final case class Some[+A](value: A) extends Option[A] with Product with Serializable
Class Some[A]
represents existing values of type
A
.
- Annotations
- @SerialVersionUID()
- Source
- Option.scala
- Since
1.0
- Alphabetic
- By Inheritance
- Some
- Option
- Serializable
- Serializable
- Product
- Equals
- AnyRef
- Any
- by option2Iterable
- by any2stringadd
- by StringFormat
- by Ensuring
- by ArrowAssoc
- Hide All
- Show All
- Public
- All
Instance Constructors
- new Some(value: A)
Type Members
-
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.
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.
- Definition Classes
- Option
Value Members
-
final
def
!=(arg0: Any): Boolean
Test two objects for inequality.
Test two objects for inequality.
- returns
true
if !(this == that), false otherwise.
- Definition Classes
- AnyRef → Any
-
final
def
##(): Int
Equivalent to
x.hashCode
except for boxed numeric types andnull
.Equivalent to
x.hashCode
except for boxed numeric types andnull
. For numerics, it returns a hash value which is consistent with value equality: if two value type instances compare as true, then ## will produce the same hash value for each of them. Fornull
returns a hashcode wherenull.hashCode
throws aNullPointerException
.- returns
a hash value consistent with ==
- Definition Classes
- AnyRef → Any
-
def
+(other: String): String
- Implicit
- This member is added by an implicit conversion from Some[A] to any2stringadd[Some[A]] performed by method any2stringadd in scala.Predef.
- Definition Classes
- any2stringadd
-
def
++[B >: A, That](that: GenTraversableOnce[B])(implicit bf: CanBuildFrom[collection.Iterable[A], B, That]): That
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.
- B
the element type of the returned collection.
- That
the class of the returned collection. Where possible,
That
is the same class as the current collection classRepr
, but this depends on the element typeB
being admissible for that class, which means that an implicit instance of typeCanBuildFrom[Repr, B, That]
is found.- that
the traversable to append.
- bf
an implicit value of class
CanBuildFrom
which determines the result classThat
from the current representation typeRepr
and the new element typeB
.- returns
a new collection of type
That
which contains all elements of this iterable collection followed by all elements ofthat
.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableLike → GenTraversableLike
-
def
++:[B >: A, That](that: collection.Traversable[B])(implicit bf: CanBuildFrom[collection.Iterable[A], B, That]): That
As with
++
, returns a new collection containing the elements from the left operand followed by the elements from the right operand.As with
++
, returns a new collection containing the elements from the left operand followed by the elements from the right operand.It differs from
++
in that the right operand determines the type of the resulting collection rather than the left one. Mnemonic: the COLon is on the side of the new COLlection type.Example:
scala> val x = List(1) x: List[Int] = List(1) scala> val y = LinkedList(2) y: scala.collection.mutable.LinkedList[Int] = LinkedList(2) scala> val z = x ++: y z: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2)
This overload exists because: for the implementation of
++:
we should reuse that of++
because many collections override it with more efficient versions.Since
TraversableOnce
has no++
method, we have to implement that directly, butTraversable
and down can use the overload.- B
the element type of the returned collection.
- That
the class of the returned collection. Where possible,
That
is the same class as the current collection classRepr
, but this depends on the element typeB
being admissible for that class, which means that an implicit instance of typeCanBuildFrom[Repr, B, That]
is found.- that
the traversable to append.
- bf
an implicit value of class
CanBuildFrom
which determines the result classThat
from the current representation typeRepr
and the new element typeB
.- returns
a new collection of type
That
which contains all elements of this iterable collection followed by all elements ofthat
.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableLike
-
def
++:[B](that: collection.TraversableOnce[B]): Option[B]
[use case] As with
++
, returns a new collection containing the elements from the left operand followed by the elements from the right operand.[use case]As with
++
, returns a new collection containing the elements from the left operand followed by the elements from the right operand.It differs from
++
in that the right operand determines the type of the resulting collection rather than the left one. Mnemonic: the COLon is on the side of the new COLlection type.Example:
scala> val x = List(1) x: List[Int] = List(1) scala> val y = LinkedList(2) y: scala.collection.mutable.LinkedList[Int] = LinkedList(2) scala> val z = x ++: y z: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2)
- B
the element type of the returned collection.
- that
the traversable to append.
- returns
a new option which contains all elements of this option followed by all elements of
that
.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableLike
Full Signaturedef ++:[B >: A, That](that: collection.TraversableOnce[B])(implicit bf: CanBuildFrom[collection.Iterable[A], B, That]): That
-
def
->[B](y: B): (Some[A], B)
- Implicit
- This member is added by an implicit conversion from Some[A] to ArrowAssoc[Some[A]] performed by method ArrowAssoc in scala.Predef.
- Definition Classes
- ArrowAssoc
- Annotations
- @inline()
-
final
def
==(arg0: Any): Boolean
The expression
x == that
is equivalent toif (x eq null) that eq null else x.equals(that)
.The expression
x == that
is equivalent toif (x eq null) that eq null else x.equals(that)
.- returns
true
if the receiver object is equivalent to the argument;false
otherwise.
- Definition Classes
- AnyRef → Any
-
def
addString(b: StringBuilder): StringBuilder
Appends all elements of this iterable collection to a string builder.
Appends all elements of this iterable collection to a string builder. The written text consists of the string representations (w.r.t. the method
toString
) of all elements of this iterable 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
- b
the string builder to which elements are appended.
- returns
the string builder
b
to which elements were appended.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce
-
def
addString(b: StringBuilder, sep: String): StringBuilder
Appends all elements of this iterable collection to a string builder using a separator string.
Appends all elements of this iterable 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 iterable collection, separated by the stringsep
.Example:
scala> val a = List(1,2,3,4) a: List[Int] = List(1, 2, 3, 4) scala> val b = new StringBuilder() b: StringBuilder = scala> a.addString(b, ", ") res0: StringBuilder = 1, 2, 3, 4
- b
the string builder to which elements are appended.
- sep
the separator string.
- returns
the string builder
b
to which elements were appended.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce
-
def
addString(b: StringBuilder, start: String, sep: String, end: String): StringBuilder
Appends all elements of this iterable collection to a string builder using start, end, and separator strings.
Appends all elements of this iterable collection to a string builder using start, end, and separator strings. The written text begins with the string
start
and ends with the stringend
. Inside, the string representations (w.r.t. the methodtoString
) of all elements of this iterable collection are separated by the stringsep
.Example:
scala> val a = List(1,2,3,4) a: List[Int] = List(1, 2, 3, 4) scala> val b = new StringBuilder() b: StringBuilder = scala> a.addString(b , "List(" , ", " , ")") res5: StringBuilder = List(1, 2, 3, 4)
- b
the string builder to which elements are appended.
- start
the starting string.
- sep
the separator string.
- end
the ending string.
- returns
the string builder
b
to which elements were appended.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce
-
def
aggregate[B](z: ⇒ B)(seqop: (B, A) ⇒ B, combop: (B, B) ⇒ B): B
Aggregates the results of applying an operator to subsequent elements.
Aggregates the results of applying an operator to subsequent elements.
