AnyCollectionType

protocol AnyCollectionType

A protocol for AnyForwardCollection<Element>, AnyBidirectionalCollection<Element>, and AnyRandomAccessCollection<Element>.

This protocol can be considered an implementation detail of the === and !== implementations for these types.

Inheritance CollectionType, Indexable, SequenceType View Protocol Hierarchy →
Associated Types
Generator : GeneratorType = IndexingGenerator<Self>

A type that provides the sequence's iteration interface and encapsulates its iteration state.

By default, a CollectionType satisfies SequenceType by supplying an IndexingGenerator as its associated Generator type.

SubSequence : Indexable, SequenceType = Slice<Self>

A SequenceType that can represent a contiguous subrange of self's elements.

Note: This associated type appears as a requirement in SequenceType, but is restated here with stricter constraints: in a CollectionType, the SubSequence should also be a CollectionType.

Index : ForwardIndexType

A type that represents a valid position in the collection.

Valid indices consist of the position of every element and a "past the end" position that's not valid for use as a subscript.
Import import Swift

Instance Variables

var count: Self.Index.Distance

Returns the number of elements.

Complexity: O(1) if Index conforms to RandomAccessIndexType; O(N) otherwise.

Declaration

var count: Self.Index.Distance { get }

Declared In

CollectionType
var first: Self.Generator.Element?

Returns the first element of self, or nil if self is empty.

Declaration

var first: Self.Generator.Element? { get }

Declared In

CollectionType
var isEmpty: Bool

Returns true iff self is empty.

Declaration

var isEmpty: Bool { get }

Declared In

CollectionType
var endIndex: Self.Index Required

The collection's "past the end" position.

endIndex is not a valid argument to subscript, and is always reachable from startIndex by zero or more applications of successor().

Complexity: O(1)

Declaration

var endIndex: Self.Index { get }

Declared In

Indexable
var startIndex: Self.Index Required

The position of the first element in a non-empty collection.

In an empty collection, startIndex == endIndex.

Complexity: O(1)

Declaration

var startIndex: Self.Index { get }

Declared In

Indexable

Subscripts

subscript(_: Range<Self.Index>) Required

Returns a collection representing a contiguous sub-range of self's elements.

Complexity: O(1)

Declaration

subscript(bounds: Range<Self.Index>) -> Self.SubSequence { get }

Declared In

CollectionType
subscript(_: Self.Index) Required

Returns the element at the given position.

Declaration

subscript(position: Self.Index) -> Self.Generator.Element { get }

Declared In

CollectionType, Indexable

Instance Methods

func dropFirst(_:)

Returns a subsequence containing all but the first n elements.

Requires: n >= 0 Complexity: O(n)

Declaration

func dropFirst(n: Int) -> Self.SubSequence

Declared In

SequenceType
func dropLast(_:)

Returns a subsequence containing all but the last n elements.

Requires: self is a finite sequence. Requires: n >= 0 Complexity: O(self.count)

Declaration

func dropLast(n: Int) -> Self.SubSequence

Declared In

SequenceType
func filter(_:)

Returns an Array containing the elements of self, in order, that satisfy the predicate includeElement.

Declaration

func filter(@noescape includeElement: (Self.Generator.Element) throws -> Bool) rethrows -> [Self.Generator.Element]

Declared In

SequenceType
func forEach(_:)

Call body on each element in self in the same order as a for-in loop.

sequence.forEach {
  // body code
}

is similar to:

for element in sequence {
  // body code
}

Note: You cannot use the break or continue statement to exit the current call of the body closure or skip subsequent calls. Note: Using the return statement in the body closure will only exit from the current call to body, not any outer scope, and won't skip subsequent calls.

Complexity: O(self.count)

Declaration

func forEach(@noescape body: (Self.Generator.Element) throws -> Void) rethrows

Declared In

SequenceType
func generate() Required

Declaration

func generate() -> Self.Generator

Declared In

CollectionType, SequenceType
func map(_:)

Returns an Array containing the results of mapping transform over self.

Complexity: O(N).

Declaration

func map<T>(@noescape transform: (Self.Generator.Element) throws -> T) rethrows -> [T]

Declared In

SequenceType
func prefix(_:)

Returns a subsequence, up to maxLength in length, containing the initial elements.

