List

trait DefaultSerializable

trait Serializable

trait StrictOptimizedSeqOps[A, List, List[A]]

trait StrictOptimizedLinearSeqOps[A, List, List[A]]

trait StrictOptimizedSeqOps[A, List, List[A]]

trait StrictOptimizedIterableOps[A, List, List[A]]

trait LinearSeq[A]

trait LinearSeqOps[A, List, List[A]]

trait LinearSeq[A]

trait LinearSeqOps[A, List, List[A]]

class AbstractSeq[A]

trait Seq[A]

trait SeqOps[A, List, List[A]]

trait Iterable[A]

class AbstractSeq[A]

trait Seq[A]

trait Equals

trait SeqOps[A, List, List[A]]

trait PartialFunction[Int, A]

trait Int => A

class AbstractIterable[A]

trait Iterable[A]

trait IterableFactoryDefaults[A, List]

trait IterableOps[A, List, List[A]]

trait IterableOnceOps[A, List, List[A]]

trait IterableOnce[A]

class Object

trait Matchable

class Any

class ::[A]

object Nil.type

Value members

Concrete methods

Adds an element at the beginning of this list.

Value parameters:

elem: the element to prepend.

Returns:

a list which contains x as first element and which continues with this list. Example:

1 :: List(2, 3) = List(2, 3).::(1) = List(1, 2, 3)

Source:

Adds the elements of a given list in front of this list.

Example:

List(1, 2) ::: List(3, 4) = List(3, 4).:::(List(1, 2)) = List(1, 2, 3, 4)

Value parameters:

prefix: The list elements to prepend.

Returns:

a list resulting from the concatenation of the given list prefix and this list.

Source:

Returns a new list containing the elements from the left hand operand followed by the elements from the right hand operand.

Returns a new list containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the list is the most specific superclass encompassing the element types of the two operands.

Type parameters:

B: the element type of the returned collection.

Value parameters:

suffix: the iterable to append.

Returns:

a new collection of type CC[B] which contains all elements of this list followed by all elements of suffix.

Definition Classes

Source:

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

Type parameters:

B: the element type of the returned list.

Value parameters:

pf: the partial function which filters and maps the list.

Returns:

a new list 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.

Definition Classes

StrictOptimizedIterableOps -> IterableOps -> IterableOnceOps

Source:

Tests whether this list contains a given value as an element.

Value parameters:

elem: the element to test.

Returns:

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

Definition Classes

Source:

Tests whether every element of this list relates to the corresponding element of another sequence by satisfying a test predicate.

Type parameters:

B: the type of the elements of that

Value parameters:

p: the test predicate, which relates elements from both sequences
that: the other sequence

Returns:

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

Definition Classes

Source:

The universal equality method defined in AnyRef.

Definition Classes: Seq -> Equals -> Any
Source:: List.scala

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

Value parameters:

p: the predicate used to test elements.

Returns:

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

Definition Classes

Source:

Selects all elements of this list which satisfy a predicate.

Value parameters:

p: the predicate used to test elements.

Returns:

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

Definition Classes

StrictOptimizedIterableOps -> IterableOps -> IterableOnceOps

Source:

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

Value parameters:

pred: the predicate used to test elements.

Returns:

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

Definition Classes

StrictOptimizedIterableOps -> IterableOps -> IterableOnceOps

Source:

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

Value parameters:

p: the predicate used to test elements.

Returns:

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

Definition Classes

Source:

Builds a new list by applying a function to all elements of this list 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 list. This might cause unexpected results sometimes. For example:

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

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

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

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

Type parameters:

B: the element type of the returned collection.

Value parameters:

f: the function to apply to each element.

Returns:

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

Definition Classes

StrictOptimizedIterableOps -> IterableOps -> IterableOnceOps

Source:

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

Type parameters:

B: the result type of the binary operator.

Value parameters:

op: the binary operator.
z: the start value.

Returns:

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

Definition Classes

Source:

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

Value parameters:

p: the predicate used to test elements.

Returns:

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

Definition Classes

Source:

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

Definition Classes: LinearSeqOps -> IterableOnceOps
Source:: List.scala

Tests whether the list is empty.

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

Returns:: true if the list contains no elements, false otherwise.
Definition Classes: LinearSeqOps -> SeqOps -> IterableOnceOps
Source:: List.scala

The companion object of this list, providing various factory methods.

Note:: When implementing a custom collection type and refining CC to the new type, this method needs to be overridden to return a factory for the new type (the compiler will issue an error otherwise).
Definition Classes: LinearSeq -> LinearSeq -> Seq -> Iterable -> Seq -> Iterable -> IterableOps
Source:: List.scala

Selects the last element.

Returns:

The last element of this list.

Throws:

NoSuchElementException: If the list is empty.

Definition Classes

LinearSeqOps -> IterableOps

Source:

The length (number of elements) of the list.

The length (number of elements) of the list. size is an alias for length in Seq collections.

Definition Classes: LinearSeqOps -> SeqOps
Source:: List.scala

Compares the length of this list to a test value.

Value parameters:

len: the test value that gets compared with the length.

Returns:

A value x where

x <  0       if this.length <  len
x == 0       if this.length == len
x >  0       if this.length >  len

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

See also:

lengthIs

Definition Classes

Source:

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

Type parameters:

B: the element type of the returned list.

Value parameters:

f: the function to apply to each element.

Returns:

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

Definition Classes

StrictOptimizedIterableOps -> IterableOps -> IterableOnceOps

Source:

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

Builds a new list by applying a function to all elements of this list. Like xs map f, but returns xs unchanged if function f maps all elements to themselves (as determined by eq).

Type parameters:

B: the element type of the returned collection.

Value parameters:

f: the function to apply to each element.

Returns:

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

Source:

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

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

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

Definition Classes: StrictOptimizedIterableOps -> IterableOps
Source:: List.scala

A copy of the list with an element prepended.

Also, the original list is not modified, so you will want to capture the result.

Example:

scala> val x = List(1)
x: List[Int] = List(1)

scala> val y = 2 +: x
y: List[Int] = List(2, 1)

scala> println(x)
List(1)

Type parameters:

B: the element type of the returned list.

Value parameters:

elem: the prepended element

Returns:

a new list consisting of value followed by all elements of this list.

Definition Classes

Source:

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.

Type parameters:

B: the element type of the returned collection.

Value parameters:

prefix: the iterable to prepend.

Returns:

a new list which contains all elements of prefix followed by all the elements of this list.

Definition Classes

Source:

Returns new list with elements in reversed order.

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

Returns:: A new list with all elements of this list in reversed order.
Definition Classes: SeqOps
Source:: List.scala

Adds the elements of a given list in reverse order in front of this list.

Adds the elements of a given list in reverse order in front of this list. xs reverse_::: ys is equivalent to xs.reverse ::: ys but is more efficient.

Value parameters:

prefix: the prefix to reverse and then prepend

Returns:

the concatenation of the reversed prefix and the current list.