This is a more general form of
fold
andreduce
. It is similar tofoldLeft
in that it doesn't require the result to be a supertype of the element type. In addition, it allows parallel collections to be processed in chunks, and then combines the intermediate results.aggregate
splits the iterable collection into partitions and processes each partition by sequentially applyingseqop
, starting withz
(likefoldLeft
). Those intermediate results are then combined by usingcombop
(likefold
). The implementation of this operation may operate on an arbitrary number of collection partitions (even 1), socombop
may be invoked an arbitrary number of times (even 0).As an example, consider summing up the integer values of a list of chars. The initial value for the sum is 0. First,
seqop
transforms each input character to an Int and adds it to the sum (of the partition). Then,combop
just needs to sum up the intermediate results of the partitions:List('a', 'b', 'c').aggregate(0)({ (sum, ch) => sum + ch.toInt }, { (p1, p2) => p1 + p2 })
- B
the type of accumulated results
- z
the initial value for the accumulated result of the partition - this will typically be the neutral element for the
seqop
operator (e.g.Nil
for list concatenation or0
for summation) and may be evaluated more than once- seqop
an operator used to accumulate results within a partition
- combop
an associative operator used to combine results from different partitions
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
-
final
def
asInstanceOf[T0]: T0
Cast the receiver object to be of type
T0
.Cast the receiver object to be of type
T0
.Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression
1.asInstanceOf[String]
will throw aClassCastException
at runtime, while the expressionList(1).asInstanceOf[List[String]]
will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested type.- returns
the receiver object.
- Definition Classes
- Any
- Exceptions thrown
ClassCastException
if the receiver object is not an instance of the erasure of typeT0
.
-
def
canEqual(that: Any): Boolean
Method called from equality methods, so that user-defined subclasses can refuse to be equal to other collections of the same kind.
Method called from equality methods, so that user-defined subclasses can refuse to be equal to other collections of the same kind.
- that
The object with which this iterable collection should be compared
- returns
true
, if this iterable collection can possibly equalthat
,false
otherwise. The test takes into consideration only the run-time types of objects but ignores their elements.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- IterableLike → Equals
-
def
clone(): AnyRef
Create a copy of the receiver object.
-
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 andpf
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 andpf
is defined for that value. ReturnsNone
otherwise.- pf
the partial function.
- returns
the result of applying
pf
to this scala.Option's value (if possible), orNone
.
- Definition Classes
- Option
- Annotations
- @inline()
// 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}
Example: -
def
collectFirst[B](pf: PartialFunction[A, B]): Option[B]
Finds the first element of the iterable collection for which the given partial function is defined, and applies the partial function to it.
Finds the first element of the iterable 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.
- 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.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce
Seq("a", 1, 5L).collectFirst({ case x: Int => x*10 }) = Some(10)
Example: -
def
companion: GenericCompanion[collection.Iterable]
The factory companion object that builds instances of class Iterable.
The factory companion object that builds instances of class Iterable. (or its
Iterable
superclass where class Iterable is not aSeq
.)- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- Iterable → GenIterable → Traversable → GenTraversable → GenericTraversableTemplate
-
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 }
- elem
the element to test.
- returns
true
if the option has an element that is equal (as determined by==
) toelem
,false
otherwise.
- Definition Classes
- Option
// 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"
Example: -
def
copyToArray(xs: Array[A], start: Int, len: Int): Unit
[use case] Copies the elements of this option to an array.
[use case]Copies the elements of this option to an array. Fills the given array
xs
with at mostlen
elements of this option, starting at positionstart
. Copying will stop once either the end of the current option is reached, or the end of the target array is reached, orlen
elements have been copied.- xs
the array to fill.
- start
the starting index.
- len
the maximal number of elements to copy.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- IterableLike → TraversableLike → TraversableOnce → GenTraversableOnce
-
def
copyToArray(xs: Array[A]): Unit
[use case] Copies the elements of this option to an array.
[use case]Copies the elements of this option to an array. Fills the given array
xs
with values of this option. Copying will stop once either the end of the current option is reached, or the end of the target array is reached.- xs
the array to fill.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
-
def
copyToArray(xs: Array[A], start: Int): Unit
[use case] Copies the elements of this option to an array.
[use case]Copies the elements of this option to an array. Fills the given array
xs
with values of this option, beginning at indexstart
. Copying will stop once either the end of the current option is reached, or the end of the target array is reached.- xs
the array to fill.
- start
the starting index.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
-
def
copyToBuffer[B >: A](dest: Buffer[B]): Unit
Copies all elements of this iterable collection to a buffer.
Copies all elements of this iterable collection to a buffer.
Note: will not terminate for infinite-sized collections.
- dest
The buffer to which elements are copied.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce
-
def
count(p: (A) ⇒ Boolean): Int
Counts the number of elements in the iterable collection which satisfy a predicate.
Counts the number of elements in the iterable collection which satisfy a predicate.
- p
the predicate used to test elements.
- returns
the number of elements satisfying the predicate
p
.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
-
def
drop(n: Int): collection.Iterable[A]
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.
- 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 thann
elements. Ifn
is negative, don't drop any elements.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- IterableLike → TraversableLike → GenTraversableLike
-
def
dropRight(n: Int): collection.Iterable[A]
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.
- n
The number of elements to take
- 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 thann
elements.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- IterableLike
-
def
dropWhile(p: (A) ⇒ Boolean): collection.Iterable[A]
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.
- returns
the longest suffix of this iterable collection whose first element does not satisfy the predicate
p
.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableLike → GenTraversableLike
-
def
ensuring(cond: (Some[A]) ⇒ Boolean, msg: ⇒ Any): Some[A]
- Implicit
- This member is added by an implicit conversion from Some[A] to Ensuring[Some[A]] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
-
def
ensuring(cond: (Some[A]) ⇒ Boolean): Some[A]
- Implicit
- This member is added by an implicit conversion from Some[A] to Ensuring[Some[A]] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
-
def
ensuring(cond: Boolean, msg: ⇒ Any): Some[A]
- Implicit
- This member is added by an implicit conversion from Some[A] to Ensuring[Some[A]] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
-
def
ensuring(cond: Boolean): Some[A]
- Implicit
- This member is added by an implicit conversion from Some[A] to Ensuring[Some[A]] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
-
final
def
eq(arg0: AnyRef): Boolean
Tests whether the argument (
that
) is a reference to the receiver object (this
).Tests whether the argument (
that
) is a reference to the receiver object (this
).The
eq
method implements an equivalence relation on non-null instances ofAnyRef
, and has three additional properties:- It is consistent: for any non-null instances
x
andy
of typeAnyRef
, multiple invocations ofx.eq(y)
consistently returnstrue
or consistently returnsfalse
. - For any non-null instance
x
of typeAnyRef
,x.eq(null)
andnull.eq(x)
returnsfalse
. null.eq(null)
returnstrue
.
When overriding the
equals
orhashCode
methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (o1 eq o2
), they should be equal to each other (o1 == o2
) and they should hash to the same value (o1.hashCode == o2.hashCode
).- returns
true
if the argument is a reference to the receiver object;false
otherwise.
- Definition Classes
- AnyRef
- It is consistent: for any non-null instances
-
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 }
- p
the predicate to test
-
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, returnNone
.This is equivalent to:
option match { case Some(x) if p(x) => Some(x) case _ => None }
- p
the predicate used for testing.
-
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, returnNone
.This is equivalent to:
option match { case Some(x) if !p(x) => Some(x) case _ => None }
- p
the predicate used for testing.
-
def
finalize(): Unit
Called by the garbage collector on the receiver object when there are no more references to the object.
Called by the garbage collector on the receiver object when there are no more references to the object.
The details of when and if the
finalize
method is invoked, as well as the interaction betweenfinalize
and non-local returns and exceptions, are all platform dependent.- Attributes
- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws( classOf[java.lang.Throwable] )
- Note
not specified by SLS as a member of AnyRef
-
def
find(p: (A) ⇒ Boolean): Option[A]
Finds the first element of the iterable collection satisfying a predicate, if any.
Finds the first element of the iterable 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.
- p
the predicate used to test elements.
- returns
an option value containing the first element in the iterable collection that satisfies
p
, orNone
if none exists.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- IterableLike → TraversableLike → TraversableOnce → GenTraversableOnce
-
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. ReturnsNone
if this scala.Option is empty. Slightly different frommap
in thatf
is expected to return an scala.Option (which could beNone
).This is equivalent to:
option match { case Some(x) => f(x) case None => None }
- f
the function to apply
-
def
flatten[B](implicit ev: <:<[A, Option[B]]): Option[B]
- Definition Classes
- Option
-
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 expressionifEmpty
.This is equivalent to:
option match { case Some(x) => f(x) case None => ifEmpty }
This is also equivalent to:
option map f getOrElse ifEmpty
- ifEmpty
the expression to evaluate if empty.
- f
the function to apply if nonempty.
-
def
foldLeft[B](z: B)(op: (B, A) ⇒ B): B
Applies a binary operator to a start value and all elements of this iterable collection, going left to right.
Applies a binary operator to a start value and all elements of this iterable 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.
- B
the result type of the binary operator.
- z
the start value.
- op
the binary operator.
- returns
the result of inserting
op
between consecutive elements of this iterable collection, going left to right with the start valuez
on the left:op(...op(z, x_1), x_2, ..., x_n)
where
x1, ..., xn
are the elements of this iterable collection. Returnsz
if this iterable collection is empty.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
-
def
foldRight[B](z: B)(op: (A, B) ⇒ B): B
Applies a binary operator to all elements of this iterable collection and a start value, going right to left.
Applies a binary operator to all elements of this iterable 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.
- B
the result type of the binary operator.
- z
the start value.
- op
the binary operator.
- returns
the result of inserting
op
between consecutive elements of this iterable collection, going right to left with the start valuez
on the right:op(x_1, op(x_2, ... op(x_n, z)...))
where
x1, ..., xn
are the elements of this iterable collection. Returnsz
if this iterable collection is empty.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- IterableLike → TraversableOnce → GenTraversableOnce
-
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 }
- p
the predicate to test
-
final
def
foreach[U](f: (A) ⇒ U): Unit
Apply the given procedure
f
to the option's value, if it is nonempty. -
def
formatted(fmtstr: String): String
Returns string formatted according to given
format
string.Returns string formatted according to given
format
string. Format strings are as forString.format
(@see java.lang.String.format).- Implicit
- This member is added by an implicit conversion from Some[A] to StringFormat[Some[A]] performed by method StringFormat in scala.Predef.
- Definition Classes
- StringFormat
- Annotations
- @inline()
-
def
genericBuilder[B]: Builder[B, collection.Iterable[B]]
The generic builder that builds instances of Iterable at arbitrary element types.
The generic builder that builds instances of Iterable at arbitrary element types.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- GenericTraversableTemplate
-
def
get: A
Returns the option's value.
-
final
def
getClass(): Class[_]
Returns the runtime class representation of the object.
-
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
. -
def
groupBy[K](f: (A) ⇒ K): Map[K, collection.Iterable[A]]
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: this method is not re-implemented by views. This means when applied to a view it will always force the view and return a new iterable collection.
- 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 elementsx
for whichf(x)
equalsk
.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableLike → GenTraversableLike
-
def
grouped(size: Int): collection.Iterator[collection.Iterable[A]]
Partitions elements in fixed size iterable collections.
Partitions elements in fixed size iterable collections.
- size
the number of elements per group
- returns
An iterator producing iterable collections of size
size
, except the last will be less than sizesize
if the elements don't divide evenly.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- IterableLike
- See also
scala.collection.Iterator, method
grouped
-
def
hasDefiniteSize: Boolean
Tests whether this iterable collection is known to have a finite size.
Tests whether this iterable 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 returnstrue
if all elements have been computed. It returnsfalse
if the stream is not yet evaluated to the end. Non-empty Iterators usually returnfalse
even if they were created from a collection with a known finite size.Note: many collection methods will not work on collections of infinite sizes. The typical failure mode is an infinite loop. These methods always attempt a traversal without checking first that
hasDefiniteSize
returnstrue
. However, checkinghasDefiniteSize
can provide an assurance that size is well-defined and non-termination is not a concern.- returns
true
if this collection is known to have finite size,false
otherwise.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableLike → TraversableOnce → GenTraversableOnce
-
def
head: A
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.
- returns
the first element of this iterable collection.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- IterableLike → TraversableLike → GenTraversableLike
- Exceptions thrown
NoSuchElementException
if the iterable collection is empty.
-
def
headOption: Option[A]
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.
- returns
the first element of this iterable collection if it is nonempty,
None
if it is empty.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableLike → GenTraversableLike
-
def
init: collection.Iterable[A]
Selects all elements except the last.
Selects all elements except the last.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- returns
a iterable collection consisting of all elements of this iterable collection except the last one.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableLike → GenTraversableLike
- Exceptions thrown
UnsupportedOperationException
if the iterable collection is empty.
-
def
inits: collection.Iterator[collection.Iterable[A]]
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
.- returns
an iterator over all the inits of this iterable collection
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableLike
List(1,2,3).inits = Iterator(List(1,2,3), List(1,2), List(1), Nil)
Example: -
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 }
- Definition Classes
- Option
-
def
isEmpty: Boolean
Returns true if the option is
None
, false otherwise. -
final
def
isInstanceOf[T0]: Boolean
Test whether the dynamic type of the receiver object is
T0
.Test whether the dynamic type of the receiver object is
T0
.Note that the result of the test is modulo Scala's erasure semantics. Therefore the expression
1.isInstanceOf[String]
will returnfalse
, while the expressionList(1).isInstanceOf[List[String]]
will returntrue
. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the specified type.- returns
true
if the receiver object is an instance of erasure of typeT0
;false
otherwise.
- Definition Classes
- Any
-
final
def
isTraversableAgain: Boolean
Tests whether this iterable collection can be repeatedly traversed.
Tests whether this iterable collection can be repeatedly traversed.
- returns
true
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableLike → GenTraversableLike → GenTraversableOnce
-
def
iterator: Iterator[A]
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
-
def
last: A
Selects the last element.
Selects the last element.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- returns
The last element of this iterable collection.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableLike → GenTraversableLike
- Exceptions thrown
NoSuchElementException
If the iterable collection is empty.
-
def
lastOption: Option[A]
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.