If maxLength exceeds self.count, the result contains all the elements of self.

Requires: maxLength >= 0

Declaration

func prefix(maxLength: Int) -> Self.SubSequence

Declared In

SequenceType
func prefixThrough(_:)

Returns prefixUpTo(position.successor())

Complexity: O(1)

Declaration

func prefixThrough(position: Self.Index) -> Self.SubSequence

Declared In

CollectionType
func prefixUpTo(_:)

Returns self[startIndex..<end]

Complexity: O(1)

Declaration

func prefixUpTo(end: Self.Index) -> Self.SubSequence

Declared In

CollectionType
func split(_:allowEmptySlices:isSeparator:)

Returns the maximal SubSequences of self, in order, that don't contain elements satisfying the predicate isSeparator.

maxSplit: The maximum number of SubSequences to return, minus 1. If maxSplit + 1 SubSequences are returned, the last one is a suffix of self containing the remaining elements. The default value is Int.max.

allowEmptySubsequences: If true, an empty SubSequence is produced in the result for each pair of consecutive elements satisfying isSeparator. The default value is false.

Requires: maxSplit >= 0

Declaration

func split(maxSplit: Int, allowEmptySlices: Bool, @noescape isSeparator: (Self.Generator.Element) throws -> Bool) rethrows -> [Self.SubSequence]

Declared In

SequenceType
func suffix(_:)

Returns a slice, up to maxLength in length, containing the final elements of s.

If maxLength exceeds s.count, the result contains all the elements of s.

Requires: self is a finite sequence. Requires: maxLength >= 0

Declaration

func suffix(maxLength: Int) -> Self.SubSequence

Declared In

SequenceType
func suffixFrom(_:)

Returns self[start..<endIndex]

Complexity: O(1)

Declaration

func suffixFrom(start: Self.Index) -> Self.SubSequence

Declared In

CollectionType
func underestimateCount()

Returns a value less than or equal to the number of elements in self, nondestructively.

Complexity: O(N).

Declaration

func underestimateCount() -> Int

Declared In

SequenceType

Default Implementations

var count: Self.Index.Distance

Returns the number of elements.

Complexity: O(1) if Index conforms to RandomAccessIndexType; O(N) otherwise.

Declaration

var count: Self.Index.Distance { get }

Declared In

CollectionType
var first: Self.Generator.Element?

Returns the first element of self, or nil if self is empty.

Complexity: O(1)

Declaration

var first: Self.Generator.Element? { get }

Declared In

CollectionType
var indices: Range<Self.Index>

Returns the range of valid index values.

The result's endIndex is the same as that of self. Because Range is half-open, iterating the values of the result produces all valid subscript arguments for self, omitting its endIndex.

Declaration

var indices: Range<Self.Index> { get }

Declared In

CollectionType
var isEmpty: Bool

Returns true iff self is empty.

Complexity: O(1)

Declaration

var isEmpty: Bool { get }

Declared In

CollectionType
var lazy: LazyCollection<Self>

A collection with contents identical to self, but on which normally-eager operations such as map and filter are implemented lazily.

See Also: LazySequenceType, LazyCollectionType.

Declaration

var lazy: LazyCollection<Self> { get }

Declared In

CollectionType
func contains(_:)

Returns true iff an element in self satisfies predicate.

Declaration

func contains(@noescape predicate: (Self.Generator.Element) throws -> Bool) rethrows -> Bool

Declared In

SequenceType
func dropFirst()

Returns a subsequence containing all but the first element.

Complexity: O(1)

Declaration

func dropFirst() -> Self.SubSequence

Declared In

SequenceType
func dropFirst(_:)

Returns a subsequence containing all but the first n elements.

Requires: n >= 0 Complexity: O(n)

Declaration

func dropFirst(n: Int) -> Self.SubSequence

Declared In

CollectionType
func dropLast()

Returns a subsequence containing all but the last element.

Requires: self is a finite sequence. Complexity: O(self.count)

Declaration

func dropLast() -> Self.SubSequence

Declared In

SequenceType
func dropLast(_:)

Returns a subsequence containing all but the last n elements.

Requires: n >= 0 Complexity: O(self.count)

Declaration

func dropLast(n: Int) -> Self.SubSequence

Declared In

CollectionType
func elementsEqual(_:isEquivalent:)

Returns true iff self and other contain equivalent elements, using isEquivalent as the equivalence test.