Source:

Example:

// Given a list
val letters = List('a','b','c','d','e')
// `slice` returns all elements beginning at index `from` and afterwards,
// up until index `until` (excluding index `until`.)
letters.slice(1,3) // Returns List('b','c')

Definition Classes

Source:

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

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

Value parameters:

p: the test predicate

Returns:

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

Definition Classes

StrictOptimizedIterableOps -> IterableOps -> IterableOnceOps

Source:

Splits this list into a prefix/suffix pair at a given position.

Note: c splitAt n is equivalent to (but possibly more efficient than) (c take n, c drop n).

Value parameters:

n: the position at which to split.

Returns:

a pair of lists consisting of the first n elements of this list, and the other elements.

Definition Classes

Source:

Selects the first n elements.

Value parameters:

n: the number of elements to take from this list.

Returns:

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

Definition Classes

Source:

A collection containing the last n elements of this collection.

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

Definition Classes: StrictOptimizedIterableOps -> IterableOps
Source:: List.scala

Takes longest prefix of elements that satisfy a predicate.

Value parameters:

p: The predicate used to test elements.

Returns:

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

Definition Classes

Source:

Definition Classes: IterableOnceOps
Source:: List.scala

A copy of this list with one single replaced element.

Type parameters:

B: the element type of the returned list.

Value parameters:

elem: the replacing element
index: the position of the replacement

Returns:

a new list which is a copy of this list with the element at position index replaced by elem.

Throws:

IndexOutOfBoundsException: if index does not satisfy 0 <= index < length. In case of a lazy collection this exception may be thrown at a later time or not at all (if the end of the collection is never evaluated).

Definition Classes

Source:

Inherited methods

Alias for concat

Inherited from:: IterableOps
Source:: Iterable.scala

Alias for prependedAll

Definition Classes: SeqOps -> IterableOps
Inherited from:: SeqOps
Source:: Seq.scala

Alias for prepended.

Note that :-ending operators are right associative (see example). A mnemonic for +: vs. :+ is: the COLon goes on the COLlection side.

Inherited from:: SeqOps
Source:: Seq.scala

Alias for appended

Note that :-ending operators are right associative (see example). A mnemonic for +: vs. :+ is: the COLon goes on the COLlection side.

Inherited from:: SeqOps
Source:: Seq.scala

Alias for appendedAll

Inherited from:: SeqOps
Source:: Seq.scala

Appends all elements of this collection to a string builder.

Appends all elements of this collection to a string builder. The written text consists of the string representations (w.r.t. the method toString) of all elements of this collection without any separator string.

Example:

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

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

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

Value parameters:

b: the string builder to which elements are appended.

Returns:

the string builder b to which elements were appended.

Inherited from:

Source:

Appends all elements of this collection to a string builder using a separator string.

Appends all elements of this collection to a string builder using a separator string. The written text consists of the string representations (w.r.t. the method toString) of all elements of this collection, separated by the string sep.

Example:

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

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

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

Value parameters:

b: the string builder to which elements are appended.
sep: the separator string.

Returns:

the string builder b to which elements were appended.

Inherited from:

Source:

Appends all elements of this collection to a string builder using start, end, and separator strings.

Appends all elements of this collection to a string builder using start, end, and separator strings. The written text begins with the string start and ends with the string end. Inside, the string representations (w.r.t. the method toString) of all elements of this collection are separated by the string sep.

Example:

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

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

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

Value parameters:

b: the string builder to which elements are appended.
end: the ending string.
sep: the separator string.
start: the starting string.

Returns:

the string builder b to which elements were appended.

Inherited from:

Source:

Composes this partial function with another partial function that gets applied to results of this partial function.

Note that calling isDefinedAt on the resulting partial function may apply the first partial function and execute its side effect. For efficiency, it is recommended to call applyOrElse instead of isDefinedAt or apply.

Type parameters:

C: the result type of the transformation function.

Value parameters:

k: the transformation function

Returns:

a partial function with the domain of this partial function narrowed by other partial function, which maps arguments x to k(this(x)).

Inherited from:

Source:

Composes this partial function with a transformation function that gets applied to results of this partial function.

If the runtime type of the function is a PartialFunction then the other andThen method is used (note its cautions).

Type parameters:

C: the result type of the transformation function.

Value parameters:

k: the transformation function

Returns:

a partial function with the domain of this partial function, possibly narrowed by the specified function, which maps arguments x to k(this(x)).

Definition Classes

PartialFunction -> Function1

Inherited from:

Source:

A copy of this sequence with an element appended.

Note: will not terminate for infinite-sized collections.

Example:

scala> val a = List(1)
a: List[Int] = List(1)

scala> val b = a :+ 2
b: List[Int] = List(1, 2)

scala> println(a)
List(1)

Type parameters:

B: the element type of the returned sequence.

Value parameters:

elem: the appended element

Returns:

a new sequence consisting of all elements of this sequence followed by value.

Definition Classes

Inherited from:

Source:

@throws(scala.throws.$lessinit$greater$default$1[scala.IndexOutOfBoundsException])

Get the element at the specified index.

Get the element at the specified index. This operation is provided for convenience in Seq. It should not be assumed to be efficient unless you have an IndexedSeq.

Definition Classes: LinearSeqOps -> SeqOps
Inherited from:: LinearSeqOps
Source:: LinearSeq.scala

Applies this partial function to the given argument when it is contained in the function domain.

Applies this partial function to the given argument when it is contained in the function domain. Applies fallback function where this partial function is not defined.

Note that expression pf.applyOrElse(x, default) is equivalent to

if(pf isDefinedAt x) pf(x) else default(x)

except that applyOrElse method can be implemented more efficiently. For all partial function literals the compiler generates an applyOrElse implementation which avoids double evaluation of pattern matchers and guards. This makes applyOrElse the basis for the efficient implementation for many operations and scenarios, such as:

- combining partial functions into orElse/andThen chains does not lead to excessive apply/isDefinedAt evaluation - lift and unlift do not evaluate source functions twice on each invocation - runWith allows efficient imperative-style combining of partial functions with conditionally applied actions

For non-literal partial function classes with nontrivial isDefinedAt method it is recommended to override applyOrElse with custom implementation that avoids double isDefinedAt evaluation. This may result in better performance and more predictable behavior w.r.t. side effects.

Value parameters:

default: the fallback function
x: the function argument

Returns:

the result of this function or fallback function application.

Inherited from:

Source:

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

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

Value parameters:

that: the value being probed for possible equality

Returns:

true if this instance can possibly equal that, otherwise false

Inherited from:

Seq

Source:

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

Note: may not terminate for infinite-sized collections.

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

Value parameters:

pf: the partial function

Returns:

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

Example:

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

Inherited from:

Source:

Iterates over combinations.

Iterates over combinations. A _combination_ of length n is a subsequence of the original sequence, with the elements taken in order. Thus, "xy" and "yy" are both length-2 combinations of "xyy", but "yx" is not. If there is more than one way to generate the same subsequence, only one will be returned.

For example, "xyyy" has three different ways to generate "xy" depending on whether the first, second, or third "y" is selected. However, since all are identical, only one will be chosen. Which of the three will be taken is an implementation detail that is not defined.