- returns
the last element of this iterable collection$ if it is nonempty,
None
if it is empty.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableLike → GenTraversableLike
-
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 returnNone
.This is equivalent to:
option match { case Some(x) => Some(f(x)) case None => 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
flatMap
foreach
-
def
max: A
[use case] Finds the largest element.
[use case]Finds the largest element.
- returns
the largest element of this option.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
- Exceptions thrown
UnsupportedOperationException
if this option is empty.
Full Signaturedef max[B >: A](implicit cmp: Ordering[B]): A
-
def
maxBy[B](f: (A) ⇒ B): A
[use case] Finds the first element which yields the largest value measured by function f.
[use case]Finds the first element which yields the largest value measured by function f.
- B
The result type of the function f.
- f
The measuring function.
- returns
the first element of this option with the largest value measured by function f.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
- Exceptions thrown
UnsupportedOperationException
if this option is empty.
Full Signaturedef maxBy[B](f: (A) ⇒ B)(implicit cmp: Ordering[B]): A
-
def
min: A
[use case] Finds the smallest element.
[use case]Finds the smallest element.
- returns
the smallest element of this option
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
- Exceptions thrown
UnsupportedOperationException
if this option is empty.
Full Signaturedef min[B >: A](implicit cmp: Ordering[B]): A
-
def
minBy[B](f: (A) ⇒ B): A
[use case] Finds the first element which yields the smallest value measured by function f.
[use case]Finds the first element which yields the smallest value measured by function f.
- B
The result type of the function f.
- f
The measuring function.
- returns
the first element of this option with the smallest value measured by function f.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
- Exceptions thrown
UnsupportedOperationException
if this option is empty.
Full Signaturedef minBy[B](f: (A) ⇒ B)(implicit cmp: Ordering[B]): A
-
def
mkString: String
Displays all elements of this iterable collection in a string.
Displays all elements of this iterable collection in a string.
- returns
a string representation of this iterable collection. In the resulting string the string representations (w.r.t. the method
toString
) of all elements of this iterable collection follow each other without any separator string.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
-
def
mkString(sep: String): String
Displays all elements of this iterable collection in a string using a separator string.
Displays all elements of this iterable collection in a string using a separator string.
- sep
the separator string.
- returns
a string representation of this iterable collection. In the resulting string the string representations (w.r.t. the method
toString
) of all elements of this iterable collection are separated by the stringsep
.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
List(1, 2, 3).mkString("|") = "1|2|3"
Example: -
def
mkString(start: String, sep: String, end: String): String
Displays all elements of this iterable collection in a string using start, end, and separator strings.
Displays all elements of this iterable collection in a string using start, end, and separator strings.
- start
the starting string.
- sep
the separator string.
- end
the ending string.
- returns
a string representation of this iterable collection. The resulting string begins with the string
start
and ends with the stringend
. Inside, the string representations (w.r.t. the methodtoString
) of all elements of this iterable collection are separated by the stringsep
.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"
Example: -
final
def
ne(arg0: AnyRef): Boolean
Equivalent to
!(this eq that)
.Equivalent to
!(this eq that)
.- returns
true
if the argument is not a reference to the receiver object;false
otherwise.
- Definition Classes
- AnyRef
-
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 }
- Definition Classes
- Option
- Note
Implemented here to avoid the implicit conversion to Iterable.
-
final
def
notify(): Unit
Wakes up a single thread that is waiting on the receiver object's monitor.
Wakes up a single thread that is waiting on the receiver object's monitor.
- Definition Classes
- AnyRef
- Annotations
- @native()
- Note
not specified by SLS as a member of AnyRef
-
final
def
notifyAll(): Unit
Wakes up all threads that are waiting on the receiver object's monitor.
Wakes up all threads that are waiting on the receiver object's monitor.
- Definition Classes
- AnyRef
- Annotations
- @native()
- Note
not specified by SLS as a member of AnyRef
-
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 }
- alternative
the alternative expression.
-
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 }
-
def
par: ParIterable[A]
Returns a parallel implementation of this collection.
Returns a parallel implementation of this collection.
For most collection types, this method creates a new parallel collection by copying all the elements. For these collection,
par
takes linear time. Mutable collections in this category do not produce a mutable parallel collection that has the same underlying dataset, so changes in one collection will not be reflected in the other one.Specific collections (e.g.
ParArray
ormutable.ParHashMap
) override this default behaviour by creating a parallel collection which shares the same underlying dataset. For these collections,par
takes constant or sublinear time.All parallel collections return a reference to themselves.
- returns
a parallel implementation of this collection
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- Parallelizable
-
def
partition(p: (A) ⇒ Boolean): (collection.Iterable[A], collection.Iterable[A])
Partitions this iterable collection in two iterable collections according to a predicate.
Partitions this iterable collection in two iterable collections according to a predicate.
- p
the predicate on which to partition.
- returns
a pair of iterable collections: the first iterable collection consists of all elements that satisfy the predicate
p
and the second iterable collection consists of all elements that don't. The relative order of the elements in the resulting iterable collections is the same as in the original iterable collection.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableLike → GenTraversableLike
-
def
product: A
[use case] Multiplies up the elements of this collection.
[use case]Multiplies up the elements of this collection.
- returns
the product of all elements in this option of numbers of type
Int
. Instead ofInt
, any other typeT
with an implicitNumeric[T]
implementation can be used as element type of the option and as result type ofproduct
. Examples of such types are:Long
,Float
,Double
,BigInt
.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
Full Signaturedef product[B >: A](implicit num: Numeric[B]): B
-
def
reduce[A1 >: A](op: (A1, A1) ⇒ A1): A1
Reduces the elements of this iterable collection using the specified associative binary operator.
Reduces the elements of this iterable collection using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
- A1
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 iterable collection is nonempty.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
- Exceptions thrown
UnsupportedOperationException
if this iterable collection is empty.
-
def
reduceLeft[B >: A](op: (B, A) ⇒ B): B
Applies a binary operator to all elements of this iterable collection, going left to right.
Applies a binary operator to all elements of this iterable 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.
- B
the result type of the binary operator.
- op
the binary operator.
- returns
the result of inserting
op
between consecutive elements of this iterable collection, going left to right:op( op( ... op(x_1, x_2) ..., x_{n-1}), x_n)
where
x1, ..., xn
are the elements of this iterable collection.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce
- Exceptions thrown
UnsupportedOperationException
if this iterable collection is empty.
-
def
reduceLeftOption[B >: A](op: (B, A) ⇒ B): Option[B]
Optionally applies a binary operator to all elements of this iterable collection, going left to right.
Optionally applies a binary operator to all elements of this iterable 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.
- B
the result type of the binary operator.
- op
the binary operator.
- returns
an option value containing the result of
reduceLeft(op)
if this iterable collection is nonempty,None
otherwise.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
-
def
reduceOption[A1 >: A](op: (A1, A1) ⇒ A1): Option[A1]
Reduces the elements of this iterable collection, if any, using the specified associative binary operator.
Reduces the elements of this iterable collection, if any, using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
- A1
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, andNone
otherwise.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
-
def
reduceRight[B >: A](op: (A, B) ⇒ B): B
Applies a binary operator to all elements of this iterable collection, going right to left.
