protocol CollectionType| Inheritance |
Indexable, SequenceType
View Protocol Hierarchy →
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| Associated Types |
Generator : GeneratorType = IndexingGenerator<Self>
A type that provides the sequence's iteration interface and encapsulates its iteration state. By default, a SubSequence : Indexable, SequenceType = Slice<Self>
A Note: This associated type appears as a requirement in
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| Import | import Swift |
Instance Variables
Returns the number of elements.
Complexity: O(1) if Index conforms to RandomAccessIndexType;
O(N) otherwise.
Declaration
var count: Self.Index.Distance { get }
Returns the first element of self, or nil if self is empty.
Declaration
var first: Self.Generator.Element? { get }
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
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
Returns a collection representing a contiguous sub-range of
self's elements.
Complexity: O(1)
Declaration
subscript(bounds: Range<Self.Index>) -> Self.SubSequence { get }
Returns the element at the given position.
Declaration
subscript(position: Self.Index) -> Self.Generator.Element { get }
Declared In
CollectionType, Indexable
Instance Methods
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
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
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
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
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
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
Returns prefixUpTo(position.successor())
Complexity: O(1)
Declaration
func prefixThrough(position: Self.Index) -> Self.SubSequence
Returns self[startIndex..<end]
Complexity: O(1)
Declaration
func prefixUpTo(end: Self.Index) -> Self.SubSequence
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
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
Returns self[start..<endIndex]
Complexity: O(1)
Declaration
func suffixFrom(start: Self.Index) -> Self.SubSequence
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
Returns the number of elements.
Complexity: O(1) if Index conforms to RandomAccessIndexType;
O(N) otherwise.
Declaration
var count: Self.Index.Distance { get }
Returns the first element of self, or nil if self is empty.
Complexity: O(1)
Declaration
var first: Self.Generator.Element? { get }
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 }
Returns true iff self is empty.
Complexity: O(1)
Declaration
var isEmpty: Bool { get }
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 }
Returns true iff an element in self satisfies predicate.
Declaration
func contains(@noescape predicate: (Self.Generator.Element) throws -> Bool) rethrows -> Bool
Declared In
SequenceType
Returns a subsequence containing all but the first element.
Complexity: O(1)
Declaration
func dropFirst() -> Self.SubSequence
Declared In
SequenceType
Returns a subsequence containing all but the first n elements.
Requires: n >= 0
Complexity: O(n)
Declaration
func dropFirst(n: Int) -> Self.SubSequence
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
Returns a subsequence containing all but the last n elements.
Requires: n >= 0
Complexity: O(self.count)
Declaration
func dropLast(n: Int) -> Self.SubSequence
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
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
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
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
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
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
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?
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
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
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
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
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
Returns prefixUpTo(position.successor())
Complexity: O(1)
Declaration
func prefixThrough(position: Self.Index) -> Self.SubSequence
Returns self[startIndex..<end]
Complexity: O(1)
Declaration
func prefixUpTo(end: Self.Index) -> Self.SubSequence
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
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
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
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
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
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
Returns self[start..<endIndex]
Complexity: O(1)
Declaration
func suffixFrom(start: Self.Index) -> Self.SubSequence
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
Where Generator == Self, Self : GeneratorType
Returns a generator over the elements of this sequence.
Complexity: O(1).
Declaration
func generate() -> Self
Declared In
SequenceType
Where Generator.Element : CollectionType
A concatenation of the elements of self.
Declaration
func flatten() -> FlattenCollection<Self>
Where Generator.Element : CollectionType, Index : BidirectionalIndexType, Generator.Element.Index : BidirectionalIndexType
A concatenation of the elements of self.
Declaration
func flatten() -> FlattenBidirectionalCollection<Self>
Where Generator.Element : Comparable
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
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
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
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
Returns true iff element is in self.
Declaration
func contains(element: Self.Generator.Element) -> Bool
Declared In
SequenceType
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
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?
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
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
A concatenation of the elements of self.
Declaration
func flatten() -> FlattenSequence<Self>
Declared In
SequenceType
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
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
Returns a subsequence containing all but the last n elements.
Requires: n >= 0
Complexity: O(n)
Declaration
func dropLast(n: Int) -> Self.SubSequence
Returns the elements of self in reverse order.
Complexity: O(1)
Declaration
func reverse() -> ReverseCollection<Self>
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
Where Index : RandomAccessIndexType
Returns the elements of self in reverse order.
Complexity: O(1)
Declaration
func reverse() -> ReverseRandomAccessCollection<Self>
Where Self : _CollectionWrapperType, Index == Base.Index
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().
Declaration
var endIndex: Self.Index { get }
The position of the first element in a non-empty collection.
In an empty collection, startIndex == endIndex.
Declaration
var startIndex: Self.Index { get }
Access the element at position.
Requires: position is a valid position in self and
position != endIndex.
Declaration
subscript(position: Self.Index) -> Self.Base.Generator.Element { get }
Declaration
func filter(@noescape includeElement: (Self.Base.Generator.Element) -> Bool) -> [Self.Base.Generator.Element]
Declaration
func map<T>(@noescape transform: (Self.Base.Generator.Element) -> T) -> [T]
Where Self : _ReverseCollectionType, Base.Index : RandomAccessIndexType
Declaration
var startIndex: ReverseRandomAccessIndex<Self.Base.Index> { get }
Where SubSequence : SequenceType, SubSequence.Generator.Element == Generator.Element, SubSequence.SubSequence == SubSequence
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
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
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
If !self.isEmpty, remove the first element and return it, otherwise
return nil.
Complexity: O(1)
Declaration
mutating func popFirst() -> Self.Generator.Element?
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?
Remove the element at startIndex and return it.
Complexity: O(1)
Requires: !self.isEmpty.
Declaration
mutating func removeFirst() -> Self.Generator.Element
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)
Where SubSequence == Self, Index : BidirectionalIndexType
If !self.isEmpty, remove the last element and return it, otherwise
return nil.
Complexity: O(1)
Declaration
mutating func popLast() -> Self.Generator.Element?
Remove an element from the end.
Complexity: O(1)
Requires: !self.isEmpty
Declaration
mutating func removeLast() -> Self.Generator.Element
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)
Where SubSequence == Slice
Declaration
subscript(bounds: Range<Self.Index>) -> Slice<Self> { get }
A multi-pass sequence with addressable positions.
Positions are represented by an associated
Indextype. Whereas an arbitrary sequence may be consumed as it is traversed, a collection is multi-pass: any element may be revisited merely by saving its index.The sequence view of the elements is identical to the collection view. In other words, the following code binds the same series of values to
xas doesfor x in self {}: