scala

# None

#### object None extends Option[Nothing] with Product with Serializable

This case object represents non-existent values.

Version

  1.0, 16/07/2003

Linear Supertypes
Option[Nothing], Serializable, java.io.Serializable, Product, Equals, AnyRef, Any
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Inherited

1. None
2. Option
3. Serializable
4. Serializable
5. Product
6. Equals
7. AnyRef
8. Any

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Visibility

1. Public
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### Type Members

1. #### class WithFilter extends AnyRef

   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.

### Value Members

1. #### final def !=(arg0: Any): Boolean

   Definition Classes
     AnyRef → Any

2. #### final def ##(): Int

   Definition Classes
     AnyRef → Any

3. #### final def ==(arg0: Any): Boolean

   Definition Classes
     AnyRef → Any

4. #### final def asInstanceOf[T0]: T0

   Definition Classes
     Any

5. #### def clone(): AnyRef

   Attributes
     protected[java.lang]
   Definition Classes
     AnyRef
   Annotations
     @throws( ... )

6. #### final def collect[B](pf: PartialFunction[Nothing, 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.

   pf

     the partial function.

   returns

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

   Definition Classes
     Option
   Annotations
     @inline()

7. #### final def contains[A1 >: Nothing](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.

   elem

     the element to test.

   returns

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

   Definition Classes
     Option

8. #### final def eq(arg0: AnyRef): Boolean

   Definition Classes
     AnyRef

9. #### def equals(arg0: Any): Boolean

   Definition Classes
     AnyRef → Any

10. #### final def exists(p: (Nothing) ⇒ 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.

    p

      the predicate to test

    Definition Classes
      Option
    Annotations
      @inline()

11. #### final def filter(p: (Nothing) ⇒ Boolean): Option[Nothing]

    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`.

    p

      the predicate used for testing.

    Definition Classes
      Option
    Annotations
      @inline()

12. #### final def filterNot(p: (Nothing) ⇒ Boolean): Option[Nothing]

    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`.

    p

      the predicate used for testing.

    Definition Classes
      Option
    Annotations
      @inline()

13. #### def finalize(): Unit

    Attributes
      protected[java.lang]
    Definition Classes
      AnyRef
    Annotations
      @throws( classOf[java.lang.Throwable] )

14. #### final def flatMap[B](f: (Nothing) ⇒ 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`).

    f

      the function to apply

    Definition Classes
      Option
    Annotations
      @inline()
    See also

      foreach

      map

15. #### def flatten[B](implicit ev: <:<[Nothing, Option[B]]): Option[B]

    Definition Classes
      Option

16. #### final def fold[B](ifEmpty: ⇒ B)(f: (Nothing) ⇒ 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`.

    ifEmpty

      the expression to evaluate if empty.

    f

      the function to apply if nonempty.

    Definition Classes
      Option
    Annotations
      @inline()
    Note

      This is equivalent to `scala.Option map f getOrElse ifEmpty`.

17. #### final def forall(p: (Nothing) ⇒ 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.

    p

      the predicate to test

    Definition Classes
      Option
    Annotations
      @inline()

18. #### final def foreach[U](f: (Nothing) ⇒ 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.

    f

      the procedure to apply.

    Definition Classes
      Option
    Annotations
      @inline()
    See also

      flatMap

      map

19. #### def get: Nothing

    Returns the option's value.

    Returns the option's value.

    Definition Classes
      None → Option
    Exceptions thrown
      Predef.NoSuchElementException

      if the option is empty.

    Note

      The option must be nonEmpty.

20. #### final def getClass(): Class[_]

    Definition Classes
      AnyRef → Any

21. #### final def getOrElse[B >: Nothing](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`.

    default

      the default expression.

    Definition Classes
      Option
    Annotations
      @inline()

22. #### 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.

    Definition Classes
      Option

23. #### def isEmpty: Boolean

    Returns true if the option is `None`, false otherwise.

    Returns true if the option is `None`, false otherwise.

    Definition Classes
      None → Option

24. #### final def isInstanceOf[T0]: Boolean

    Definition Classes
      Any

25. #### def iterator: Iterator[Nothing]

    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.

    Definition Classes
      Option

26. #### final def map[B](f: (Nothing) ⇒ 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`.

    f

      the function to apply

    Definition Classes
      Option
    Annotations
      @inline()
    Note

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

    See also

      foreach

      flatMap

27. #### final def ne(arg0: AnyRef): Boolean

    Definition Classes
      AnyRef

28. #### final def nonEmpty: Boolean

    Returns false if the option is `None`, true otherwise.

    Returns false if the option is `None`, true otherwise.

    Definition Classes
      Option
    Note

      Implemented here to avoid the implicit conversion to Iterable.

29. #### final def notify(): Unit

    Definition Classes
      AnyRef

30. #### final def notifyAll(): Unit

    Definition Classes
      AnyRef

31. #### final def orElse[B >: Nothing](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`.

    alternative

      the alternative expression.

    Definition Classes
      Option
    Annotations
      @inline()

32. #### final def orNull[A1 >: Nothing](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.

    Definition Classes
      Option
    Annotations
      @inline()
    Example:

    1.     val initalText: Option[String] = getInitialText
           val textField = new JComponent(initalText.orNull,20)

33. #### final def synchronized[T0](arg0: ⇒ T0): T0

    Definition Classes
      AnyRef

34. #### final def toLeft[X](right: ⇒ X): Product with Serializable with util.Either[Nothing, 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.

    right

      the expression to evaluate and return if this is empty

    Definition Classes
      Option
    Annotations
      @inline()
    See also

      toRight

35. #### def toList: List[Nothing]

    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.

    Definition Classes
      Option

36. #### final def toRight[X](left: ⇒ X): Product with Serializable with util.Either[X, Nothing]

    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.

    left

      the expression to evaluate and return if this is empty

    Definition Classes
      Option
    Annotations
      @inline()
    See also

      toLeft

37. #### final def wait(): Unit

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

38. #### final def wait(arg0: Long, arg1: Int): Unit

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

39. #### final def wait(arg0: Long): Unit

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

40. #### final def withFilter(p: (Nothing) ⇒ 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.

    Definition Classes
      Option
    Annotations
      @inline()

### Inherited from Option[Nothing]

### Inherited from Serializable

### Inherited from java.io.Serializable

### Inherited from Product

### Inherited from Equals

### Inherited from AnyRef

### Inherited from Any

### Ungrouped