonempty.

Returns a scala.util.Right containing the given argument right if this is empty, or a scala.util.Left containing this scala.Option's value if this scala.Option is nonempty.

This is equivalent to:

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

Attributes

right

the expression to evaluate and return if this is empty

See also:

toRight

Source:
Option.scala
def toList: List[A]

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

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

This is equivalent to:

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

Attributes

Source:
Option.scala
final def toRight[X](left: => X): Either[X, A]

Returns a scala.util.Left containing the given argument left if this scala.Option is empty, or a scala.util.Right containing this scala.Option's value if this is nonempty.

Returns a scala.util.Left containing the given argument left if this scala.Option is empty, or a scala.util.Right containing this scala.Option's value if this is nonempty.

This is equivalent to:

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

Attributes

left

the expression to evaluate and return if this is empty

See also:

toLeft

Source:
Option.scala
final def unzip[A1, A2](implicit asPair: 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.

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)
}

Attributes

A1

the type of the first half of the element pair

A2

the type of the second half of the element pair

asPair

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

Returns:

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

Source:
Option.scala
final def unzip3[A1, A2, A3](implicit asTriple: 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.

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)
}

Attributes

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

asTriple

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

Returns:

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

Source:
Option.scala
final def withFilter(p: A => Boolean): WithFilter

Necessary to keep scala.Option from being implicitly converted to scala.collection.Iterable in for comprehensions.

Necessary to keep scala.Option from being implicitly converted to scala.collection.Iterable in for comprehensions.

Attributes

Source:
Option.scala
final def zip[A1 >: A, B](that: Option[B]): Option[(A1, B)]

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

Returns a scala.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
}

Attributes

that

the options which is going to be zipped

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

def seq: Iterable.this.type
Implicitly added by option2Iterable

Attributes

Deprecated
true
Source:
Iterable.scala
final def toIterable: Iterable.this.type
Implicitly added by option2Iterable

Attributes

Returns:

This collection as an Iterable[A]. No new collection will be built if this is already an Iterable[A].

Deprecated
true
Source:
Iterable.scala

Inherited methods

final def ++[B >: A](suffix: IterableOnce[B]): CC[B]
Implicitly added by option2Iterable

Alias for concat

Alias for concat

Attributes

Inherited from:
IterableOps
Source:
Iterable.scala
Implicitly added by option2Iterable

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 method toString) of all elements of this collection without any separator string.

Example:

scala> val a = List(1,2,3,4)
a: List[Int] = List(1, 2, 3, 4)

scala> val b = new StringBuilder()
b: StringBuilder =

scala> val h = a.addString(b)
h: StringBuilder = 1234

Attributes

b

the string builder to which elements are appended.

Returns:

the string builder b to which elements were appended.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
Implicitly added by option2Iterable

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 method toString) of all elements of this collection, separated by the string sep.

Example:

scala> val a = List(1,2,3,4)
a: List[Int] = List(1, 2, 3, 4)

scala> val b = new StringBuilder()
b: StringBuilder =

scala> a.addString(b, ", ")
res0: StringBuilder = 1, 2, 3, 4

Attributes

b

the string builder to which elements are appended.

sep

the separator string.

Returns:

the string builder b to which elements were appended.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
Implicitly added by option2Iterable

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 string start and ends with the string end. Inside, the string representations (w.r.t. the method toString) of all elements of this collection are separated by the string sep.

Example:

scala> val a = List(1,2,3,4)
a: List[Int] = List(1, 2, 3, 4)

scala> val b = new StringBuilder()
b: StringBuilder =

scala> a.addString(b , "List(" , ", " , ")")
res5: StringBuilder = List(1, 2, 3, 4)

Attributes

b

the string builder to which elements are appended.

end

the ending string.

sep

the separator string.

start

the starting string.

Returns:

the string builder b to which elements were appended.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def canEqual(that: Any): Boolean

A method that should be called from every well-designed equals method that is open to be overridden in a subclass.

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

Attributes

that

the value being probed for possible equality

Returns:

true if this instance can possibly equal that, otherwise false

Inherited from:
Equals
Source:
Equals.scala
def collect[B](pf: PartialFunction[A, B]): CC[B]
Implicitly added by option2Iterable

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

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

Attributes

B

the element type of the returned iterable collection.

pf

the partial function which filters and maps the iterable collection.

Returns:

a new iterable collection resulting from applying the given partial function pf to each element on which it is defined and collecting the results. The order of the elements is preserved.

Inherited from:
IterableOps
Source:
Iterable.scala
def collectFirst[B](pf: PartialFunction[A, B]): Option[B]
Implicitly added by option2Iterable

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

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.

Attributes

pf

the partial function

Returns:

an option value containing pf applied to the first value for which it is defined, or None if none exists.

Example:

Seq("a", 1, 5L).collectFirst({ case x: Int => x*10 }) = Some(10)

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def concat[B >: A](suffix: IterableOnce[B]): CC[B]
Implicitly added by option2Iterable

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.

Attributes

B

the element type of the returned collection.

suffix

the iterable to append.

Returns:

a new iterable collection which contains all elements of this iterable collection followed by all elements of suffix.