Requires: isEquivalent is an equivalence relation.

Declaration

func elementsEqual<OtherSequence : SequenceType where OtherSequence.Generator.Element == Generator.Element>(other: OtherSequence, @noescape isEquivalent: (Self.Generator.Element, Self.Generator.Element) throws -> Bool) rethrows -> Bool

Declared In

SequenceType
func enumerate()

Returns a lazy SequenceType containing pairs (n, x), where ns are consecutive Ints starting at zero, and xs are the elements of base:

> for (n, c) in "Swift".characters.enumerate() {
    print("\(n): '\(c)'")
  }
0: 'S'
1: 'w'
2: 'i'
3: 'f'
4: 't'

Declaration

func enumerate() -> EnumerateSequence<Self>

Declared In

SequenceType
func filter(_:)

Returns an Array containing the elements of self, in order, that satisfy the predicate includeElement.

Declaration

func filter(@noescape includeElement: (Self.Generator.Element) throws -> Bool) rethrows -> [Self.Generator.Element]

Declared In

SequenceType
func flatMap<T>(_: (Self.Generator.Element) throws -> T?)

Returns an Array containing the non-nil results of mapping transform over self.

Complexity: O(M + N), where M is the length of self and N is the length of the result.

Declaration

func flatMap<T>(@noescape transform: (Self.Generator.Element) throws -> T?) rethrows -> [T]

Declared In

SequenceType
func flatMap<S : SequenceType>(_: (Self.Generator.Element) throws -> S)

Returns an Array containing the concatenated results of mapping transform over self.

s.flatMap(transform)

is equivalent to

Array(s.map(transform).flatten())

Complexity: O(M + N), where M is the length of self and N is the length of the result.

Declaration

func flatMap<S : SequenceType>(transform: (Self.Generator.Element) throws -> S) rethrows -> [S.Generator.Element]

Declared In

SequenceType
func forEach(_:)

Call body on each element in self in the same order as a for-in loop.

sequence.forEach {
  // body code
}

is similar to:

for element in sequence {
  // body code
}

Note: You cannot use the break or continue statement to exit the current call of the body closure or skip subsequent calls. Note: Using the return statement in the body closure will only exit from the current call to body, not any outer scope, and won't skip subsequent calls.

Complexity: O(self.count)

Declaration

func forEach(@noescape body: (Self.Generator.Element) throws -> Void) rethrows

Declared In

SequenceType
func indexOf(_:)

Returns the first index where predicate returns true for the corresponding value, or nil if such value is not found.

Complexity: O(self.count).

Declaration

func indexOf(@noescape predicate: (Self.Generator.Element) throws -> Bool) rethrows -> Self.Index?

Declared In

CollectionType
func lexicographicalCompare(_:isOrderedBefore:)

Returns true iff self precedes other in a lexicographical ("dictionary") ordering, using isOrderedBefore as the comparison between elements.

Note: This method implements the mathematical notion of lexicographical ordering, which has no connection to Unicode. If you are sorting strings to present to the end-user, you should use String APIs that perform localized comparison.

Requires: isOrderedBefore is a strict weak ordering over the elements of self and other.

Declaration

func lexicographicalCompare<OtherSequence : SequenceType where OtherSequence.Generator.Element == Generator.Element>(other: OtherSequence, @noescape isOrderedBefore: (Self.Generator.Element, Self.Generator.Element) throws -> Bool) rethrows -> Bool

Declared In

SequenceType
func map(_:)

Returns an Array containing the results of mapping transform over self.

Complexity: O(N).

Declaration

func map<T>(@noescape transform: (Self.Generator.Element) throws -> T) rethrows -> [T]

Declared In

CollectionType, SequenceType
func maxElement(_:)

Returns the maximum element in self or nil if the sequence is empty.

Complexity: O(elements.count).

Requires: isOrderedBefore is a strict weak ordering over self.

Declaration

func maxElement(@noescape isOrderedBefore: (Self.Generator.Element, Self.Generator.Element) throws -> Bool) rethrows -> Self.Generator.Element?

Declared In

SequenceType
func minElement(_:)

Returns the minimum element in self or nil if the sequence is empty.

Complexity: O(elements.count).