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

Returns:: An Iterator which traverses the possible n-element combinations of this sequence.
Example:: "abbbc".combinations(2) = Iterator(ab, ac, bb, bc)
Inherited from:: SeqOps
Source:: Seq.scala

Composes another partial function k with this partial function so that this partial function gets applied to results of k.

Type parameters:

R: the parameter type of the transformation function.

Value parameters:

k: the transformation function

Returns:

a partial function with the domain of other partial function narrowed by this partial function, which maps arguments x to this(k(x)).

Inherited from:

Source:

@unspecialized

Composes two instances of Function1 in a new Function1, with this function applied last.

Type parameters:

A: the type to which function g can be applied

Value parameters:

g: a function A => T1

Returns:

a new function f such that f(x) == apply(g(x))

Inherited from:

Function1

Source:

Function1.scala

Returns a new sequence containing the elements from the left hand operand followed by the elements from the right hand operand.

Returns a new sequence containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the sequence is the most specific superclass encompassing the element types of the two operands.

Type parameters:

B: the element type of the returned collection.

Value parameters:

suffix: the traversable to append.

Returns:

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

Definition Classes

SeqOps -> IterableOps

Inherited from:

Source:

Tests whether this sequence contains a given sequence as a slice.

Note: may not terminate for infinite-sized collections.

Value parameters:

that: the sequence to test

Returns:

true if this sequence contains a slice with the same elements as that, otherwise false.

Inherited from:

Source:

Copy elements to an array, returning the number of elements written.

Fills the given array xs starting at index start with at most len elements of this collection.

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

Type parameters:

B: the type of the elements of the array.

Value parameters:

len: the maximal number of elements to copy.
start: the starting index of xs.
xs: the array to fill.

Returns:

the number of elements written to the array

Note:

Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change.

Inherited from:

Source:

@deprecatedOverriding("This should always forward to the 3-arg version of this method", since = "2.13.4")

Copy elements to an array, returning the number of elements written.

Fills the given array xs starting at index start with values of this collection.

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

Type parameters:

B: the type of the elements of the array.

Value parameters:

start: the starting index of xs.
xs: the array to fill.

Returns:

the number of elements written to the array

Note:

Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change.

Inherited from:

Source:

@deprecatedOverriding("This should always forward to the 3-arg version of this method", since = "2.13.4")

Copy elements to an array, returning the number of elements written.

Fills the given array xs starting at index start with values of this collection.

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

Type parameters:

B: the type of the elements of the array.

Value parameters:

xs: the array to fill.

Returns:

the number of elements written to the array

Note:

Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change.

Inherited from:

Source:

Tests whether every element of this collection's iterator relates to the corresponding element of another collection by satisfying a test predicate.

Note: will not terminate for infinite-sized collections.

Type parameters:

B: the type of the elements of that

Value parameters:

p: the test predicate, which relates elements from both collections
that: the other collection

Returns:

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

Inherited from:

Source:

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

Note: will not terminate for infinite-sized collections.

Value parameters:

p: the predicate used to test elements.

Returns:

the number of elements satisfying the predicate p.

Inherited from:

Source:

Computes the multiset difference between this sequence and another sequence.

Value parameters:

that: the sequence of elements to remove

Returns:

a new sequence which contains all elements of this sequence except some of occurrences of elements that also appear in that. If an element value x appears n times in that, then the first n occurrences of x will not form part of the result, but any following occurrences will.

Definition Classes

Inherited from:

Source:

Selects all the elements of this sequence ignoring the duplicates.

Returns:: a new sequence consisting of all the elements of this sequence without duplicates.
Inherited from:: SeqOps
Source:: Seq.scala

Selects all the elements of this sequence ignoring the duplicates as determined by == after applying the transforming function f.

Type parameters:

B: the type of the elements after being transformed by f

Value parameters:

f: The transforming function whose result is used to determine the uniqueness of each element

Returns:

a new sequence consisting of all the elements of this sequence without duplicates.

Definition Classes

StrictOptimizedSeqOps -> StrictOptimizedSeqOps -> SeqOps

Inherited from:

Source:

StrictOptimizedLinearSeqOps

Selects all elements except first n ones.

Value parameters:

n: the number of elements to drop from this sequence.

Returns:

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

Definition Classes

StrictOptimizedLinearSeqOps -> IterableOps -> IterableOnceOps

Inherited from:

Source:

StrictOptimizedLinearSeqOps

The rest of the collection without its n last elements.

The rest of the collection without its n last elements. For linear, immutable collections this should avoid making a copy.

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

Definition Classes: StrictOptimizedIterableOps -> IterableOps
Inherited from:: StrictOptimizedIterableOps
Source:: StrictOptimizedIterableOps.scala

Drops longest prefix of elements that satisfy a predicate.

Value parameters:

p: The predicate used to test elements.

Returns:

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

Definition Classes

StrictOptimizedLinearSeqOps -> IterableOps -> IterableOnceOps

Inherited from:

Source:

Returns an extractor object with a unapplySeq method, which extracts each element of a sequence data.

Example:

val firstChar: String => Option[Char] = _.headOption
Seq("foo", "bar", "baz") match {
  case firstChar.unlift.elementWise(c0, c1, c2) =>
    println(s"$c0, $c1, $c2") // Output: f, b, b
}

Inherited from:

Source:

The empty iterable of the same type as this iterable

Returns:: an empty iterable of type C.
Definition Classes: IterableFactoryDefaults -> IterableOps
Inherited from:: IterableFactoryDefaults
Source:: Iterable.scala

Tests whether this sequence ends with the given sequence.

Note: will not terminate for infinite-sized collections.

Value parameters:

that: the sequence to test

Returns:

true if this sequence has that as a suffix, false otherwise.

Inherited from:

Source:

Finds the last element of the sequence satisfying a predicate, if any.

Note: will not terminate for infinite-sized collections.

Value parameters:

p: the predicate used to test elements.

Returns:

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

Definition Classes

Inherited from:

Source:

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

The resulting collection's type will be guided by the type of iterable collection. For example:

val xs = List(
           Set(1, 2, 3),
           Set(1, 2, 3)
         ).flatten
// xs == List(1, 2, 3, 1, 2, 3)

val ys = Set(
           List(1, 2, 3),
           List(3, 2, 1)
         ).flatten
// ys == Set(1, 2, 3)

Type parameters:

B: the type of the elements of each traversable collection.

Value parameters:

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

Returns:

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

Definition Classes

StrictOptimizedIterableOps -> IterableOps -> IterableOnceOps

Inherited from:

Source:

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

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

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

Note: will not terminate for infinite-sized collections.

Type parameters:

A1: a type parameter for the binary operator, a supertype of A.

Value parameters:

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

Returns:

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

Inherited from:

Source:

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

Note: will not terminate for infinite-sized collections.

Type parameters:

B: the result type of the binary operator.

Value parameters:

op: the binary operator.
z: the start value.