Applies a binary operator to all elements of this iterable 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.
- B
the result type of the binary operator.
- op
the binary operator.
- returns
the result of inserting
op
between consecutive elements of this iterable collection, going right to left:op(x_1, op(x_2, ..., op(x_{n-1}, x_n)...))
where
x1, ..., xn
are the elements of this iterable collection.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- IterableLike → TraversableOnce → GenTraversableOnce
- Exceptions thrown
UnsupportedOperationException
if this iterable collection is empty.
-
def
reduceRightOption[B >: A](op: (A, B) ⇒ B): Option[B]
Optionally applies a binary operator to all elements of this iterable collection, going right to left.
Optionally applies a binary operator to all elements of this iterable 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.
- B
the result type of the binary operator.
- op
the binary operator.
- returns
an option value containing the result of
reduceRight(op)
if this iterable collection is nonempty,None
otherwise.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
-
def
repr: collection.Iterable[A]
The collection of type iterable collection underlying this
TraversableLike
object.The collection of type iterable collection underlying this
TraversableLike
object. By default this is implemented as theTraversableLike
object itself, but this can be overridden.- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableLike → GenTraversableLike
-
def
sameElements(that: GenIterable[A]): Boolean
[use case] Checks if the other iterable collection contains the same elements in the same order as this option.
[use case]Checks if the other iterable collection contains the same elements in the same order as this option.
- that
the collection to compare with.
- returns
true
, if both collections contain the same elements in the same order,false
otherwise.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- IterableLike → GenIterableLike
Full Signaturedef sameElements[B >: A](that: GenIterable[B]): Boolean
-
def
scan[B >: A, That](z: B)(op: (B, B) ⇒ B)(implicit cbf: CanBuildFrom[collection.Iterable[A], B, That]): That
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.- B
element type of the resulting collection
- That
type of the resulting collection
- z
neutral element for the operator
op
- op
the associative operator for the scan
- cbf
combiner factory which provides a combiner
- returns
a new iterable collection containing the prefix scan of the elements in this iterable collection
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableLike → GenTraversableLike
-
def
scanLeft[B, That](z: B)(op: (B, A) ⇒ B)(implicit bf: CanBuildFrom[collection.Iterable[A], B, That]): That
Produces a collection containing cumulative results of applying the operator going left to right.
Produces a collection containing cumulative results of applying the operator 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.
- B
the type of the elements in the resulting collection
- That
the actual type of the resulting collection
- z
the initial value
- op
the binary operator applied to the intermediate result and the element
- bf
an implicit value of class
CanBuildFrom
which determines the result classThat
from the current representation typeRepr
and the new element typeB
.- returns
collection with intermediate results
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableLike → GenTraversableLike
-
def
scanRight[B, That](z: B)(op: (A, B) ⇒ B)(implicit bf: CanBuildFrom[collection.Iterable[A], B, That]): That
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.
Example:
List(1, 2, 3, 4).scanRight(0)(_ + _) == List(10, 9, 7, 4, 0)
- B
the type of the elements in the resulting collection
- That
the actual type of the resulting collection
- z
the initial value
- op
the binary operator applied to the intermediate result and the element
- bf
an implicit value of class
CanBuildFrom
which determines the result classThat
from the current representation typeRepr
and the new element typeB
.- returns
collection with intermediate results
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableLike → GenTraversableLike
- Annotations
- @migration
- Migration
(Changed in version 2.9.0) The behavior of
scanRight
has changed. The previous behavior can be reproduced with scanRight.reverse.
-
def
seq: collection.Iterable[A]
A version of this collection with all of the operations implemented sequentially (i.e., in a single-threaded manner).
A version of this collection with all of the operations implemented sequentially (i.e., in a single-threaded manner).
This method returns a reference to this collection. In parallel collections, it is redefined to return a sequential implementation of this collection. In both cases, it has O(1) complexity.
- returns
a sequential view of the collection.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- Iterable → GenIterable → Traversable → GenTraversable → Parallelizable → TraversableOnce → GenTraversableOnce
-
def
size: Int
The size of this iterable collection.
The size of this iterable collection.
Note: will not terminate for infinite-sized collections.
- returns
the number of elements in this iterable collection.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
-
def
slice(from: Int, until: Int): collection.Iterable[A]
Selects an interval of elements.
Selects an interval of elements. The returned 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.
- returns
a iterable collection containing the elements greater than or equal to index
from
extending up to (but not including) indexuntil
of this iterable collection.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- IterableLike → TraversableLike → GenTraversableLike
-
def
sliding(size: Int, step: Int): collection.Iterator[collection.Iterable[A]]
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.)
- 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 truncated if there are fewer thansize
elements remaining to be grouped.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- IterableLike
- See also
scala.collection.Iterator, method
sliding
-
def
sliding(size: Int): collection.Iterator[collection.Iterable[A]]
Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in
grouped
.) The "sliding window" step is set to one.Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in
grouped
.) The "sliding window" step is set to one.- size
the number of elements per group
- returns
An iterator producing iterable collections of size
size
, except the last element (which may be the only element) will be truncated if there are fewer thansize
elements remaining to be grouped.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- IterableLike
- See also
scala.collection.Iterator, method
sliding
-
def
span(p: (A) ⇒ Boolean): (collection.Iterable[A], collection.Iterable[A])
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 predicatep
does not cause any side-effects.Note: might return different results for different runs, unless the underlying collection type is ordered.
- returns
a pair consisting of the longest prefix of this iterable collection whose elements all satisfy
p
, and the rest of this iterable collection.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableLike → GenTraversableLike
-
def
splitAt(n: Int): (collection.Iterable[A], collection.Iterable[A])
Splits this iterable collection into two at a given position.
Splits this iterable collection into two at a given position. Note:
c splitAt n
is equivalent to (but possibly more efficient than)(c take n, c drop n)
.Note: might return different results for different runs, unless the underlying collection type is ordered.
- n
the position at which to split.
- returns
a pair of iterable collections consisting of the first
n
elements of this iterable collection, and the other elements.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableLike → GenTraversableLike
-
def
stringPrefix: String
Defines the prefix of this object's
toString
representation.Defines the prefix of this object's
toString
representation.- returns
a string representation which starts the result of
toString
applied to this iterable collection. By default the string prefix is the simple name of the collection class iterable collection.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableLike → GenTraversableLike
-
def
sum: A
[use case] Sums up the elements of this collection.
[use case]Sums up the elements of this collection.
- returns
the sum of all elements in this option of numbers of type
Int
. Instead ofInt
, any other typeT
with an implicitNumeric[T]
implementation can be used as element type of the option and as result type ofsum
. Examples of such types are:Long
,Float
,Double
,BigInt
.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
Full Signaturedef sum[B >: A](implicit num: Numeric[B]): B
-
final
def
synchronized[T0](arg0: ⇒ T0): T0
- Definition Classes
- AnyRef
-
def
tail: collection.Iterable[A]
Selects all elements except the first.
Selects all elements except the first.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- returns
a iterable collection consisting of all elements of this iterable collection except the first one.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableLike → GenTraversableLike
- Exceptions thrown
java.lang.UnsupportedOperationException
if the iterable collection is empty.
-
def
tails: collection.Iterator[collection.Iterable[A]]
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
.- returns
an iterator over all the tails of this iterable collection
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableLike
List(1,2,3).tails = Iterator(List(1,2,3), List(2,3), List(3), Nil)
Example: -
def
take(n: Int): collection.Iterable[A]
Selects first n elements.
Selects first n elements.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- 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 thann
elements. Ifn
is negative, returns an empty iterable collection.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- IterableLike → TraversableLike → GenTraversableLike
-
def
takeRight(n: Int): collection.Iterable[A]
Selects last n elements.
Selects last n elements.
Note: might return different results for different runs, unless the underlying collection type is ordered.
- n
the number of elements to take
- 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 thann
elements.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- IterableLike
-
def
takeWhile(p: (A) ⇒ Boolean): collection.Iterable[A]
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.
- returns
the longest prefix of this iterable collection whose elements all satisfy the predicate
p
.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- IterableLike → TraversableLike → GenTraversableLike
-
def
to[Col[_]]: Col[A]
[use case] Converts this option into another by copying all elements.
[use case]Converts this option into another by copying all elements.
- Col
The collection type to build.
- returns
a new collection containing all elements of this option.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableLike → TraversableOnce → GenTraversableOnce
Full Signaturedef to[Col[_]](implicit cbf: CanBuildFrom[Nothing, A, Col[A]]): Col[A]
-
def
toArray: Array[A]
[use case] Converts this option to an array.
[use case]Converts this option to an array.
- returns
an array containing all elements of this option. An
ClassTag
must be available for the element type of this option.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
-
def
toBuffer[B >: A]: Buffer[B]
Uses the contents of this iterable collection to create a new mutable buffer.
Uses the contents of this iterable collection to create a new mutable buffer.
Note: will not terminate for infinite-sized collections.
- returns
a buffer containing all elements of this iterable collection.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
-
def
toIndexedSeq: collection.immutable.IndexedSeq[A]
Converts this iterable collection to an indexed sequence.
Converts this iterable collection to an indexed sequence.
Note: will not terminate for infinite-sized collections.
- returns
an indexed sequence containing all elements of this iterable collection.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
-
def
toIterable: collection.Iterable[A]
Returns this iterable collection as an iterable collection.
Returns this iterable collection as an iterable collection.
A new collection will not be built; lazy collections will stay lazy.
Note: will not terminate for infinite-sized collections.
- returns
an
Iterable
containing all elements of this iterable collection.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- IterableLike → TraversableOnce → GenTraversableOnce
-
def
toIterator: collection.Iterator[A]
Returns an Iterator over the elements in this iterable collection.
Returns an Iterator over the elements in this iterable collection. Produces the same result as
iterator
.Note: will not terminate for infinite-sized collections.
- returns
an Iterator containing all elements of this iterable collection.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- IterableLike → TraversableLike → GenTraversableOnce
- Annotations
- @deprecatedOverriding( message = ... , since = "2.11.0" )
-
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) }
- right
the expression to evaluate and return if this is empty
-
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 }
- Definition Classes
- Option
-
def
toMap[T, U]: Map[T, U]
[use case] Converts this option to a map.
[use case]Converts this option to a map. This method is unavailable unless the elements are members of Tuple2, each ((T, U)) becoming a key-value pair in the map. Duplicate keys will be overwritten by later keys: if this is an unordered collection, which key is in the resulting map is undefined.
- returns
a map of type
immutable.Map[T, U]
containing all key/value pairs of type(T, U)
of this option.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
-
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) }
- left
the expression to evaluate and return if this is empty
-
def
toSeq: collection.Seq[A]
Converts this iterable collection to a sequence.
Converts this iterable collection to a sequence. As with
toIterable
, it's lazy in this default implementation, as thisTraversableOnce
may be lazy and unevaluated.Note: will not terminate for infinite-sized collections.
- returns
a sequence containing all elements of this iterable collection.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
-
def
toSet[B >: A]: Set[B]
Converts this iterable collection to a set.
Converts this iterable collection to a set.
Note: will not terminate for infinite-sized collections.
- returns
a set containing all elements of this iterable collection.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
-
def
toStream: collection.immutable.Stream[A]
Converts this iterable collection to a stream.
Converts this iterable collection to a stream.
- returns
a stream containing all elements of this iterable collection.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- IterableLike → TraversableLike → GenTraversableOnce
-
def
toString(): String
Converts this iterable collection to a string.
Converts this iterable collection to a string.
- returns
a string representation of this collection. By default this string consists of the
stringPrefix
of this iterable collection, followed by all elements separated by commas and enclosed in parentheses.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableLike → Any
-
def
toTraversable: collection.Traversable[A]
Converts this iterable collection to an unspecified Traversable.
Converts this iterable collection to an unspecified Traversable. Will return the same collection if this instance is already Traversable.
Note: will not terminate for infinite-sized collections.
- returns
a Traversable containing all elements of this iterable collection.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableLike → TraversableOnce → GenTraversableOnce
- Annotations
- @deprecatedOverriding( message = ... , since = "2.11.0" )
-
def
toVector: Vector[A]
Converts this iterable collection to a Vector.
Converts this iterable collection to a Vector.
Note: will not terminate for infinite-sized collections.
- returns
a vector containing all elements of this iterable collection.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
-
def
transpose[B](implicit asTraversable: (A) ⇒ GenTraversableOnce[B]): collection.Iterable[collection.Iterable[B]]
Transposes this iterable collection of traversable collections into a iterable collection of iterable collections.
Transposes this iterable collection of traversable 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))
- B
the type of the elements of each traversable collection.
- asTraversable
an implicit conversion which asserts that the element type of this iterable collection is a
Traversable
.- returns
a two-dimensional iterable collection of iterable collections which has as nth row the nth column of this iterable collection.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- GenericTraversableTemplate
- Annotations
- @migration
- Migration
(Changed in version 2.9.0)
transpose
throws anIllegalArgumentException
if collections are not uniformly sized.- Exceptions thrown
IllegalArgumentException
if all collections in this iterable collection are not of the same size.
-
def
unzip[A1, A2](implicit asPair: (A) ⇒ (A1, A2)): (collection.Iterable[A1], collection.Iterable[A2])
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))
- 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.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- GenericTraversableTemplate
-
def
unzip3[A1, A2, A3](implicit asTriple: (A) ⇒ (A1, A2, A3)): (collection.Iterable[A1], collection.Iterable[A2], collection.Iterable[A3])
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))
- 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.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- GenericTraversableTemplate
- val value: A
-
def
view(from: Int, until: Int): IterableView[A, collection.Iterable[A]]
Creates a non-strict view of a slice of this iterable collection.
Creates a non-strict view of a slice of this iterable collection.
Note: the difference between
view
andslice
is thatview
produces a view of the current iterable collection, whereasslice
produces a new iterable collection.Note:
view(from, to)
is equivalent toview.slice(from, to)
Note: might return different results for different runs, unless the underlying collection type is ordered.
- from
the index of the first element of the view
- until
the index of the element following the view
- returns
a non-strict view of a slice of this iterable collection, starting at index
from
and extending up to (but not including) indexuntil
.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- IterableLike → TraversableLike
-
def
view: IterableView[A, collection.Iterable[A]]
Creates a non-strict view of this iterable collection.
Creates a non-strict view of this iterable collection.
- returns
a non-strict view of this iterable collection.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- IterableLike → TraversableLike
-
final
def
wait(): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws( ... )
-
final
def
wait(arg0: Long, arg1: Int): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws( ... )
- final def wait(arg0: Long): Unit
-
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. -
def
zip[B](that: GenIterable[B]): Option[(A, B)]
[use case] Returns a option formed from this option and another iterable collection by combining corresponding elements in pairs.
[use case]Returns a option formed from this option 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.
- 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 option containing pairs consisting of corresponding elements of this option and
that
. The length of the returned collection is the minimum of the lengths of this option andthat
.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- IterableLike → GenIterableLike
Full Signaturedef zip[A1 >: A, B, That](that: GenIterable[B])(implicit bf: CanBuildFrom[collection.Iterable[A], (A1, B), That]): That
-
def
zipAll[B](that: collection.Iterable[B], thisElem: A, thatElem: B): Option[(A, B)]
[use case] Returns a option formed from this option and another iterable collection by combining corresponding elements in pairs.
[use case]Returns a option formed from this option 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.
- B
the type of the second half of the returned pairs
- that
The iterable providing the second half of each result pair
- thisElem
the element to be used to fill up the result if this option is shorter than
that
.- thatElem
the element to be used to fill up the result if
that
is shorter than this option.- returns
a new option containing pairs consisting of corresponding elements of this option and
that
. The length of the returned collection is the maximum of the lengths of this option andthat
. If this option is shorter thanthat
,thisElem
values are used to pad the result. Ifthat
is shorter than this option,thatElem
values are used to pad the result.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- IterableLike → GenIterableLike
Full Signaturedef zipAll[B, A1 >: A, That](that: GenIterable[B], thisElem: A1, thatElem: B)(implicit bf: CanBuildFrom[collection.Iterable[A], (A1, B), That]): That
-
def
zipWithIndex: Option[(A, Int)]
[use case] Zips this option with its indices.
[use case]Zips this option with its indices.
- returns
A new option containing pairs consisting of all elements of this option paired with their index. Indices start at
0
.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- IterableLike → GenIterableLike
List("a", "b", "c").zipWithIndex = List(("a", 0), ("b", 1), ("c", 2))
Full Signaturedef zipWithIndex[A1 >: A, That](implicit bf: CanBuildFrom[collection.Iterable[A], (A1, Int), That]): That
Example: -
def
→[B](y: B): (Some[A], B)
- Implicit
- This member is added by an implicit conversion from Some[A] to ArrowAssoc[Some[A]] performed by method ArrowAssoc in scala.Predef.
- Definition Classes
- ArrowAssoc
Shadowed Implicit Value Members
-
def
collect[B](pf: PartialFunction[A, B]): Option[B]
[use case] Builds a new collection by applying a partial function to all elements of this option on which the function is defined.
[use case]Builds a new collection by applying a partial function to all elements of this option on which the function is defined.
- B
the element type of the returned collection.
- pf
the partial function which filters and maps the option.
- returns
a new option 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.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(some: Iterable[A]).collect(pf)
- Definition Classes
- TraversableLike → GenTraversableLike
Full Signaturedef collect[B, That](pf: PartialFunction[A, B])(implicit bf: CanBuildFrom[collection.Iterable[A], B, That]): That
-
def
exists(p: (A) ⇒ Boolean): Boolean
Tests whether a predicate holds for at least one element of this iterable collection.
Tests whether a predicate holds for at least one element of this iterable collection.
Note: may not terminate for infinite-sized collections.
- p
the predicate used to test elements.
- returns
false
if this iterable collection is empty, otherwisetrue
if the given predicatep
holds for some of the elements of this iterable collection, otherwisefalse
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(some: Iterable[A]).exists(p)
- Definition Classes
- IterableLike → TraversableLike → TraversableOnce → GenTraversableOnce
-
def
filter(p: (A) ⇒ Boolean): collection.Iterable[A]
Selects all elements of this iterable collection which satisfy a predicate.
Selects all elements of this iterable collection which satisfy a predicate.
- 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.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(some: Iterable[A]).filter(p)
- Definition Classes
- TraversableLike → GenTraversableLike
-
def
filterNot(p: (A) ⇒ Boolean): collection.Iterable[A]
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.
- p
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
p
. The order of the elements is preserved.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(some: Iterable[A]).filterNot(p)
- Definition Classes
- TraversableLike → GenTraversableLike
-
def
flatMap[B](f: (A) ⇒ GenTraversableOnce[B]): Option[B]
[use case] Builds a new collection by applying a function to all elements of this option and using the elements of the resulting collections.
[use case]Builds a new collection by applying a function to all elements of this option 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 option. 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 => 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)
- B
the element type of the returned collection.
- f
the function to apply to each element.
- returns
a new option resulting from applying the given collection-valued function
f
to each element of this option and concatenating the results.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(some: Iterable[A]).flatMap(f)
- Definition Classes
- TraversableLike → GenTraversableLike → FilterMonadic
Full Signaturedef flatMap[B, That](f: (A) ⇒ GenTraversableOnce[B])(implicit bf: CanBuildFrom[collection.Iterable[A], B, That]): That
-
def
flatten[B]: Option[B]
[use case] Converts this option of traversable collections into a option formed by the elements of these traversable collections.
[use case]Converts this option of traversable collections into a option formed by the elements of these traversable collections.
The resulting collection's type will be guided by the static type of option. 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)
- B
the type of the elements of each traversable collection.
- returns
a new option resulting from concatenating all element options.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(some: Iterable[A]).flatten
- Definition Classes
- GenericTraversableTemplate
Full Signaturedef flatten[B](implicit asTraversable: (A) ⇒ GenTraversableOnce[B]): collection.Iterable[B]
-
def
fold[A1 >: A](z: A1)(op: (A1, A1) ⇒ A1): A1
Folds the elements of this iterable collection using the specified associative binary operator.
Folds the elements of this iterable collection using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
Note: will not terminate for infinite-sized collections.
- A1
a type parameter for the binary operator, a supertype of
A
.- 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).- op
a binary operator that must be associative.
- returns
the result of applying the fold operator
op
between all the elements andz
, orz
if this iterable collection is empty.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(some: Iterable[A]).fold(z)(op)
- Definition Classes
- TraversableOnce → GenTraversableOnce
-
def
forall(p: (A) ⇒ Boolean): Boolean
Tests whether a predicate holds for all elements of this iterable collection.
Tests whether a predicate holds for all elements of this iterable collection.
Note: may not terminate for infinite-sized collections.
- p
the predicate used to test elements.
- returns
true
if this iterable collection is empty or the given predicatep
holds for all elements of this iterable collection, otherwisefalse
.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(some: Iterable[A]).forall(p)
- Definition Classes
- IterableLike → TraversableLike → TraversableOnce → GenTraversableOnce
-
def
foreach(f: (A) ⇒ Unit): Unit
[use case] Applies a function
f
to all elements of this option.[use case]Applies a function
f
to all elements of this option.Note: this method underlies the implementation of most other bulk operations. Subclasses should re-implement this method if a more efficient implementation exists.