Requires: isOrderedBefore is a strict weak ordering over self.

Declaration

func minElement(@noescape isOrderedBefore: (Self.Generator.Element, Self.Generator.Element) throws -> Bool) rethrows -> Self.Generator.Element?

Declared In

SequenceType
func prefix(_:)

Returns a subsequence, up to maxLength in length, containing the initial elements.

If maxLength exceeds self.count, the result contains all the elements of self.

Requires: maxLength >= 0 Complexity: O(maxLength)

Declaration

func prefix(maxLength: Int) -> Self.SubSequence

Declared In

CollectionType
func prefixThrough(_:)

Returns prefixUpTo(position.successor())

Complexity: O(1)

Declaration

func prefixThrough(position: Self.Index) -> Self.SubSequence

Declared In

CollectionType
func prefixUpTo(_:)

Returns self[startIndex..<end]

Complexity: O(1)

Declaration

func prefixUpTo(end: Self.Index) -> Self.SubSequence

Declared In

CollectionType
func reduce(_:combine:)

Returns the result of repeatedly calling combine with an accumulated value initialized to initial and each element of self, in turn, i.e. return combine(combine(...combine(combine(initial, self[0]), self[1]),...self[count-2]), self[count-1]).

Declaration

func reduce<T>(initial: T, @noescape combine: (T, Self.Generator.Element) throws -> T) rethrows -> T

Declared In

SequenceType
func reverse()

Returns an Array containing the elements of self in reverse order.

Complexity: O(N), where N is the length of self.

Declaration

func reverse() -> [Self.Generator.Element]

Declared In

SequenceType
func sort(_:)

Returns an Array containing the sorted elements of source according to isOrderedBefore.

The sorting algorithm is not stable (can change the relative order of elements for which isOrderedBefore does not establish an order).

Requires: isOrderedBefore is a strict weak ordering over the elements in self.

Declaration

func sort(@noescape isOrderedBefore: (Self.Generator.Element, Self.Generator.Element) -> Bool) -> [Self.Generator.Element]

Declared In

SequenceType
func split(_:allowEmptySlices:isSeparator:)

Returns the maximal SubSequences of self, in order, that don't contain elements satisfying the predicate isSeparator.

maxSplit: The maximum number of SubSequences to return, minus 1. If maxSplit + 1 SubSequences are returned, the last one is a suffix of self containing the remaining elements. The default value is Int.max.

allowEmptySubsequences: If true, an empty SubSequence is produced in the result for each pair of consecutive elements satisfying isSeparator. The default value is false.

Requires: maxSplit >= 0

Declaration

func split(maxSplit: Int = default, allowEmptySlices: Bool = default, @noescape isSeparator: (Self.Generator.Element) throws -> Bool) rethrows -> [Self.SubSequence]

Declared In

CollectionType, SequenceType
func startsWith(_:isEquivalent:)

Returns true iff self begins with elements equivalent to those of other, using isEquivalent as the equivalence test. Returns true if other is empty.

Requires: isEquivalent is an equivalence relation.

Declaration

func startsWith<OtherSequence : SequenceType where OtherSequence.Generator.Element == Generator.Element>(other: OtherSequence, @noescape isEquivalent: (Self.Generator.Element, Self.Generator.Element) throws -> Bool) rethrows -> Bool

Declared In

SequenceType
func suffix(_:)

Returns a slice, up to maxLength in length, containing the final elements of s.

If maxLength exceeds s.count, the result contains all the elements of s.

Requires: maxLength >= 0 Complexity: O(self.count)

Declaration

func suffix(maxLength: Int) -> Self.SubSequence

Declared In

CollectionType, SequenceType
func suffixFrom(_:)

Returns self[start..<endIndex]

Complexity: O(1)

Declaration

func suffixFrom(start: Self.Index) -> Self.SubSequence

Declared In

CollectionType
func underestimateCount()

Returns a value less than or equal to the number of elements in self, nondestructively.

Complexity: O(N).

Declaration

func underestimateCount() -> Int

Declared In

CollectionType, SequenceType

Where Generator == IndexingGenerator

func generate()

Declaration

func generate() -> IndexingGenerator<Self>

Declared In

CollectionType

Where Generator == Self, Self : GeneratorType

func generate()

Returns a generator over the elements of this sequence.