Returns:

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

Definition Classes

Inherited from:

Source:

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

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

Note:: When implementing a custom collection type and refining C to the new type, this method needs to be overridden (the compiler will issue an error otherwise). In the common case where C =:= CC[A], this can be done by mixing in the scala.collection.IterableFactoryDefaults trait, which implements the method using iterableFactory.
As witnessed by the @uncheckedVariance annotation, using this method might be unsound. However, as long as it is called with an Iterable[A] obtained from this collection (as it is the case in the implementations of operations where we use a View[A]), it is safe.
Inherited from:: IterableFactoryDefaults
Source:: Iterable.scala

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

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

Type parameters:

K: the type of keys returned by the discriminator function.

Value parameters:

f: the discriminator function.

Returns:

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

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

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

Inherited from:

Source:

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

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

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

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

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

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

Type parameters:

B: the type of values returned by the transformation function
K: the type of keys returned by the discriminator function

Value parameters:

f: the element transformation function
key: the discriminator function

Inherited from:

Source:

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

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

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

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

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

Inherited from:: IterableOps
Source:: Iterable.scala

Partitions elements in fixed size iterable collections.

Value parameters:

size: the number of elements per group

Returns:

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

See also:

scala.collection.Iterator, method grouped

Inherited from:

Source:

Calculate a hash code value for the object.

The default hashing algorithm is platform dependent.

Note that it is allowed for two objects to have identical hash codes (o1.hashCode.equals(o2.hashCode)) yet not be equal (o1.equals(o2) returns false). A degenerate implementation could always return 0. However, it is required that if two objects are equal (o1.equals(o2) returns true) that they have identical hash codes (o1.hashCode.equals(o2.hashCode)). Therefore, when overriding this method, be sure to verify that the behavior is consistent with the equals method.

Returns:: the hash code value for this object.
Definition Classes: Seq -> Any
Inherited from:: Seq
Source:: Seq.scala

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.

Throws:

NoSuchElementException: if the iterable collection is empty.

Inherited from:

Source:

Optionally selects the first element.

Returns:: the first element of this sequence if it is nonempty, None if it is empty.
Definition Classes: LinearSeqOps -> IterableOps
Inherited from:: LinearSeqOps
Source:: LinearSeq.scala

@deprecatedOverriding("Override indexOf(elem, from) instead - indexOf(elem) calls indexOf(elem, 0)", "2.13.0")

Finds index of first occurrence of some value in this sequence.

Type parameters:

B: the type of the element elem.

Value parameters:

elem: the element value to search for.

Returns:

the index >= 0 of the first element of this sequence that is equal (as determined by ==) to elem, or -1, if none exists.

Inherited from:

Source:

Finds index of first occurrence of some value in this sequence after or at some start index.

Type parameters:

B: the type of the element elem.

Value parameters:

elem: the element value to search for.
from: the start index

Returns:

the index >= from of the first element of this sequence that is equal (as determined by ==) to elem, or -1, if none exists.

Inherited from:

Source:

@deprecatedOverriding("Override indexOfSlice(that, from) instead - indexOfSlice(that) calls indexOfSlice(that, 0)", "2.13.0")

Finds first index where this sequence contains a given sequence as a slice.

Note: may not terminate for infinite-sized collections.

Value parameters:

that: the sequence to test

Returns:

the first index >= 0 such that the elements of this sequence starting at this index match the elements of sequence that, or -1 of no such subsequence exists.

Inherited from:

Source:

Finds first index after or at a start index where this sequence contains a given sequence as a slice.

Note: may not terminate for infinite-sized collections.

Value parameters:

from: the start index
that: the sequence to test

Returns:

the first index >= from such that the elements of this sequence starting at this index match the elements of sequence that, or -1 of no such subsequence exists.

Inherited from:

Source:

@deprecatedOverriding("Override indexWhere(p, from) instead - indexWhere(p) calls indexWhere(p, 0)", "2.13.0")

Finds index of the first element satisfying some predicate.

Note: may not terminate for infinite-sized collections.

Value parameters:

p: the predicate used to test elements.

Returns:

the index >= 0 of the first element of this sequence that satisfies the predicate p, or -1, if none exists.

Inherited from:

Source:

Finds index of the first element satisfying some predicate after or at some start index.

Note: may not terminate for infinite-sized collections.

Value parameters:

from: the start index
p: the predicate used to test elements.

Returns:

the index >= from of the first element of this sequence that satisfies the predicate p, or -1, if none exists.

Definition Classes

Inherited from:

Source:

Produces the range of all indices of this sequence.

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

Returns:: a Range value from 0 to one less than the length of this sequence.
Inherited from:: SeqOps
Source:: Seq.scala

The initial part of the collection without its last element.

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

Inherited from:: IterableOps
Source:: Iterable.scala

Iterates over the inits of this iterable collection.

Iterates over the inits of this iterable collection. The first value will be this iterable collection and the final one will be an empty iterable collection, with the intervening values the results of successive applications of init.

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

Returns:: an iterator over all the inits of this iterable collection
Example:: List(1,2,3).inits = Iterator(List(1,2,3), List(1,2), List(1), Nil)
Inherited from:: IterableOps
Source:: Iterable.scala

Computes the multiset intersection between this sequence and another sequence.

Value parameters:

that: the sequence of elements to intersect with.

Returns:

a new sequence which contains all elements of this sequence which also appear in that. If an element value x appears n times in that, then the first n occurrences of x will be retained in the result, but any following occurrences will be omitted.

Definition Classes

Inherited from:

Source:

Tests whether this sequence contains given index.

The implementations of methods apply and isDefinedAt turn a Seq[A] into a PartialFunction[Int, A].

Value parameters:

idx: the index to test

Returns:

true if this sequence contains an element at position idx, false otherwise.

Definition Classes

Inherited from:

Source:

Tests whether this iterable collection can be repeatedly traversed.

Tests whether this iterable collection can be repeatedly traversed. Always true for Iterables and false for Iterators unless overridden.

Returns:: true if it is repeatedly traversable, false otherwise.
Definition Classes: IterableOps -> IterableOnceOps
Inherited from:: IterableOps
Source:: Iterable.scala

Iterator can be used only once

Definition Classes: StrictOptimizedLinearSeqOps -> LinearSeqOps -> IterableOnce
Inherited from:: StrictOptimizedLinearSeqOps
Source:: LinearSeq.scala

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

Finds index of last occurrence of some value in this sequence before or at a given end index.

Note: will not terminate for infinite-sized collections.

Type parameters:

B: the type of the element elem.

Value parameters:

elem: the element value to search for.
end: the end index.

Returns:

the index <= end of the last element of this sequence that is equal (as determined by ==) to elem, or -1, if none exists.

Inherited from:

Source:

@deprecatedOverriding("Override lastIndexOfSlice(that, end) instead - lastIndexOfSlice(that) calls lastIndexOfSlice(that, Int.MaxValue)", "2.13.0")

Finds last index where this sequence contains a given sequence as a slice.

Note: will not terminate for infinite-sized collections.

Value parameters:

that: the sequence to test

Returns:

the last index such that the elements of this sequence starting at this index match the elements of sequence that, or -1 of no such subsequence exists.

Inherited from:

Source:

Finds last index before or at a given end index where this sequence contains a given sequence as a slice.

Note: will not terminate for infinite-sized collections.

Value parameters:

end: the end index
that: the sequence to test

Returns:

the last index <= end such that the elements of this sequence starting at this index match the elements of sequence that, or -1 of no such subsequence exists.