- f
the function that is applied for its side-effect to every element. The result of function
f
is discarded.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(some: Iterable[A]).foreach(f)
- Definition Classes
- IterableLike → TraversableLike → GenTraversableLike → TraversableOnce → GenTraversableOnce → FilterMonadic
Full Signaturedef foreach[U](f: (A) ⇒ U): Unit
-
def
isEmpty: Boolean
Tests whether this iterable collection is empty.
Tests whether this iterable collection is empty.
- returns
true
if the iterable collection contain no elements,false
otherwise.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(some: Iterable[A]).isEmpty
- Definition Classes
- IterableLike → TraversableLike → TraversableOnce → GenTraversableOnce
-
def
iterator: collection.Iterator[A]
Creates a new iterator over all elements contained in this iterable object.
Creates a new iterator over all elements contained in this iterable object.
- returns
the new iterator
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(some: Iterable[A]).iterator
- Definition Classes
- IterableLike → GenIterableLike
-
def
map[B](f: (A) ⇒ B): Option[B]
[use case] Builds a new collection by applying a function to all elements of this option.
[use case]Builds a new collection by applying a function to all elements of this option.
- B
the element type of the returned collection.
- f
the function to apply to each element.
- returns
a new option resulting from applying the given function
f
to each element of this option and collecting the results.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(some: Iterable[A]).map(f)
- Definition Classes
- TraversableLike → GenTraversableLike → FilterMonadic
Full Signaturedef map[B, That](f: (A) ⇒ B)(implicit bf: CanBuildFrom[collection.Iterable[A], B, That]): That
-
def
nonEmpty: Boolean
Tests whether the iterable collection is not empty.
Tests whether the iterable collection is not empty.
- returns
true
if the iterable collection contains at least one element,false
otherwise.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(some: Iterable[A]).nonEmpty
- Definition Classes
- TraversableOnce → GenTraversableOnce
-
def
toList: List[A]
Converts this iterable collection to a list.
Converts this iterable collection to a list.
Note: will not terminate for infinite-sized collections.
- returns
a list containing all elements of this iterable collection.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(some: Iterable[A]).toList
- Definition Classes
- TraversableOnce → GenTraversableOnce
-
def
withFilter(p: (A) ⇒ Boolean): FilterMonadic[A, collection.Iterable[A]]
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
andc withFilter p
is that the former creates a new collection, whereas the latter only restricts the domain of subsequentmap
,flatMap
,foreach
, andwithFilter
operations.Note: might return different results for different runs, unless the underlying collection type is ordered.
- p
the predicate used to test elements.
- returns
an object of class
WithFilter
, which supportsmap
,flatMap
,foreach
, andwithFilter
operations. All these operations apply to those elements of this iterable collection which satisfy the predicatep
.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(some: Iterable[A]).withFilter(p)
- Definition Classes
- TraversableLike → FilterMonadic
Deprecated Value Members
-
def
/:[B](z: B)(op: (B, A) ⇒ B): B
Applies a binary operator to a start value and all elements of this iterable collection, going left to right.
Applies a binary operator to a start value and all elements of this iterable collection, going left to right.
Note:
/:
is alternate syntax forfoldLeft
;z /: xs
is the same asxs foldLeft z
.Examples:
Note that the folding function used to compute b is equivalent to that used to compute c.
scala> val a = List(1,2,3,4) a: List[Int] = List(1, 2, 3, 4) scala> val b = (5 /: a)(_+_) b: Int = 15 scala> val c = (5 /: a)((x,y) => x + y) c: Int = 15
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.
- B
the result type of the binary operator.
- z
the start value.
- op
the binary operator.
- returns
the result of inserting
op
between consecutive elements of this iterable collection, going left to right with the start valuez
on the left:op(...op(op(z, x_1), x_2), ..., x_n)
where
x1, ..., xn
are the elements of this iterable collection.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
- Annotations
- @deprecated
- Deprecated
(Since version 2.12.10) Use foldLeft instead of /:
-
def
:\[B](z: B)(op: (A, B) ⇒ B): B
Applies a binary operator to all elements of this iterable collection and a start value, going right to left.
Applies a binary operator to all elements of this iterable collection and a start value, going right to left.
Note:
:\
is alternate syntax forfoldRight
;xs :\ z
is the same asxs foldRight z
.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.
Examples:
Note that the folding function used to compute b is equivalent to that used to compute c.
scala> val a = List(1,2,3,4) a: List[Int] = List(1, 2, 3, 4) scala> val b = (a :\ 5)(_+_) b: Int = 15 scala> val c = (a :\ 5)((x,y) => x + y) c: Int = 15
- B
the result type of the binary operator.
- z
the start value
- op
the binary operator
- returns
the result of inserting
op
between consecutive elements of this iterable collection, going right to left with the start valuez
on the right:op(x_1, op(x_2, ... op(x_n, z)...))
where
x1, ..., xn
are the elements of this iterable collection.
- Implicit
- This member is added by an implicit conversion from Some[A] to Iterable[A] performed by method option2Iterable in scala.Option.
- Definition Classes
- TraversableOnce → GenTraversableOnce
- Annotations
- @deprecated
- Deprecated
(Since version 2.12.10) Use foldRight instead of :\
-
def
x: A
- Annotations
- @deprecated
- Deprecated
(Since version 2.12.0) Use .value instead.
This is the documentation for the Scala standard library.
Package structure
The scala package contains core types like
Int
,Float
,Array
orOption
which are accessible in all Scala compilation units without explicit qualification or imports.Notable packages include:
scala.collection
and its sub-packages contain Scala's collections frameworkscala.collection.immutable
- Immutable, sequential data-structures such asVector
,List
,Range
,HashMap
orHashSet
scala.collection.mutable
- Mutable, sequential data-structures such asArrayBuffer
,StringBuilder
,HashMap
orHashSet
scala.collection.concurrent
- Mutable, concurrent data-structures such asTrieMap
scala.collection.parallel.immutable
- Immutable, parallel data-structures such asParVector
,ParRange
,ParHashMap
orParHashSet
scala.collection.parallel.mutable
- Mutable, parallel data-structures such asParArray
,ParHashMap
,ParTrieMap
orParHashSet
scala.concurrent
- Primitives for concurrent programming such asFutures
andPromises
scala.io
- Input and output operationsscala.math
- Basic math functions and additional numeric types likeBigInt
andBigDecimal
scala.sys
- Interaction with other processes and the operating systemscala.util.matching
- Regular expressionsOther packages exist. See the complete list on the right.
Additional parts of the standard library are shipped as separate libraries. These include:
scala.reflect
- Scala's reflection API (scala-reflect.jar)scala.xml
- XML parsing, manipulation, and serialization (scala-xml.jar)scala.swing
- A convenient wrapper around Java's GUI framework called Swing (scala-swing.jar)scala.util.parsing
- Parser combinators (scala-parser-combinators.jar)Automatic imports
Identifiers in the scala package and the
scala.Predef
object are always in scope by default.Some of these identifiers are type aliases provided as shortcuts to commonly used classes. For example,
List
is an alias forscala.collection.immutable.List
.Other aliases refer to classes provided by the underlying platform. For example, on the JVM,
String
is an alias forjava.lang.String
.