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Class Some.Some
Class Some[A]
represents existing values of type A
.
Supertypes |
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Inherited classlikes
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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.
Inherited from | Option |
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Concrete methods
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def get: A
Returns the option's value.
This is equivalent to:
option match {
case Some(x) => x
case None => throw new Exception
}
Throws |
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Note | The option must be nonempty. |
Inherited methods
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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.
Value parameters |
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Returns | the result of applying |
Example |
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Inherited from | Option |
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Tests whether the option contains a given value as an element.
This is equivalent to:
option match {
case Some(x) => x == elem
case None => false
}
Value parameters |
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Returns |
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Example |
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Inherited from | Option |
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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
}
Value parameters |
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Inherited from | Option |
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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
}
Value parameters |
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Inherited from | Option |
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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
}
Value parameters |
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Inherited from | Option |
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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
}
Value parameters |
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See also | map foreach |
Inherited from | Option |
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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
}
Value parameters |
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See also | flatMap |
Example |
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Inherited from | Option |
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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. 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
Value parameters |
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Inherited from | Option |
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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
}
Value parameters |
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Inherited from | Option |
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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 => ()
}
Value parameters |
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See also | map flatMap |
Inherited from | Option |
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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
.
This is equivalent to:
option match {
case Some(x) => x
case None => default
}
Value parameters |
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Inherited from | Option |
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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
}
Inherited from | Option |
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Returns true if the option is None
, false otherwise.
This is equivalent to:
option match {
case Some(_) => false
case None => true
}
Inherited from | Option |
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Returns a singleton iterator returning the scala.Option's value if it is nonempty, or an empty iterator if the option is empty.
Inherited from | Option |
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Returns | The number of elements in this option, if it can be cheaply computed, -1 otherwise. Cheaply usually means: Not requiring a collection traversal. |
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Definition Classes | Option -> IterableOnce |
Inherited from | Option |
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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
}
Value parameters |
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See also | flatMap foreach |
Note | This is similar to |
Inherited from | Option |
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Returns false if the option is None
, true otherwise.
This is equivalent to:
option match {
case Some(_) => true
case None => false
}
Note | Implemented here to avoid the implicit conversion to Iterable. |
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Inherited from | Option |
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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
}
Value parameters |
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Inherited from | Option |
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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
}
Example |
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Inherited from | Option |
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An iterator over the names of all the elements of this product.
Inherited from | Product |
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An iterator over all the elements of this product.
Returns | in the default implementation, an |
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Inherited from | Product |
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Returns a scala.collection.Stepper for the elements of this collection.
The Stepper enables creating a Java stream to operate on the collection, see scala.jdk.StreamConverters. For collections holding primitive values, the Stepper can be used as an iterator which doesn't box the elements.
The implicit scala.collection.StepperShape parameter defines the resulting Stepper type according to the element type of this collection.
For collections of
Int
,Short
,Byte
orChar
, an scala.collection.IntStepper is returnedFor collections of
Double
orFloat
, a scala.collection.DoubleStepper is returnedFor collections of
Long
a scala.collection.LongStepper is returnedFor any other element type, an scala.collection.AnyStepper is returned
Note that this method is overridden in subclasses and the return type is refined to S with EfficientSplit
, for example scala.collection.IndexedSeqOps.stepper. For Steppers marked with scala.collection.Stepper.EfficientSplit, the converters in scala.jdk.StreamConverters allow creating parallel streams, whereas bare Steppers can be converted only to sequential streams.
Inherited from | IterableOnce |
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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)
}
Value parameters |
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See also | toRight |
Inherited from | Option |
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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
}
Inherited from | Option |
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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)
}
Value parameters |
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See also | toLeft |
Inherited from | Option |
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Converts an Option of a pair into an Option of the first element and an Option of the second element.
This is equivalent to:
option match {
case Some((x, y)) => (Some(x), Some(y))
case _ => (None, None)
}
Type parameters |
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Value parameters |
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Returns | a pair of Options, containing, respectively, the first and second half of the element pair of this Option. |
Inherited from | Option |
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Converts an Option of a triple into three Options, one containing the element from each position of the triple.
This is equivalent to:
option match {
case Some((x, y, z)) => (Some(x), Some(y), Some(z))
case _ => (None, None, None)
}
Type parameters |
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Value parameters |
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Returns | a triple of Options, containing, respectively, the first, second, and third elements from the element triple of this Option. |
Inherited from | Option |
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Necessary to keep scala.Option from being implicitly converted to scala.collection.Iterable in for
comprehensions.
Inherited from | Option |
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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
}
Value parameters |
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Example |
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Inherited from | Option |
© 2002-2022 EPFL, with contributions from Lightbend.
Licensed under the Apache License, Version 2.0.
https://scala-lang.org/api/3.2.0/scala/Some.html