Inherited from:

Source:

@deprecatedOverriding("Override lastIndexWhere(p, end) instead - lastIndexWhere(p) calls lastIndexWhere(p, Int.MaxValue)", "2.13.0")

Finds index of last element satisfying some predicate.

Note: will not terminate for infinite-sized collections.

Value parameters:

p: the predicate used to test elements.

Returns:

the index of the last element of this sequence that satisfies the predicate p, or -1, if none exists.

Inherited from:

Source:

Finds index of last element satisfying some predicate before or at given end index.

Note: will not terminate for infinite-sized collections.

Value parameters:

p: the predicate used to test elements.

Returns:

the index <= end of the last element of this sequence that satisfies the predicate p, or -1, if none exists.

Definition Classes

Inherited from:

Source:

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.
Inherited from:: IterableOps
Source:: Iterable.scala

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

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

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

Type parameters:

B: the type of the second element in each eventual pair

Value parameters:

that: the iterable providing the second element of each eventual pair

Returns:

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

Inherited from:

Iterable

Source:

Compares the length of this sequence to the size of another Iterable.

Value parameters:

that: the Iterable whose size is compared with this sequence's length.

Returns:

A value x where

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

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

Definition Classes

Inherited from:

Source:

Returns a value class containing operations for comparing the length of this sequence to a test value.

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

this.lengthIs < len     // this.lengthCompare(len) < 0
this.lengthIs <= len    // this.lengthCompare(len) <= 0
this.lengthIs == len    // this.lengthCompare(len) == 0
this.lengthIs != len    // this.lengthCompare(len) != 0
this.lengthIs >= len    // this.lengthCompare(len) >= 0
this.lengthIs > len     // this.lengthCompare(len) > 0

Inherited from:: SeqOps
Source:: Seq.scala

Turns this partial function into a plain function returning an Option result.

Returns:: a function that takes an argument x to Some(this(x)) if this is defined for x, and to None otherwise.
See also:: Function.unlift
Inherited from:: PartialFunction
Source:: PartialFunction.scala

Finds the largest element.

Note: will not terminate for infinite-sized collections.

Type parameters:

B: The type over which the ordering is defined.

Value parameters:

ord: An ordering to be used for comparing elements.

Returns:

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

Throws:

UnsupportedOperationException: if this collection is empty.

Inherited from:

Source:

Finds the first element which yields the largest value measured by function f.

Note: will not terminate for infinite-sized collections.

Type parameters:

B: The result type of the function f.

Value parameters:

cmp: An ordering to be used for comparing elements.
f: The measuring function.

Returns:

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

Throws:

UnsupportedOperationException: if this collection is empty.

Inherited from:

Source:

Finds the first element which yields the largest value measured by function f.

Note: will not terminate for infinite-sized collections.

Type parameters:

B: The result type of the function f.

Value parameters:

cmp: An ordering to be used for comparing elements.
f: The measuring function.

Returns:

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

Inherited from:

Source:

Finds the largest element.

Note: will not terminate for infinite-sized collections.

Type parameters:

B: The type over which the ordering is defined.

Value parameters:

ord: An ordering to be used for comparing elements.

Returns:

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

Inherited from:

Source:

Finds the smallest element.

Note: will not terminate for infinite-sized collections.

Type parameters:

B: The type over which the ordering is defined.

Value parameters:

ord: An ordering to be used for comparing elements.

Returns:

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

Throws:

UnsupportedOperationException: if this collection is empty.

Inherited from:

Source:

Finds the first element which yields the smallest value measured by function f.

Note: will not terminate for infinite-sized collections.

Type parameters:

B: The result type of the function f.

Value parameters:

cmp: An ordering to be used for comparing elements.
f: The measuring function.

Returns:

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

Throws:

UnsupportedOperationException: if this collection is empty.

Inherited from:

Source:

Finds the first element which yields the smallest value measured by function f.

Note: will not terminate for infinite-sized collections.

Type parameters:

B: The result type of the function f.

Value parameters:

cmp: An ordering to be used for comparing elements.
f: The measuring function.

Returns:

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

Inherited from:

Source:

Finds the smallest element.

Note: will not terminate for infinite-sized collections.

Type parameters:

B: The type over which the ordering is defined.

Value parameters:

ord: An ordering to be used for comparing elements.

Returns:

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

Inherited from:

Source:

Displays all elements of this collection in a string.

Delegates to addString, which can be overridden.

Returns:: a string representation of this collection. In the resulting string the string representations (w.r.t. the method toString) of all elements of this collection follow each other without any separator string.
Inherited from:: IterableOnceOps
Source:: IterableOnce.scala

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

Delegates to addString, which can be overridden.

Value parameters:

sep: the separator string.

Returns:

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

Example:

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

Inherited from:

Source:

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

Delegates to addString, which can be overridden.

Value parameters:

end: the ending string.
sep: the separator string.
start: the starting string.

Returns:

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

Example:

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

Inherited from:

Source:

Returns:: a strict builder for the same collection type. Note that in the case of lazy collections (e.g. scala.collection.View or scala.collection.immutable.LazyList), it is possible to implement this method but the resulting Builder will break laziness. As a consequence, operations should preferably be implemented with fromSpecific instead of this method.
Note:: When implementing a custom collection type and refining C to the new type, this method needs to be overridden (the compiler will issue an error otherwise). In the common case where C =:= CC[A], this can be done by mixing in the scala.collection.IterableFactoryDefaults trait, which implements the method using iterableFactory.
As witnessed by the @uncheckedVariance annotation, using this method might be unsound. However, as long as the returned builder is only fed with A values taken from this instance, it is safe.
Inherited from:: IterableFactoryDefaults
Source:: Iterable.scala

@deprecatedOverriding("nonEmpty is defined as !isEmpty; override isEmpty instead", "2.13.0")

Tests whether the collection is not empty.

Returns:: true if the collection contains at least one element, false otherwise.
Inherited from:: IterableOnceOps
Source:: IterableOnce.scala

Composes this partial function with a fallback partial function which gets applied where this partial function is not defined.

Type parameters:

A1: the argument type of the fallback function
B1: the result type of the fallback function

Value parameters:

that: the fallback function

Returns:

a partial function which has as domain the union of the domains of this partial function and that. The resulting partial function takes x to this(x) where this is defined, and to that(x) where it is not.

Inherited from:

Source:

A copy of this sequence with an element value appended until a given target length is reached.

Type parameters:

B: the element type of the returned sequence.

Value parameters:

elem: the padding value
len: the target length

Returns:

a new sequence consisting of all elements of this sequence followed by the minimal number of occurrences of elem so that the resulting collection has a length of at least len.

Definition Classes

Inherited from:

Source:

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

Example:

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

Type parameters:

A1: the element type of the first resulting collection
A2: the element type of the second resulting collection

Value parameters:

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

Returns:

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

Definition Classes

Inherited from:

Source:

Produces a new sequence where a slice of elements in this sequence is replaced by another sequence.