Inherited from:
IterableOps
Source:
Iterable.scala
def copyToArray[B >: A](xs: Array[B], start: Int, len: Int): Int
Implicitly added by option2Iterable

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 xs starting at index start with at most len elements of this collection.

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

Attributes

B

the type of the elements of the array.

len

the maximal number of elements to copy.

start

the starting index of xs.

xs

the array to fill.

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
def copyToArray[B >: A](xs: Array[B], start: Int): Int
Implicitly added by option2Iterable

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 xs starting at index start with values of this collection.

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

Attributes

B

the type of the elements of the array.

start

the starting index of xs.

xs

the array to fill.

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
def copyToArray[B >: A](xs: Array[B]): Int
Implicitly added by option2Iterable

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 xs starting at index start with values of this collection.

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

Attributes

B

the type of the elements of the array.

xs

the array to fill.

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
def corresponds[B](that: IterableOnce[B])(p: (A, B) => Boolean): Boolean
Implicitly added by option2Iterable

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.

Attributes

B

the type of the elements of that

p

the test predicate, which relates elements from both collections

that

the other collection

Returns:

true if both collections have the same length and p(x, y) is true for all corresponding elements x of this iterator and y of that, otherwise false

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def count(p: A => Boolean): Int
Implicitly added by option2Iterable

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

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

Note: will not terminate for infinite-sized collections.

Attributes

p

the predicate used to test elements.

Returns:

the number of elements satisfying the predicate p.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def drop(n: Int): C
Implicitly added by option2Iterable

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.

Attributes

n

the number of elements to drop from this iterable collection.

Returns:

a iterable collection consisting of all elements of this iterable collection except the first n ones, or else the empty iterable collection, if this iterable collection has less than n elements. If n is negative, don't drop any elements.

Inherited from:
IterableOps
Source:
Iterable.scala
def dropRight(n: Int): C
Implicitly added by option2Iterable

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.

Attributes

n

the number of elements to drop from this iterable collection.

Returns:

a iterable collection consisting of all elements of this iterable collection except the last n ones, or else the empty iterable collection, if this iterable collection has less than n elements. If n is negative, don't drop any elements.

Inherited from:
IterableOps
Source:
Iterable.scala
def dropWhile(p: A => Boolean): C
Implicitly added by option2Iterable

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.

Attributes

p

The predicate used to test elements.

Returns:

the longest suffix of this iterable collection whose first element does not satisfy the predicate p.

Inherited from:
IterableOps
Source:
Iterable.scala
def exists(p: A => Boolean): Boolean
Implicitly added by option2Iterable

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

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

Note: may not terminate for infinite-sized collections.

Attributes

p

the predicate used to test elements.

Returns:

true if the given predicate p is satisfied by at least one element of this collection, otherwise false

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def filter(pred: A => Boolean): C
Implicitly added by option2Iterable

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

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

Attributes

p

the predicate used to test elements.

Returns:

a new iterable collection consisting of all elements of this iterable collection that satisfy the given predicate p. The order of the elements is preserved.

Inherited from:
IterableOps
Source:
Iterable.scala
def filterNot(pred: A => Boolean): C
Implicitly added by option2Iterable

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

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

Attributes

pred

the predicate used to test elements.

Returns:

a new iterable collection consisting of all elements of this iterable collection that do not satisfy the given predicate pred. Their order may not be preserved.

Inherited from:
IterableOps
Source:
Iterable.scala
def find(p: A => Boolean): Option[A]
Implicitly added by option2Iterable

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

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.

Attributes

p

the predicate used to test elements.

Returns:

an option value containing the first element in the collection that satisfies p, or None if none exists.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def flatMap[B](f: A => IterableOnce[B]): CC[B]
Implicitly added by option2Iterable

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

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

For example:

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

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

// lettersOf will return a Seq[Char] of likely repeated letters, instead of a Set
def lettersOf(words: Seq[String]) = words flatMap (word => word.toSet)

// lettersOf will return a Set[Char], not a Seq
def lettersOf(words: Seq[String]) = words.toSet flatMap ((word: String) => word.toSeq)

// xs will be an Iterable[Int]
val xs = Map("a" -> List(11,111), "b" -> List(22,222)).flatMap(_._2)

// ys will be a Map[Int, Int]
val ys = Map("a" -> List(1 -> 11,1 -> 111), "b" -> List(2 -> 22,2 -> 222)).flatMap(_._2)

Attributes

B

the element type of the returned collection.

f

the function to apply to each element.

Returns:

a new iterable collection resulting from applying the given collection-valued function f to each element of this iterable collection and concatenating the results.

Inherited from:
IterableOps
Source:
Iterable.scala
def flatten[B](implicit asIterable: A => IterableOnce[B]): CC[B]
Implicitly added by option2Iterable

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

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)

Attributes

B

the type of the elements of each iterable collection.

asIterable

an implicit conversion which asserts that the element type of this iterable collection is an Iterable.

Returns:

a new iterable collection resulting from concatenating all element iterable collections.

Inherited from:
IterableOps
Source:
Iterable.scala
def fold[A1 >: A](z: A1)(op: (A1, A1) => A1): A1
Implicitly added by option2Iterable

Folds the elements of this collection using the specified associative binary operator.

Folds the elements of this collection using the specified associative binary operator. The default implementation in IterableOnce is equivalent to foldLeft but may be overridden for more efficient traversal orders.

The order in which operations are performed on elements is unspecified and may be nondeterministic.

Note: will not terminate for infinite-sized collections.

Attributes

A1

a type parameter for the binary operator, a supertype of A.

op

a binary operator that must be associative.

z

a neutral element for the fold operation; may be added to the result an arbitrary number of times, and must not change the result (e.g., Nil for list concatenation, 0 for addition, or 1 for multiplication).

Returns:

the result of applying the fold operator op between all the elements and z, or z if this collection is empty.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def foldLeft[B](z: B)(op: (B, A) => B): B
Implicitly added by option2Iterable

Applies a binary operator to a start value and all elements of this collection, going left to right.

Applies a binary operator to a start value and all elements of this collection, going left to right.

Note: will not terminate for infinite-sized collections.

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

Attributes

B

the result type of the binary operator.

op

the binary operator.

z

the start value.

Returns:

the result of inserting op between consecutive elements of this collection, going left to right with the start value z on the left: op(...op(z, x1), x2, ..., xn) where x1, ..., xn are the elements of this collection. Returns z if this collection is empty.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def foldRight[B](z: B)(op: (A, B) => B): B
Implicitly added by option2Iterable

Applies a binary operator to all elements of this collection and a start value, going right to left.

Applies a binary operator to all elements of this collection and a start value, going right to left.

Note: will not terminate for infinite-sized collections.

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

Attributes

B

the result type of the binary operator.

op

the binary operator.

z

the start value.

Returns:

the result of inserting op between consecutive elements of this collection, going right to left with the start value z on the right: op(x1, op(x2, ... op(xn, z)...)) where x1, ..., xn are the elements of this collection. Returns z if this collection is empty.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def forall(p: A => Boolean): Boolean
Implicitly added by option2Iterable

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

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

Note: may not terminate for infinite-sized collections.

Attributes

p

the predicate used to test elements.

Returns:

true if this collection is empty or the given predicate p holds for all elements of this collection, otherwise false.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def foreach[U](f: A => U): Unit
Implicitly added by option2Iterable

Apply f to each element for its side effects Note: [U] parameter needed to help scalac's type inference.

Apply f to each element for its side effects Note: [U] parameter needed to help scalac's type inference.

Attributes

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
protected def fromSpecific(coll: IterableOnce[A]): CC[A]
Implicitly added by option2Iterable

Defines how to turn a given Iterable[A] into a collection of type C.

Defines how to turn a given Iterable[A] into a collection of type C.

This process can be done in a strict way or a non-strict way (ie. without evaluating the elements of the resulting collections). In other words, this methods defines the evaluation model of the collection.

Attributes

Note:

When implementing a custom collection type and refining C to the new type, this method needs to be overridden (the compiler will issue an error otherwise). In the common case where C =:= CC[A], this can be done by mixing in the scala.collection.IterableFactoryDefaults trait, which implements the method using iterableFactory.

As witnessed by the @uncheckedVariance annotation, using this method might be unsound. However, as long as it is called with an Iterable[A] obtained from this collection (as it is the case in the implementations of operations where we use a View[A]), it is safe.

Inherited from:
IterableFactoryDefaults
Source:
Iterable.scala
def groupBy[K](f: A => K): Map[K, C]
Implicitly added by option2Iterable

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

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.

Attributes

K

the type of keys returned by the discriminator function.

f

the discriminator function.

Returns:

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

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

That is, every key k is bound to a iterable collection of those elements x for which f(x) equals k.

Inherited from:
IterableOps
Source:
Iterable.scala
def groupMap[K, B](key: A => K)(f: A => B): Map[K, CC[B]]
Implicitly added by option2Iterable

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

Partitions this iterable collection into a map of iterable collections according to a discriminator function key. Each element in a group is transformed into a value of type B using the value function.

It is equivalent to groupBy(key).mapValues(_.map(f)), but more efficient.

case class User(name: String, age: Int)

def namesByAge(users: Seq[User]): Map[Int, Seq[String]] =
  users.groupMap(_.age)(_.name)

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

Attributes

B

the type of values returned by the transformation function

K

the type of keys returned by the discriminator function

f

the element transformation function

key

the discriminator function

Inherited from:
IterableOps
Source:
Iterable.scala
def groupMapReduce[K, B](key: A => K)(f: A => B)(reduce: (B, B) => B): Map[K, B]
Implicitly added by option2Iterable

Partitions this iterable collection into a map according to a discriminator function key.

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

It is equivalent to groupBy(key).mapValues(_.map(f).reduce(reduce)), but more efficient.

def occurrences[A](as: Seq[A]): Map[A, Int] =
  as.groupMapReduce(identity)(_ => 1)(_ + _)

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

Attributes

Inherited from:
IterableOps
Source:
Iterable.scala
def grouped(size: Int): Iterator[C]
Implicitly added by option2Iterable

Partitions elements in fixed size iterable collections.