Complexity: O(1).

Declaration

func generate() -> Self

Declared In

SequenceType

Where Generator.Element : CollectionType

func flatten()

A concatenation of the elements of self.

Declaration

func flatten() -> FlattenCollection<Self>

Declared In

CollectionType

Where Generator.Element : CollectionType, Index : BidirectionalIndexType, Generator.Element.Index : BidirectionalIndexType

func flatten()

A concatenation of the elements of self.

Declaration

func flatten() -> FlattenBidirectionalCollection<Self>

Declared In

CollectionType

Where Generator.Element : Comparable

func lexicographicalCompare(_:)

Returns true iff self precedes other in a lexicographical ("dictionary") ordering, using "<" as the comparison between elements.

Note: This method implements the mathematical notion of lexicographical ordering, which has no connection to Unicode. If you are sorting strings to present to the end-user, you should use String APIs that perform localized comparison.

Declaration

func lexicographicalCompare<OtherSequence : SequenceType where OtherSequence.Generator.Element == Generator.Element>(other: OtherSequence) -> Bool

Declared In

SequenceType
func maxElement()

Returns the maximum element in self or nil if the sequence is empty.

Complexity: O(elements.count).

Declaration

func maxElement() -> Self.Generator.Element?

Declared In

SequenceType
func minElement()

Returns the minimum element in self or nil if the sequence is empty.

Complexity: O(elements.count).

Declaration

func minElement() -> Self.Generator.Element?

Declared In

SequenceType
func sort()

Returns an Array containing the sorted elements of source.

The sorting algorithm is not stable (can change the relative order of elements that compare equal).

Requires: The less-than operator (func <) defined in the Comparable conformance is a strict weak ordering over the elements in self.

Declaration

func sort() -> [Self.Generator.Element]

Declared In

SequenceType

Where Generator.Element : Equatable

func contains(_:)

Returns true iff element is in self.

Declaration

func contains(element: Self.Generator.Element) -> Bool

Declared In

SequenceType
func elementsEqual(_:)

Returns true iff self and other contain the same elements in the same order.

Declaration

func elementsEqual<OtherSequence : SequenceType where OtherSequence.Generator.Element == Generator.Element>(other: OtherSequence) -> Bool

Declared In

SequenceType
func indexOf(_:)

Returns the first index where value appears in self or nil if value is not found.

Complexity: O(self.count).

Declaration

func indexOf(element: Self.Generator.Element) -> Self.Index?

Declared In

CollectionType
func split(_:maxSplit:allowEmptySlices:)

Returns the maximal SubSequences of self, in order, around a separator element.

maxSplit: The maximum number of SubSequences to return, minus 1. If maxSplit + 1 SubSequences are returned, the last one is a suffix of self containing the remaining elements. The default value is Int.max.

allowEmptySubsequences: If true, an empty SubSequence is produced in the result for each pair of consecutive elements satisfying isSeparator. The default value is false.

Requires: maxSplit >= 0

Declaration

func split(separator: Self.Generator.Element, maxSplit: Int = default, allowEmptySlices: Bool = default) -> [Self.SubSequence]

Declared In

CollectionType, SequenceType
func startsWith(_:)

Returns true iff the initial elements of self are equal to prefix. Returns true if other is empty.

Declaration

func startsWith<OtherSequence : SequenceType where OtherSequence.Generator.Element == Generator.Element>(other: OtherSequence) -> Bool

Declared In

SequenceType

Where Generator.Element : SequenceType

func flatten()

A concatenation of the elements of self.

Declaration

func flatten() -> FlattenSequence<Self>

Declared In

SequenceType
func joinWithSeparator(_:)

Returns a view, whose elements are the result of interposing a given separator between the elements of the sequence self.

For example, [[1, 2, 3], [4, 5, 6], [7, 8, 9]].joinWithSeparator([-1, -2]) yields [1, 2, 3, -1, -2, 4, 5, 6, -1, -2, 7, 8, 9].

Declaration

func joinWithSeparator<Separator : SequenceType where Separator.Generator.Element == Generator.Element.Generator.Element>(separator: Separator) -> JoinSequence<Self>

Declared In

SequenceType

Where Generator.Element == String

func joinWithSeparator(_:)

Interpose the separator between elements of self, then concatenate the result. For example:

["foo", "bar", "baz"].joinWithSeparator("-|-") // "foo-|-bar-|-baz"

Declaration

func joinWithSeparator(separator: String) -> String

Declared In

SequenceType

Where Index : BidirectionalIndexType

var last: Self.Generator.Element?

Declaration

var last: Self.Generator.Element? { get }

Declared In

CollectionType
func dropLast(_:)

Returns a subsequence containing all but the last n elements.

Requires: n >= 0 Complexity: O(n)

Declaration

func dropLast(n: Int) -> Self.SubSequence

Declared In

CollectionType
func reverse()

Returns the elements of self in reverse order.

Complexity: O(1)

Declaration

func reverse() -> ReverseCollection<Self>

Declared In

CollectionType
func suffix(_:)

Returns a slice, up to maxLength in length, containing the final elements of s.

If maxLength exceeds s.count, the result contains all the elements of s.

Requires: maxLength >= 0 Complexity: O(maxLength)

Declaration

func suffix(maxLength: Int) -> Self.SubSequence

Declared In

CollectionType

Where Index : RandomAccessIndexType

func reverse()

Returns the elements of self in reverse order.

Complexity: O(1)

Declaration

func reverse() -> ReverseRandomAccessCollection<Self>

Declared In

CollectionType

Where SubSequence : SequenceType, SubSequence.Generator.Element == Generator.Element, SubSequence.SubSequence == SubSequence

func dropFirst(_:)

Returns a subsequence containing all but the first n elements.

Requires: n >= 0 Complexity: O(n)

Declaration

func dropFirst(n: Int) -> AnySequence<Self.Generator.Element>

Declared In

SequenceType
func dropLast(_:)

Returns a subsequence containing all but the last n elements.

Requires: self is a finite collection. Requires: n >= 0 Complexity: O(self.count)

Declaration

func dropLast(n: Int) -> AnySequence<Self.Generator.Element>

Declared In

SequenceType
func prefix(_:)

Returns a subsequence, up to maxLength in length, containing the initial elements.

If maxLength exceeds self.count, the result contains all the elements of self.

Requires: maxLength >= 0

Declaration

func prefix(maxLength: Int) -> AnySequence<Self.Generator.Element>

Declared In

SequenceType

Where SubSequence == Self

mutating func popFirst()

If !self.isEmpty, remove the first element and return it, otherwise return nil.

Complexity: O(1)

Declaration

mutating func popFirst() -> Self.Generator.Element?

Declared In

CollectionType
mutating func popLast()

If !self.isEmpty, remove the last element and return it, otherwise return nil.

Complexity: O(self.count)

Deprecated: it will be removed in Swift 3.

Declaration

mutating func popLast() -> Self.Generator.Element?

Declared In

CollectionType
mutating func removeFirst()

Remove the element at startIndex and return it.

Complexity: O(1) Requires: !self.isEmpty.

Declaration

mutating func removeFirst() -> Self.Generator.Element

Declared In

CollectionType
mutating func removeFirst(_:)

Remove the first n elements.

Complexity: - O(1) if Index conforms to RandomAccessIndexType - O(n) otherwise Requires: n >= 0 && self.count >= n.

Declaration

mutating func removeFirst(n: Int)

Declared In

CollectionType

Where SubSequence == Self, Index : BidirectionalIndexType

mutating func popLast()

If !self.isEmpty, remove the last element and return it, otherwise return nil.

Complexity: O(1)

Declaration

mutating func popLast() -> Self.Generator.Element?

Declared In

CollectionType
mutating func removeLast()

Remove an element from the end.

Complexity: O(1) Requires: !self.isEmpty

Declaration

mutating func removeLast() -> Self.Generator.Element

Declared In

CollectionType
mutating func removeLast(_:)

Remove the last n elements.

Complexity: - O(1) if Index conforms to RandomAccessIndexType - O(n) otherwise Requires: n >= 0 && self.count >= n.

Declaration

mutating func removeLast(n: Int)

Declared In

CollectionType

Where SubSequence == Slice

subscript(_: Range<Self.Index>)

Returns a collection representing a contiguous sub-range of self's elements.

Complexity: O(1)

Declaration

subscript(bounds: Range<Self.Index>) -> Slice<Self> { get }

Declared In

CollectionType