Patching at negative indices is the same as patching starting at 0. Patching at indices at or larger than the length of the original sequence appends the patch to the end. If more values are replaced than actually exist, the excess is ignored.

Type parameters:

B: the element type of the returned sequence.

Value parameters:

from: the index of the first replaced element
other: the replacement sequence
replaced: the number of elements to drop in the original sequence

Returns:

a new sequence consisting of all elements of this sequence except that replaced elements starting from from are replaced by all the elements of other.

Definition Classes

Inherited from:

Source:

Iterates over distinct permutations.

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

Returns:: An Iterator which traverses the distinct permutations of this sequence.
Example:: "abb".permutations = Iterator(abb, bab, bba)
Inherited from:: SeqOps
Source:: Seq.scala

Multiplies up the elements of this collection.

Note: will not terminate for infinite-sized collections.

Type parameters:

B: the result type of the * operator.

Value parameters:

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

Returns:

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

Inherited from:

Source:

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

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

Type parameters:

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

Value parameters:

op: A binary operator that must be associative.

Returns:

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

Throws:

UnsupportedOperationException: if this collection is empty.

Inherited from:

Source:

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

Note: will not terminate for infinite-sized collections.

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

Type parameters:

B: the result type of the binary operator.

Value parameters:

op: the binary operator.

Returns:

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

Throws:

UnsupportedOperationException: if this collection is empty.

Inherited from:

Source:

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

Note: will not terminate for infinite-sized collections.

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

Type parameters:

B: the result type of the binary operator.

Value parameters:

op: the binary operator.

Returns:

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

Inherited from:

Source:

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

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

Type parameters:

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

Value parameters:

op: A binary operator that must be associative.

Returns:

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

Inherited from:

Source:

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

Note: will not terminate for infinite-sized collections.

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

Type parameters:

B: the result type of the binary operator.

Value parameters:

op: the binary operator.

Returns:

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

Throws:

UnsupportedOperationException: if this collection is empty.

Inherited from:

Source:

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

Note: will not terminate for infinite-sized collections.

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

Type parameters:

B: the result type of the binary operator.

Value parameters:

op: the binary operator.

Returns:

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

Inherited from:

Source:

An iterator yielding elements in reversed order.

Note: will not terminate for infinite-sized collections.

Note: xs.reverseIterator is the same as xs.reverse.iterator but might be more efficient.

Returns:: an iterator yielding the elements of this sequence in reversed order
Inherited from:: SeqOps
Source:: Seq.scala

Inherited from:: IterableOnceOps
Source:: IterableOnce.scala

Composes this partial function with an action function which gets applied to results of this partial function.

Composes this partial function with an action function which gets applied to results of this partial function. The action function is invoked only for its side effects; its result is ignored.

Note that expression pf.runWith(action)(x) is equivalent to

if(pf isDefinedAt x) { action(pf(x)); true } else false

except that runWith is implemented via applyOrElse and thus potentially more efficient. Using runWith avoids double evaluation of pattern matchers and guards for partial function literals.

Value parameters:

action: the action function

Returns:

a function which maps arguments x to isDefinedAt(x). The resulting function runs action(this(x)) where this is defined.

See also:

applyOrElse.

Inherited from:

Source:

Are the elements of this collection the same (and in the same order) as those of that?

Definition Classes: LinearSeqOps -> SeqOps
Inherited from:: LinearSeqOps
Source:: LinearSeq.scala

Computes a prefix scan of the elements of the collection.

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

Type parameters:

B: element type of the resulting collection

Value parameters:

op: the associative operator for the scan
z: neutral element for the operator op

Returns:

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

Inherited from:

Source:

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

Note: will not terminate for infinite-sized collections.

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

Type parameters:

B: the type of the elements in the resulting collection

Value parameters:

op: the binary operator applied to the intermediate result and the element
z: the initial value

Returns:

collection with intermediate results

Definition Classes

StrictOptimizedIterableOps -> IterableOps -> IterableOnceOps

Inherited from:

Source:

Produces a collection containing cumulative results of applying the operator going right to left.

Produces a collection containing cumulative results of applying the operator going right to left. The head of the collection is the last cumulative result.

Note: will not terminate for infinite-sized collections.

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

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

Example:

List(1, 2, 3, 4).scanRight(0)(_ + _) == List(10, 9, 7, 4, 0)

Type parameters:

B: the type of the elements in the resulting collection

Value parameters:

op: the binary operator applied to the intermediate result and the element
z: the initial value

Returns:

collection with intermediate results

Inherited from:

Source:

scala.collection.IndexedSeq

Search within an interval in this sorted sequence for a specific element.

Search within an interval in this sorted sequence for a specific element. If this sequence is an IndexedSeq, a binary search is used. Otherwise, a linear search is used.

The sequence should be sorted with the same Ordering before calling; otherwise, the results are undefined.

Value parameters:

elem: the element to find.
from: the index where the search starts.
ord: the ordering to be used to compare elements.
to: the index following where the search ends.

Returns:

a Found value containing the index corresponding to the element in the sequence, or the InsertionPoint where the element would be inserted if the element is not in the sequence.

See also:

scala.math.Ordering

scala.collection.SeqOps, method sorted

Note:

if to <= from, the search space is empty, and an InsertionPoint at from is returned

Inherited from:

Source:

scala.collection.IndexedSeq

Search this sorted sequence for a specific element.

Search this sorted sequence for a specific element. If the sequence is an IndexedSeq, a binary search is used. Otherwise, a linear search is used.

The sequence should be sorted with the same Ordering before calling; otherwise, the results are undefined.

Value parameters:

elem: the element to find.
ord: the ordering to be used to compare elements.

Returns:

a Found value containing the index corresponding to the element in the sequence, or the InsertionPoint where the element would be inserted if the element is not in the sequence.

See also:

scala.math.Ordering

scala.collection.SeqOps, method sorted

Inherited from:

Source:

Computes the length of the longest segment that starts from some index and whose elements all satisfy some predicate.

Note: may not terminate for infinite-sized collections.

Value parameters:

from: the index where the search starts.
p: the predicate used to test elements.

Returns:

the length of the longest segment of this sequence starting from index from such that every element of the segment satisfies the predicate p.

Definition Classes

Inherited from:

Source:

Computes the length of the longest segment that starts from the first element and whose elements all satisfy some predicate.

Note: may not terminate for infinite-sized collections.

Value parameters:

p: the predicate used to test elements.

Returns:

the length of the longest segment of this sequence that starts from the first element such that every element of the segment satisfies the predicate p.

Inherited from:

Source:

The size of this sequence.

Note: will not terminate for infinite-sized collections.

Returns:: the number of elements in this sequence.
Definition Classes: SeqOps -> IterableOnceOps
Inherited from:: SeqOps
Source:: Seq.scala

Compares the size of this sequence to the size of another Iterable.

Value parameters:

that: the Iterable whose size is compared with this sequence's size.

Returns:

A value x where

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

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

Definition Classes

SeqOps -> IterableOps

Inherited from:

Source:

Compares the size of this sequence to a test value.

Value parameters:

otherSize: the test value that gets compared with the size.