Partitions elements in fixed size iterable collections.

Attributes

size

the number of elements per group

Returns:

An iterator producing iterable collections of size size, except the last will be less than size size if the elements don't divide evenly.

See also:
Inherited from:
IterableOps
Source:
Iterable.scala
def head: A
Implicitly added by option2Iterable

Selects the first element of this iterable collection.

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:

NoSuchElementException if the iterable collection is empty.

Inherited from:
IterableOps
Source:
Iterable.scala
Implicitly added by option2Iterable

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.

Attributes

Returns:

the first element of this iterable collection if it is nonempty, None if it is empty.

Inherited from:
IterableOps
Source:
Iterable.scala
def init: C
Implicitly added by option2Iterable

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.

Attributes

Inherited from:
IterableOps
Source:
Iterable.scala
def inits: Iterator[C]
Implicitly added by option2Iterable

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 of init.

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
Implicitly added by option2Iterable

Tests whether the collection is empty.

Tests whether the collection is empty.

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

Attributes

Returns:

true if the collection contains no elements, false otherwise.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
Implicitly added by option2Iterable

Iterator can be used only once

Iterator can be used only once

Attributes

Inherited from:
IterableOnce
Source:
IterableOnce.scala
Implicitly added by option2Iterable

Attributes

Returns:

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

Inherited from:
IterableOnce
Source:
IterableOnce.scala
def last: A
Implicitly added by option2Iterable

Selects the last element.

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:

NoSuchElementException If the iterable collection is empty.

Inherited from:
IterableOps
Source:
Iterable.scala
Implicitly added by option2Iterable

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.

Attributes

Returns:

the last element of this iterable collection$ if it is nonempty, None if it is empty.

Inherited from:
IterableOps
Source:
Iterable.scala
def map[B](f: A => B): CC[B]
Implicitly added by option2Iterable

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

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

Attributes

B

the element type of the returned iterable collection.

f

the function to apply to each element.

Returns:

a new iterable collection resulting from applying the given function f to each element of this iterable collection and collecting the results.

Inherited from:
IterableOps
Source:
Iterable.scala
def max[B >: A](implicit ord: Ordering[B]): A
Implicitly added by option2Iterable

Finds the largest element.

Finds the largest element.

Note: will not terminate for infinite-sized collections.

Attributes

B

The type over which the ordering is defined.

ord

An ordering to be used for comparing elements.

Returns:

the largest element of this collection with respect to the ordering ord.

Throws:

UnsupportedOperationException if this collection is empty.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def maxBy[B](f: A => B)(implicit cmp: Ordering[B]): A
Implicitly added by option2Iterable

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.

Attributes

B

The result type of the function f.

cmp

An ordering to be used for comparing elements.

f

The measuring function.

Returns:

the first element of this collection with the largest value measured by function f with respect to the ordering cmp.

Throws:

UnsupportedOperationException if this collection is empty.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def maxByOption[B](f: A => B)(implicit cmp: Ordering[B]): Option[A]
Implicitly added by option2Iterable

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.

Attributes

B

The result type of the function f.

cmp

An ordering to be used for comparing elements.

f

The measuring function.

Returns:

an option value containing the first element of this collection with the largest value measured by function f with respect to the ordering cmp.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def maxOption[B >: A](implicit ord: Ordering[B]): Option[A]
Implicitly added by option2Iterable

Finds the largest element.

Finds the largest element.

Note: will not terminate for infinite-sized collections.

Attributes

B

The type over which the ordering is defined.

ord

An ordering to be used for comparing elements.

Returns:

an option value containing the largest element of this collection with respect to the ordering ord.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def min[B >: A](implicit ord: Ordering[B]): A
Implicitly added by option2Iterable

Finds the smallest element.

Finds the smallest element.

Note: will not terminate for infinite-sized collections.

Attributes

B

The type over which the ordering is defined.

ord

An ordering to be used for comparing elements.

Returns:

the smallest element of this collection with respect to the ordering ord.

Throws:

UnsupportedOperationException if this collection is empty.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def minBy[B](f: A => B)(implicit cmp: Ordering[B]): A
Implicitly added by option2Iterable

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.

Attributes

B

The result type of the function f.

cmp

An ordering to be used for comparing elements.

f

The measuring function.

Returns:

the first element of this collection with the smallest value measured by function f with respect to the ordering cmp.

Throws:

UnsupportedOperationException if this collection is empty.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def minByOption[B](f: A => B)(implicit cmp: Ordering[B]): Option[A]
Implicitly added by option2Iterable

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.

Attributes

B

The result type of the function f.

cmp

An ordering to be used for comparing elements.

f

The measuring function.

Returns:

an option value containing the first element of this collection with the smallest value measured by function f with respect to the ordering cmp.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def minOption[B >: A](implicit ord: Ordering[B]): Option[A]
Implicitly added by option2Iterable

Finds the smallest element.

Finds the smallest element.

Note: will not terminate for infinite-sized collections.

Attributes

B

The type over which the ordering is defined.

ord

An ordering to be used for comparing elements.

Returns:

an option value containing the smallest element of this collection with respect to the ordering ord.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
final def mkString: String
Implicitly added by option2Iterable

Displays all elements of this collection in a string.

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 method toString) of all elements of this collection follow each other without any separator string.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
final def mkString(sep: String): String
Implicitly added by option2Iterable

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

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

Delegates to addString, which can be overridden.

Attributes

sep

the separator string.

Returns:

a string representation of this collection. In the resulting string the string representations (w.r.t. the method toString) of all elements of this collection are separated by the string sep.

Example:

List(1, 2, 3).mkString("|") = "1|2|3"

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
final def mkString(start: String, sep: String, end: String): String
Implicitly added by option2Iterable

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

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

Delegates to addString, which can be overridden.

Attributes

end

the ending string.

sep

the separator string.

start

the starting string.

Returns:

a string representation of this collection. The resulting string begins with the string start and ends with the string end. Inside, the string representations (w.r.t. the method toString) of all elements of this collection are separated by the string sep.

Example:

List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
protected def newSpecificBuilder: Builder[A, CC[A]]
Implicitly added by option2Iterable

Attributes

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 Builder will break laziness. As a consequence, operations should preferably be implemented with fromSpecific instead of this method.

Note:

When implementing a custom collection type and refining C to the new type, this method needs to be overridden (the compiler will issue an error otherwise). In the common case where C =:= CC[A], this can be done by mixing in the scala.collection.IterableFactoryDefaults trait, which implements the method using iterableFactory.

As witnessed by the @uncheckedVariance annotation, using this method might be unsound. However, as long as the returned builder is only fed with A values taken from this instance, it is safe.

Inherited from:
IterableFactoryDefaults
Source:
Iterable.scala
Implicitly added by option2Iterable

Tests whether the collection is not empty.

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
def partition(p: A => Boolean): (C, C)
Implicitly added by option2Iterable

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

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

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

Attributes

Inherited from:
IterableOps
Source:
Iterable.scala
def partitionMap[A1, A2](f: A => Either[A1, A2]): (CC[A1], CC[A2])
Implicitly added by option2Iterable

Applies a function f to each element of the iterable collection and returns a pair of iterable collections: the first one made of those values returned by f that were wrapped in scala.util.Left, and the second one made of those wrapped in scala.util.Right.

Applies a function f to each element of the iterable collection and returns a pair of iterable collections: the first one made of those values returned by f that were wrapped in scala.util.Left, and the second one made of those wrapped in scala.util.Right.

Example:

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

Attributes

A1

the element type of the first resulting collection

A2

the element type of the second resulting collection

f

the 'split function' mapping the elements of this iterable collection to an scala.util.Either

Returns:

a pair of iterable collections: the first one made of those values returned by f that were wrapped in scala.util.Left, and the second one made of those wrapped in scala.util.Right.

Inherited from:
IterableOps
Source:
Iterable.scala
def product[B >: A](implicit num: Numeric[B]): B
Implicitly added by option2Iterable

Multiplies up the elements of this collection.

Multiplies up the elements of this collection.

Note: will not terminate for infinite-sized collections.

Attributes

B

the result type of the * operator.

num

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

Returns:

the product of all elements of this collection with respect to the * operator in num.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala

The size of this product.

The size of this product.

Attributes

Returns:

for a product A(x1, ..., xk), returns k

Inherited from:
Product
Source:
Product.scala

The nth element of this product, 0-based.

The nth element of this product, 0-based. In other words, for a product A(x1, ..., xk), returns x(n+1) where 0 <= n < k.

Attributes

n

the index of the element to return

Returns:

the element n elements after the first element

Throws:

IndexOutOfBoundsException if the n is out of range(n < 0 || n >= productArity).

Inherited from:
Product
Source:
Product.scala

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.

Attributes

n

the index of the element name to return

Returns:

the name of the specified element

Throws:

IndexOutOfBoundsException if the n is out of range(n < 0 || n >= productArity).

Inherited from:
Product
Source:
Product.scala

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

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

Attributes

Inherited from:
Product
Source:
Product.scala

An iterator over all the elements of this product.

An iterator over all the elements of this product.

Attributes

Returns:

in the default implementation, an Iterator[Any]

Inherited from:
Product
Source:
Product.scala

A string used in the toString methods of derived classes.

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

Attributes

Returns:

in the default implementation, the empty string

Inherited from:
Product
Source:
Product.scala
def reduce[B >: A](op: (B, B) => B): B
Implicitly added by option2Iterable

Reduces the elements of this collection using the specified associative binary operator.

Reduces the elements of this collection using the specified associative binary operator.

The order in which operations are performed on elements is unspecified and may be nondeterministic.

Attributes

B

A type parameter for the binary operator, a supertype of A.

op

A binary operator that must be associative.

Returns:

The result of applying reduce operator op between all the elements if the collection is nonempty.

Throws:

UnsupportedOperationException if this collection is empty.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def reduceLeft[B >: A](op: (B, A) => B): B
Implicitly added by option2Iterable

Applies a binary operator to all elements of this collection, going left to right.

Applies a binary operator to all elements of this collection, going left to right.

Note: will not terminate for infinite-sized collections.

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

Attributes

B

the result type of the binary operator.

op

the binary operator.

Returns:

the result of inserting op between consecutive elements of this collection, going left to right: op( op( ... op(x1, x2) ..., xn-1), xn) where x1, ..., xn are the elements of this collection.

Throws:

UnsupportedOperationException if this collection is empty.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def reduceLeftOption[B >: A](op: (B, A) => B): Option[B]
Implicitly added by option2Iterable

Optionally applies a binary operator to all elements of this collection, going left to right.

Optionally applies a binary operator to all elements of this collection, going left to right.

Note: will not terminate for infinite-sized collections.

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

Attributes

B

the result type of the binary operator.

op

the binary operator.

Returns:

an option value containing the result of reduceLeft(op) if this collection is nonempty, None otherwise.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def reduceOption[B >: A](op: (B, B) => B): Option[B]
Implicitly added by option2Iterable

Reduces the elements of this collection, if any, using the specified associative binary operator.

Reduces the elements of this collection, if any, using the specified associative binary operator.

The order in which operations are performed on elements is unspecified and may be nondeterministic.

Attributes

B

A type parameter for the binary operator, a supertype of A.

op

A binary operator that must be associative.

Returns:

An option value containing result of applying reduce operator op between all the elements if the collection is nonempty, and None otherwise.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def reduceRight[B >: A](op: (A, B) => B): B
Implicitly added by option2Iterable

Applies a binary operator to all elements of this collection, going right to left.

Applies a binary operator to all elements of this collection, going right to left.

Note: will not terminate for infinite-sized collections.

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

Attributes

B

the result type of the binary operator.

op

the binary operator.

Returns:

the result of inserting op between consecutive elements of this collection, going right to left: op(x1, op(x2, ..., op(xn-1, xn)...)) where x1, ..., xn are the elements of this collection.

Throws:

UnsupportedOperationException if this collection is empty.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def reduceRightOption[B >: A](op: (A, B) => B): Option[B]
Implicitly added by option2Iterable

Optionally applies a binary operator to all elements of this collection, going right to left.

Optionally applies a binary operator to all elements of this collection, going right to left.

Note: will not terminate for infinite-sized collections.

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

Attributes

B

the result type of the binary operator.

op

the binary operator.

Returns:

an option value containing the result of reduceRight(op) if this collection is nonempty, None otherwise.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
protected def reversed: Iterable[A]
Implicitly added by option2Iterable

Attributes

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def scan[B >: A](z: B)(op: (B, B) => B): CC[B]
Implicitly added by option2Iterable

Computes a prefix scan of the elements of the collection.

Computes a prefix scan of the elements of the collection.

Note: The neutral element z may be applied more than once.

Attributes

B

element type of the resulting collection

op

the associative operator for the scan

z

neutral element for the operator op

Returns:

a new iterable collection containing the prefix scan of the elements in this iterable collection

Inherited from:
IterableOps
Source:
Iterable.scala
def scanLeft[B](z: B)(op: (B, A) => B): CC[B]
Implicitly added by option2Iterable

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

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.

Attributes

B

the type of the elements in the resulting collection

op

the binary operator applied to the intermediate result and the element

z

the initial value

Returns:

collection with intermediate results

Inherited from:
IterableOps
Source:
Iterable.scala
def scanRight[B](z: B)(op: (A, B) => B): CC[B]
Implicitly added by option2Iterable

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)

Attributes

B

the type of the elements in the resulting collection

op

the binary operator applied to the intermediate result and the element

z

the initial value

Returns:

collection with intermediate results

Inherited from:
IterableOps
Source:
Iterable.scala
def size: Int
Implicitly added by option2Iterable

The size of this collection.

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
def sizeCompare(that: Iterable[_]): Int
Implicitly added by option2Iterable

Compares the size of this iterable collection to the size of another Iterable.

Compares the size of this iterable collection to the size of another Iterable.

Attributes

that

the Iterable whose size is compared with this iterable collection's size.

Returns:

A value x where

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

The method as implemented here does not call size directly; its running time is O(this.size min that.size) instead of O(this.size + that.size). The method should be overridden if computing size is cheap and knownSize returns -1.

Inherited from:
IterableOps
Source:
Iterable.scala
def sizeCompare(otherSize: Int): Int
Implicitly added by option2Iterable

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

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

Attributes

otherSize

the test value that gets compared with the size.

Returns:

A value x where

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

The method as implemented here does not call size directly; its running time is O(size min otherSize) instead of O(size). The method should be overridden if computing size is cheap and knownSize returns -1.

See also:
Inherited from:
IterableOps
Source:
Iterable.scala
Implicitly added by option2Iterable

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

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

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

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

Attributes

Inherited from:
IterableOps
Source:
Iterable.scala
def slice(from: Int, until: Int): C
Implicitly added by option2Iterable

Selects an interval of elements.

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

from <= indexOf(x) < until

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

Attributes

from

the lowest index to include from this iterable collection.

until

the lowest index to EXCLUDE from this iterable collection.

Returns:

a iterable collection containing the elements greater than or equal to index from extending up to (but not including) index until of this iterable collection.

Inherited from:
IterableOps
Source:
Iterable.scala
def sliding(size: Int, step: Int): Iterator[C]
Implicitly added by option2Iterable

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.

Attributes

size

the number of elements per group

step

the distance between the first elements of successive groups

Returns:

An iterator producing iterable collections of size size, except the last element (which may be the only element) will be smaller if there are fewer than size elements remaining to be grouped.

See also:
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
def sliding(size: Int): Iterator[C]
Implicitly added by option2Iterable

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.

Attributes

size

the number of elements per group

Returns:

An iterator producing iterable collections of size size, except for a non-empty collection with less than size elements, which returns an iterator that produces the source collection itself as its only element.

See also:
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
def span(p: A => Boolean): (C, C)
Implicitly added by option2Iterable

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

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

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

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

Attributes

p

the test predicate

Returns:

a pair consisting of the longest prefix of this iterable collection whose elements all satisfy p, and the rest of this iterable collection.

Inherited from:
IterableOps
Source:
Iterable.scala
def stepper[S <: Stepper[_]](implicit shape: StepperShape[A, S]): S
Implicitly added by option2Iterable

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.

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.

Attributes

Inherited from:
IterableOnce
Source:
IterableOnce.scala
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.

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.

Attributes

Inherited from:
IterableOnce
Source:
IterableOnce.scala
def sum[B >: A](implicit num: Numeric[B]): B
Implicitly added by option2Iterable

Sums up the elements of this collection.

Sums up the elements of this collection.

Note: will not terminate for infinite-sized collections.

Attributes

B

the result type of the + operator.

num

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

Returns:

the sum of all elements of this collection with respect to the + operator in num.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def tail: C
Implicitly added by option2Iterable

The rest of the collection without its first element.

The rest of the collection without its first element.

Attributes

Inherited from:
IterableOps
Source:
Iterable.scala
def tails: Iterator[C]
Implicitly added by option2Iterable

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 of tail.

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
def take(n: Int): C
Implicitly added by option2Iterable

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.

Attributes

n

the number of elements to take from this iterable collection.

Returns:

a iterable collection consisting only of the first n elements of this iterable collection, or else the whole iterable collection, if it has less than n elements. If n is negative, returns an empty iterable collection.

Inherited from:
IterableOps
Source:
Iterable.scala
def takeRight(n: Int): C
Implicitly added by option2Iterable

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.

Attributes

n

the number of elements to take from this iterable collection.

Returns:

a iterable collection consisting only of the last n elements of this iterable collection, or else the whole iterable collection, if it has less than n elements. If n is negative, returns an empty iterable collection.

Inherited from:
IterableOps
Source:
Iterable.scala
def takeWhile(p: A => Boolean): C
Implicitly added by option2Iterable

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.

Attributes

p

The predicate used to test elements.

Returns:

the longest prefix of this iterable collection whose elements all satisfy the predicate p.

Inherited from:
IterableOps
Source:
Iterable.scala
def to[C1](factory: Factory[A, C1]): C1
Implicitly added by option2Iterable

Given a collection factory factory, convert this collection to the appropriate representation for the current element type A.

Given a collection factory factory, convert this collection to the appropriate representation for the current element type A. Example uses:

xs.to(List) xs.to(ArrayBuffer) xs.to(BitSet) // for xs: Iterable[Int]

Attributes

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def toArray[B >: A : ClassTag]: Array[B]
Implicitly added by option2Iterable

Convert collection to array.

Convert collection to array.

Implementation note: DO NOT call Array.from from this method.

Attributes

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
final def toBuffer[B >: A]: Buffer[B]
Implicitly added by option2Iterable

Attributes

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
Implicitly added by option2Iterable

Attributes

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def toList: List[A]
Implicitly added by option2Iterable

Attributes

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def toMap[K, V](implicit ev: A <:< (K, V)): Map[K, V]
Implicitly added by option2Iterable

Attributes

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def toSeq: Seq[A]
Implicitly added by option2Iterable

Attributes

Returns:

This collection as a Seq[A]. This is equivalent to to(Seq) but might be faster.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def toSet[B >: A]: Set[B]
Implicitly added by option2Iterable

Attributes

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
Implicitly added by option2Iterable

Attributes

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def transpose[B](implicit asIterable: A => Iterable[B]): CC[CC[B]]
Implicitly added by option2Iterable

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

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.

Attributes

B

the type of the elements of each iterable collection.

asIterable

an implicit conversion which asserts that the element type of this iterable collection is an Iterable.

Returns:

a two-dimensional iterable collection of iterable collections which has as nth row the nth column of this iterable collection.

Throws:

IllegalArgumentException if all collections in this iterable collection are not of the same size.

Inherited from:
IterableOps
Source:
Iterable.scala
def unzip[A1, A2](implicit asPair: A => (A1, A2)): (CC[A1], CC[A2])
Implicitly added by option2Iterable

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

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))

Attributes

A1

the type of the first half of the element pairs

A2

the type of the second half of the element pairs

asPair

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

Returns:

a pair of iterable collections, containing the first, respectively second half of each element pair of this iterable collection.

Inherited from:
IterableOps
Source:
Iterable.scala
def unzip3[A1, A2, A3](implicit asTriple: A => (A1, A2, A3)): (CC[A1], CC[A2], CC[A3])
Implicitly added by option2Iterable

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

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))

Attributes

A1

the type of the first member of the element triples

A2

the type of the second member of the element triples

A3

the type of the third member of the element triples

asTriple

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

Returns:

a triple of iterable collections, containing the first, second, respectively third member of each element triple of this iterable collection.

Inherited from:
IterableOps
Source:
Iterable.scala
def view: View[A]
Implicitly added by option2Iterable

A view over the elements of this collection.

A view over the elements of this collection.

Attributes

Inherited from:
IterableOps
Source:
Iterable.scala
def withFilter(p: A => Boolean): WithFilter[A, CC]
Implicitly added by option2Iterable

Creates a non-strict filter of this iterable collection.

Creates a non-strict filter of this iterable collection.

Note: the difference between c filter p and c withFilter p is that the former creates a new collection, whereas the latter only restricts the domain of subsequent map, flatMap, foreach, and withFilter operations.

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

Attributes

p

the predicate used to test elements.

Returns:

an object of class WithFilter, which supports map, flatMap, foreach, and withFilter operations. All these operations apply to those elements of this iterable collection which satisfy the predicate p.

Inherited from:
IterableOps
Source:
Iterable.scala
def zip[B](that: IterableOnce[B]): CC[(A, B)]
Implicitly added by option2Iterable

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.

Attributes

B

the type of the second half of the returned pairs

that

The iterable providing the second half of each result pair

Returns:

a new iterable collection containing pairs consisting of corresponding elements of this iterable collection and that. The length of the returned collection is the minimum of the lengths of this iterable collection and that.

Inherited from:
IterableOps
Source:
Iterable.scala
def zipAll[A1 >: A, B](that: Iterable[B], thisElem: A1, thatElem: B): CC[(A1, B)]
Implicitly added by option2Iterable

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.

Attributes

that

the iterable providing the second half of each result pair

thatElem

the element to be used to fill up the result if that is shorter than this iterable collection.

thisElem

the element to be used to fill up the result if this iterable collection is shorter than that.

Returns:

a new collection of type That containing pairs consisting of corresponding elements of this iterable collection and that. The length of the returned collection is the maximum of the lengths of this iterable collection and that. If this iterable collection is shorter than that, thisElem values are used to pad the result. If that is shorter than this iterable collection, thatElem values are used to pad the result.

Inherited from:
IterableOps
Source:
Iterable.scala
def zipWithIndex: CC[(A, Int)]
Implicitly added by option2Iterable

Zips this iterable collection with its indices.

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 at 0.

Example:

List("a", "b", "c").zipWithIndex == List(("a", 0), ("b", 1), ("c", 2))

Inherited from:
IterableOps
Source:
Iterable.scala

Deprecated and Inherited methods

def ++:[B >: A](that: IterableOnce[B]): CC[B]
Implicitly added by option2Iterable

Attributes

Deprecated
true
Inherited from:
IterableOps
Source:
Iterable.scala
final def /:[B](z: B)(op: (B, A) => B): B
Implicitly added by option2Iterable

Attributes

Deprecated
true
Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
final def :\[B](z: B)(op: (A, B) => B): B
Implicitly added by option2Iterable

Attributes

Deprecated
true
Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
def aggregate[B](z: => B)(seqop: (B, A) => B, combop: (B, B) => B): B
Implicitly added by option2Iterable

Attributes

Deprecated
true
Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
Implicitly added by option2Iterable

Attributes

Deprecated
true
Inherited from:
IterableOps
Source:
Iterable.scala
final def copyToBuffer[B >: A](dest: Buffer[B]): Unit
Implicitly added by option2Iterable

Attributes

Deprecated
true
Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
Implicitly added by option2Iterable

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 as Stream, the predicate returns true if all elements have been computed. It returns false if the stream is not yet evaluated to the end. Non-empty Iterators usually return false 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 that hasDefiniteSize returns true. However, checking hasDefiniteSize 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:

method knownSize for a more useful alternative

Deprecated

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 though hasDefiniteSize returns false.

Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
final def repr: C
Implicitly added by option2Iterable

Attributes

Deprecated
true
Inherited from:
IterableOps
Source:
Iterable.scala
final def toIterator: Iterator[A]
Implicitly added by option2Iterable

Attributes

Deprecated
true
Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
final def toStream: Stream[A]
Implicitly added by option2Iterable

Attributes

Deprecated
true
Inherited from:
IterableOnceOps
Source:
IterableOnce.scala
final def toTraversable: Iterable[A]
Implicitly added by option2Iterable

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
true
Inherited from:
IterableOps
Source:
Iterable.scala
def view(from: Int, until: Int): View[A]
Implicitly added by option2Iterable

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

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

Attributes

Deprecated
true
Inherited from:
IterableOps
Source:
Iterable.scala