in scala
class Option

sealed abstract class Option [+A]
extends java.lang.Object
with scala.Product
with scala.ScalaObject
This class represents optional values. Instances of Option are either instances of case class Some or it is case object None.
Author:
Martin Odersky
Author:
Matthias Zenger
Version:
1.1, 16/01/2007
Direct Known Subclasses:
None, Some

Constructor Summary
def this

Def Summary
def elements : scala.Iterator[A]
An singleton iterator returning the option's value if it is nonempty or the empty iterator if the option is empty.
def filter (p: (A) => scala.Boolean) : scala.Option[A]
If the option is nonempty and the given predicate p yields false on its value, return None. Otherwise return the option value itself.
def flatMap [B] (f: (A) => scala.Option[B]) : scala.Option[B]
If the option is nonempty, return a function applied to its value. Otherwise return None.
def foreach (f: (A) => scala.Unit) : scala.Unit
Apply the given procedure f to the option's value, if it is nonempty. Do nothing if it is empty.
def get [B >: A] (default: B) : B

abstract def get : A
get the value of this option. @requires that the option is nonEmpty.
def getOrElse [B >: A] (default: => B) : B
If the option is nonempty return its value, otherwise return the result of evaluating a default expression.
def isDefined : scala.Boolean
True if the option is a Some(...) false otherwise.
abstract def isEmpty : scala.Boolean
True if the option is the None value, false otherwise.
def map [B] (f: (A) => B) : scala.Option[B]
If the option is nonempty, return a function applied to its value, wrapped in a Some i.e. Some(f(this.get)). Otherwise return None.
def orElse [B >: A] (alternative: => scala.Option[B]) : scala.Option[B]
If the option is nonempty return it, otherwise return the result of evaluating an alternative expression.
def toList : scala.List[A]
A singleton list containing the option's value if it is nonempty or the empty list if the option is empty.
Def inherited from scala.Product
arity , element, productPrefix
Constructor Detail
def this

Def Detail
def elements : scala.Iterator[A]
An singleton iterator returning the option's value if it is nonempty or the empty iterator if the option is empty.

def filter (p: (A) => scala.Boolean): scala.Option[A]
If the option is nonempty and the given predicate p yields false on its value, return None. Otherwise return the option value itself.
Parameters:
p - the predicate used for testing.

def flatMap [B](f: (A) => scala.Option[B]): scala.Option[B]
If the option is nonempty, return a function applied to its value. Otherwise return None.
Parameters:
f - the function to apply

def foreach (f: (A) => scala.Unit): scala.Unit
Apply the given procedure f to the option's value, if it is nonempty. Do nothing if it is empty.
Parameters:
f - the procedure to apply.

[scala.deprecated]

def get [B >: A](default: B): B
Deprecated:
; use getOrElse instead

abstract def get : A
get the value of this option. @requires that the option is nonEmpty.
Throws:
Predef.NoSuchElementException - if the option is empty.

def getOrElse [B >: A](default: => B): B
If the option is nonempty return its value, otherwise return the result of evaluating a default expression.
Parameters:
default - the default expression.

def isDefined : scala.Boolean
True if the option is a Some(...) false otherwise.

abstract def isEmpty : scala.Boolean
True if the option is the None value, false otherwise.

def map [B](f: (A) => B): scala.Option[B]
If the option is nonempty, return a function applied to its value, wrapped in a Some i.e. Some(f(this.get)). Otherwise return None.
Parameters:
f - the function to apply

def orElse [B >: A](alternative: => scala.Option[B]): scala.Option[B]
If the option is nonempty return it, otherwise return the result of evaluating an alternative expression.
Parameters:
alternative - the alternative expression.

def toList : scala.List[A]
A singleton list containing the option's value if it is nonempty or the empty list if the option is empty.