Returns:

A value x where

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

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

See also:

sizeIs

Definition Classes

SeqOps -> IterableOps

Inherited from:

Source:

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

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

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

Inherited from:: IterableOps
Source:: Iterable.scala

Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.)

The returned iterator will be empty when called on an empty collection. The last element the iterator produces may be smaller than the window size when the original collection isn't exhausted by the window before it and its last element isn't skipped by the step before it.

Value parameters:

size: the number of elements per group
step: the distance between the first elements of successive groups

Returns:

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

See also:

scala.collection.Iterator, method sliding

Example:

List(1, 2, 3, 4, 5).sliding(2, 2) = Iterator(List(1, 2), List(3, 4), List(5))

List(1, 2, 3, 4, 5, 6).sliding(2, 3) = Iterator(List(1, 2), List(4, 5))

Inherited from:

Source:

Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.)

An empty collection returns an empty iterator, and a non-empty collection containing fewer elements than the window size returns an iterator that will produce the original collection as its only element.

Value parameters:

size: the number of elements per group

Returns:

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

See also:

scala.collection.Iterator, method sliding

Example:

List().sliding(2) = empty iterator

List(1).sliding(2) = Iterator(List(1))

List(1, 2).sliding(2) = Iterator(List(1, 2))

List(1, 2, 3).sliding(2) = Iterator(List(1, 2), List(2, 3))

Inherited from:

Source:

Sorts this sequence according to the Ordering which results from transforming an implicitly given Ordering with a transformation function.

Note: will not terminate for infinite-sized collections.

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

The sort is stable. That is, elements that are equal (as determined by ord.compare) appear in the same order in the sorted sequence as in the original.

Type parameters:

B: the target type of the transformation f, and the type where the ordering ord is defined.

Value parameters:

f: the transformation function mapping elements to some other domain B.
ord: the ordering assumed on domain B.

Returns:

a sequence consisting of the elements of this sequence sorted according to the ordering where x < y if ord.lt(f(x), f(y)).

See also:

scala.math.Ordering

Example:

val words = "The quick brown fox jumped over the lazy dog".split(' ')
// this works because scala.Ordering will implicitly provide an Ordering[Tuple2[Int, Char]]
words.sortBy(x => (x.length, x.head))
res0: Array[String] = Array(The, dog, fox, the, lazy, over, brown, quick, jumped)

Inherited from:

Source:

Sorts this sequence according to a comparison function.

Note: will not terminate for infinite-sized collections.

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

The sort is stable. That is, elements that are equal (as determined by lt) appear in the same order in the sorted sequence as in the original.

Value parameters:

lt: the comparison function which tests whether its first argument precedes its second argument in the desired ordering.

Returns:

a sequence consisting of the elements of this sequence sorted according to the comparison function lt.

Example:

List("Steve", "Tom", "John", "Bob").sortWith(_.compareTo(_) < 0) =
List("Bob", "John", "Steve", "Tom")

Inherited from:

Source:

Sorts this sequence according to an Ordering.

The sort is stable. That is, elements that are equal (as determined by ord.compare) appear in the same order in the sorted sequence as in the original.

Value parameters:

ord: the ordering to be used to compare elements.

Returns:

a sequence consisting of the elements of this sequence sorted according to the ordering ord.

See also:

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

Definition Classes

Inherited from:

Source:

Tests whether this sequence contains the given sequence at a given index.

Note: If the both the receiver object this and the argument that are infinite sequences this method may not terminate.

Value parameters:

offset: the index where the sequence is searched.
that: the sequence to test

Returns:

true if the sequence that is contained in this sequence at index offset, otherwise false.

Inherited from:

Source:

Returns a scala.collection.Stepper for the elements of this collection.

The Stepper enables creating a Java stream to operate on the collection, see scala.jdk.StreamConverters. For collections holding primitive values, the Stepper can be used as an iterator which doesn't box the elements.

The implicit scala.collection.StepperShape parameter defines the resulting Stepper type according to the element type of this collection.

For collections of Int, Short, Byte or Char, an scala.collection.IntStepper is returned
For collections of Double or Float, a scala.collection.DoubleStepper is returned
For collections of Long a scala.collection.LongStepper is returned
For any other element type, an scala.collection.AnyStepper is returned

Note that this method is overridden in subclasses and the return type is refined to S with EfficientSplit, for example scala.collection.IndexedSeqOps.stepper. For Steppers marked with scala.collection.Stepper.EfficientSplit, the converters in scala.jdk.StreamConverters allow creating parallel streams, whereas bare Steppers can be converted only to sequential streams.

Inherited from:: IterableOnce
Source:: IterableOnce.scala

Sums up the elements of this collection.

Note: will not terminate for infinite-sized collections.

Type parameters:

B: the result type of the + operator.

Value parameters:

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

Returns:

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

Inherited from:

Source:

The rest of the collection without its first element.

Inherited from:: IterableOps
Source:: Iterable.scala

Iterates over the tails of this sequence.

Iterates over the tails of this sequence. The first value will be this sequence and the final one will be an empty sequence, with the intervening values the results of successive applications of tail.

Returns:: an iterator over all the tails of this sequence
Example:: List(1,2,3).tails = Iterator(List(1,2,3), List(2,3), List(3), Nil)
Definition Classes: LinearSeqOps -> IterableOps
Inherited from:: LinearSeqOps
Source:: LinearSeq.scala

Applies a side-effecting function to each element in this collection.

Applies a side-effecting function to each element in this collection. Strict collections will apply f to their elements immediately, while lazy collections like Views and LazyLists will only apply f on each element if and when that element is evaluated, and each time that element is evaluated.

Type parameters:

U: the return type of f

Value parameters:

f: a function to apply to each element in this iterable collection

Returns:

The same logical collection as this

Definition Classes

StrictOptimizedIterableOps -> IterableOps -> IterableOnceOps

Inherited from:

Source:

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

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

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

Inherited from:: IterableOnceOps
Source:: IterableOnce.scala

Convert collection to array.

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

Inherited from:: IterableOnceOps
Source:: IterableOnce.scala

Inherited from:: IterableOnceOps
Source:: IterableOnce.scala

Inherited from:: IterableOnceOps
Source:: IterableOnce.scala

Inherited from:: IterableOnceOps
Source:: IterableOnce.scala

Returns:: This collection as a Seq[A]. This is equivalent to to(Seq) but might be faster.
Definition Classes: Seq -> IterableOnceOps
Inherited from:: Seq
Source:: Seq.scala

Inherited from:: IterableOnceOps
Source:: IterableOnce.scala

Returns a string representation of the object.

The default representation is platform dependent.

Returns:: a string representation of the object.
Definition Classes: Seq -> Function1 -> Iterable -> Any
Inherited from:: Seq
Source:: Seq.scala

Inherited from:: IterableOnceOps
Source:: IterableOnce.scala

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

The resulting collection's type will be guided by the static type of iterable collection. For example:

val xs = List(
           Set(1, 2, 3),
           Set(4, 5, 6)).transpose
// xs == List(
//         List(1, 4),
//         List(2, 5),
//         List(3, 6))

val ys = Vector(
           List(1, 2, 3),
           List(4, 5, 6)).transpose
// ys == Vector(
//         Vector(1, 4),
//         Vector(2, 5),
//         Vector(3, 6))

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

Type parameters:

B: the type of the elements of each iterable collection.

Value parameters:

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

Returns:

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

Throws:

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

Inherited from:

Source:

Tries to extract a B from an A in a pattern matching expression.

Inherited from:: PartialFunction
Source:: PartialFunction.scala

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))

Type parameters:

A1: the type of the first half of the element pairs
A2: the type of the second half of the element pairs

Value parameters:

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.

Definition Classes

Inherited from:

Source:

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))

Type parameters:

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

Value parameters:

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.

Definition Classes

Inherited from:

Source:

A view over the elements of this collection.

Definition Classes: SeqOps -> IterableOps
Inherited from:: SeqOps
Source:: Seq.scala

Creates a non-strict filter of this iterable collection.

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

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

Value parameters:

p: the predicate used to test elements.

Returns:

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

Inherited from:

Source:

Returns a iterable collection formed from this iterable collection and another iterable collection by combining corresponding elements in pairs.

Returns a iterable collection formed from this iterable collection and another iterable collection by combining corresponding elements in pairs. If one of the two collections is longer than the other, its remaining elements are ignored.

Type parameters:

B: the type of the second half of the returned pairs

Value parameters:

that: The iterable providing the second half of each result pair

Returns:

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

Definition Classes

Inherited from:

Source:

Returns a iterable collection formed from this iterable collection and another iterable collection by combining corresponding elements in pairs.

Returns a iterable collection formed from this iterable collection and another iterable collection by combining corresponding elements in pairs. If one of the two collections is shorter than the other, placeholder elements are used to extend the shorter collection to the length of the longer.

Value parameters:

that: the iterable providing the second half of each result pair
thatElem: the element to be used to fill up the result if that is shorter than this iterable collection.
thisElem: the element to be used to fill up the result if this iterable collection is shorter than that.

Returns:

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

Inherited from:

Source:

Zips this iterable collection with its indices.

Returns:: A new iterable collection containing pairs consisting of all elements of this iterable collection paired with their index. Indices start at 0.
Example:: List("a", "b", "c").zipWithIndex == List(("a", 0), ("b", 1), ("c", 2))
Definition Classes: StrictOptimizedIterableOps -> IterableOps -> IterableOnceOps
Inherited from:: StrictOptimizedIterableOps
Source:: StrictOptimizedIterableOps.scala

Deprecated and Inherited methods

@deprecated("Use foldLeft instead of /:", "2.13.0") @inline

Deprecated
Inherited from:: IterableOnceOps
Source:: IterableOnce.scala

@deprecated("Use foldRight instead of :\\", "2.13.0") @inline

Deprecated
Inherited from:: IterableOnceOps
Source:: IterableOnce.scala

@deprecated("`aggregate` is not relevant for sequential collections. Use `foldLeft(z)(seqop)` instead.", "2.13.0")

Deprecated
Inherited from:: IterableOnceOps
Source:: IterableOnce.scala

@deprecated("Use iterableFactory instead", "2.13.0") @deprecatedOverriding("Use iterableFactory instead", "2.13.0") @inline

Deprecated
Inherited from:: IterableOps
Source:: Iterable.scala

@deprecated("Use `dest ++= coll` instead", "2.13.0") @inline

Deprecated
Inherited from:: IterableOnceOps
Source:: IterableOnce.scala

@deprecated("Check .knownSize instead of .hasDefiniteSize for more actionable information (see scaladoc for details)", "2.13.0")

Tests whether this collection is known to have a finite size.

Tests whether this collection is known to have a finite size. All strict collections are known to have finite size. For a non-strict collection such as Stream, the predicate returns true if all elements have been computed. It returns false if the stream is not yet evaluated to the end. Non-empty Iterators usually return false even if they were created from a collection with a known finite size.

Note: many collection methods will not work on collections of infinite sizes. The typical failure mode is an infinite loop. These methods always attempt a traversal without checking first that hasDefiniteSize returns true. However, checking hasDefiniteSize can provide an assurance that size is well-defined and non-termination is not a concern.

Returns:: true if this collection is known to have finite size, false otherwise.
See also:: method knownSize for a more useful alternative
Deprecated: This method is deprecated in 2.13 because it does not provide any actionable information. As noted above, even the collection library itself does not use it. When there is no guarantee that a collection is finite, it is generally best to attempt a computation anyway and document that it will not terminate for infinite collections rather than backing out because this would prevent performing the computation on collections that are in fact finite even though hasDefiniteSize returns false.
Inherited from:: IterableOnceOps
Source:: IterableOnce.scala

@deprecated("Use segmentLength instead of prefixLength", "2.13.0") @inline

Returns the length of the longest prefix whose elements all satisfy some predicate.

Note: may not terminate for infinite-sized collections.

Value parameters:

p: the predicate used to test elements.

Returns:

the length of the longest prefix of this sequence such that every element of the segment satisfies the predicate p.

Deprecated

Inherited from:

Source:

@deprecated("Use coll instead of repr in a collection implementation, use the collection value itself from the outside", "2.13.0")

Deprecated
Inherited from:: IterableOps
Source:: Iterable.scala

@deprecated("Use .reverseIterator.map(f).to(...) instead of .reverseMap(f)", "2.13.0")

Deprecated
Inherited from:: SeqOps
Source:: Seq.scala

@deprecated("Iterable.seq always returns the iterable itself", "2.13.0")

Deprecated
Inherited from:: Iterable
Source:: Iterable.scala

@deprecated("toIterable is internal and will be made protected; its name is similar to `toList` or `toSeq`, but it doesn\'t copy non-immutable collections", "2.13.7")

Returns:: This collection as an Iterable[A]. No new collection will be built if this is already an Iterable[A].
Deprecated
Inherited from:: Iterable
Source:: Iterable.scala

@deprecated("Use .iterator instead of .toIterator", "2.13.0") @inline

Deprecated
Inherited from:: IterableOnceOps
Source:: IterableOnce.scala

@deprecated("Use .to(LazyList) instead of .toStream", "2.13.0") @inline

Deprecated
Inherited from:: IterableOnceOps
Source:: IterableOnce.scala

@deprecated("toTraversable is internal and will be made protected; its name is similar to `toList` or `toSeq`, but it doesn\'t copy non-immutable collections", "2.13.0")

Converts this iterable collection to an unspecified Iterable.

Converts this iterable collection to an unspecified Iterable. Will return the same collection if this instance is already Iterable.

Returns:: An Iterable containing all elements of this iterable collection.
Deprecated
Inherited from:: IterableOps
Source:: Iterable.scala

@deprecated("Use `concat` instead", "2.13.0") @inline

Produces a new sequence which contains all elements of this sequence and also all elements of a given sequence.

Produces a new sequence which contains all elements of this sequence and also all elements of a given sequence. xs union ys is equivalent to xs ++ ys.

Type parameters:

B: the element type of the returned sequence.

Value parameters:

that: the sequence to add.

Returns:

a new collection which contains all elements of this sequence followed by all elements of that.

Deprecated

Inherited from:

Source: