struct Array<Element>| Inheritance |
ArrayLiteralConvertible, CollectionType, CustomDebugStringConvertible, CustomStringConvertible, Indexable, MutableCollectionType, MutableIndexable, MutableSliceable, RangeReplaceableCollectionType, SequenceType, _ArrayType, _DestructorSafeContainer, _Reflectable
View Protocol Hierarchy →
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| Associated Types | |
| Import | import Swift |
Initializers
Construct from an arbitrary sequence with elements of type Element.
Declaration
init<S : SequenceType where S.Generator.Element == _Buffer.Element>(_ s: S)
Declared In
Array
, RangeReplaceableCollectionType
Create an instance containing elements.
Declaration
init(arrayLiteral elements: Element...)
Construct a Array of count elements, each initialized to
repeatedValue.
Declaration
init(count: Int, repeatedValue: Element)
Instance Variables
The number of elements the Array can store without reallocation.
Declaration
var capacity: Int { get }
A textual representation of self, suitable for debugging.
Declaration
var debugDescription: String { get }
A textual representation of self.
Declaration
var description: String { get }
A "past-the-end" element index; the successor of the last valid subscript argument.
Declaration
var endIndex: Int { get }
Returns the first element of self, or nil if self is empty.
Complexity: O(1)
Declaration
var first: Element? { get }
Declared In
CollectionType
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<Int> { get }
Declared In
CollectionType
Returns true iff self is empty.
Complexity: O(1)
Declaration
var isEmpty: Bool { get }
Declared In
CollectionType
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<Array<Element>> { get }
Declared In
CollectionType
Always zero, which is the index of the first element when non-empty.
Declaration
var startIndex: Int { get }
Subscripts
Access the indexth element. Reading is O(1). Writing is
O(1) unless self's storage is shared with another live array; O(count) if self does not wrap a bridged NSArray; otherwise the efficiency is unspecified..
Declaration
subscript(index: Int) -> Element
Access the elements indicated by the given half-open subRange.
Complexity: O(1).
Declaration
subscript(subRange: Range<Int>) -> ArraySlice<Element>
Declared In
Array, MutableCollectionType
Instance Methods
Append newElement to the Array.
Complexity: Amortized O(1) unless self's storage is shared with another live array; O(count) if self does not wrap a bridged NSArray; otherwise the efficiency is unspecified..
Declaration
mutating func append(newElement: Element)
Declared In
Array, RangeReplaceableCollectionType
Append the elements of newElements to self.
Complexity: O(length of result).
Declaration
mutating func appendContentsOf<S : SequenceType where S.Generator.Element == Element>(newElements: S)
Append the elements of newElements to self.
Complexity: O(length of result).
Declaration
mutating func appendContentsOf<C : CollectionType where C.Generator.Element == Element>(newElements: C)
Append the elements of newElements to self.
Complexity: O(length of result).
Declaration
mutating func appendContentsOf<S : SequenceType where S.Generator.Element == Generator.Element>(newElements: S)
Declared In
RangeReplaceableCollectionType
Returns true iff an element in self satisfies predicate.
Declaration
func contains(@noescape predicate: (Element) throws -> Bool) rethrows -> Bool
Declared In
SequenceType
Returns a subsequence containing all but the first element.
Complexity: O(1)
Declaration
func dropFirst() -> ArraySlice<Element>
Declared In
SequenceType
Returns a subsequence containing all but the first n elements.
Requires: n >= 0
Complexity: O(n)
Declaration
func dropFirst(n: Int) -> ArraySlice<Element>
Declared In
CollectionType, SequenceType
Returns a subsequence containing all but the last element.
Requires: self is a finite sequence.
Complexity: O(self.count)
Declaration
func dropLast() -> ArraySlice<Element>
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) -> ArraySlice<Element>
Declared In
CollectionType, SequenceType
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: (Element, 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<Array<Element>>
Declared In
SequenceType
Returns an Array containing the elements of self,
in order, that satisfy the predicate includeElement.
Declaration
func filter(@noescape includeElement: (Element) throws -> Bool) rethrows -> [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: (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: (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: (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: (Element) throws -> Bool) rethrows -> Int?
Declared In
CollectionType
Insert newElement at index i.
Requires: i <= count.
Complexity: O(self.count).
Declaration
mutating func insert(newElement: Element, atIndex i: Int)
Declared In
Array, RangeReplaceableCollectionType
Insert newElements at index i.
Invalidates all indices with respect to self.
Complexity: O(self.count + newElements.count).
Declaration
mutating func insertContentsOf<C : CollectionType where C.Generator.Element == Generator.Element>(newElements: C, at i: Int)
Declared In
RangeReplaceableCollectionType
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: (Element, 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: (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: (Element, Element) throws -> Bool) rethrows -> 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: (Element, Element) throws -> Bool) rethrows -> Element?
Declared In
SequenceType
Re-order the given range of elements in self and return
a pivot index p.
Postcondition: For all i in range.startIndex..<p, and j
in p..<range.endIndex, less(self[i],
self[j]) && !less(self[j], self[p]).
Only returns range.endIndex when self is empty.
Requires: isOrderedBefore is a
strict weak ordering
over the elements in self.
Declaration
mutating func partition(range: Range<Int>, isOrderedBefore: (Element, Element) -> Bool) -> Int
Declared In
MutableCollectionType
If !self.isEmpty, remove the last element and return it, otherwise
return nil.
Complexity: O(self.count) if the array is bridged,
otherwise O(1).
Declaration
mutating func popLast() -> Element?
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) -> ArraySlice<Element>
Declared In
CollectionType, SequenceType
Returns prefixUpTo(position.successor())
Complexity: O(1)
Declaration
func prefixThrough(position: Int) -> ArraySlice<Element>
Declared In
CollectionType
Returns self[startIndex..<end]
Complexity: O(1)
Declaration
func prefixUpTo(end: Int) -> ArraySlice<Element>
Declared In
CollectionType
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, Element) throws -> T) rethrows -> T
Declared In
SequenceType
Remove all elements.
Postcondition: capacity == 0 iff keepCapacity is false.
Complexity: O(self.count).
Declaration
mutating func removeAll(keepCapacity keepCapacity: Bool = default)
Declared In
Array, RangeReplaceableCollectionType
Remove and return the element at index i.
Invalidates all indices with respect to self.
Complexity: O(self.count).
Declaration
mutating func removeAtIndex(index: Int) -> Element
Declared In
Array, RangeReplaceableCollectionType
Remove the element at startIndex and return it.
Complexity: O(self.count)
Requires: !self.isEmpty.
Declaration
mutating func removeFirst() -> Element
Declared In
RangeReplaceableCollectionType
Remove the first n elements.
Complexity: O(self.count)
Requires: n >= 0 && self.count >= n.
Declaration
mutating func removeFirst(n: Int)
Declared In
RangeReplaceableCollectionType
Remove an element from the end of the Array in O(1).
Requires: count > 0.
Declaration
mutating func removeLast() -> Element
Declared In
Array, RangeReplaceableCollectionType
Remove the last n elements.
Complexity: O(self.count)
Requires: n >= 0 && self.count >= n.
Declaration
mutating func removeLast(n: Int)
Declared In
RangeReplaceableCollectionType
Remove the indicated subRange of elements.
Invalidates all indices with respect to self.
Complexity: O(self.count).
Declaration
mutating func removeRange(subRange: Range<Int>)
Declared In
RangeReplaceableCollectionType
Replace the given subRange of elements with newElements.
Complexity: O(subRange.count) if subRange.endIndex
== self.endIndex and newElements.isEmpty, O(N) otherwise.
Declaration
mutating func replaceRange<C : CollectionType where C.Generator.Element == _Buffer.Element>(subRange: Range<Int>, with newElements: C)
Reserve enough space to store minimumCapacity elements.
Postcondition: capacity >= minimumCapacity and the array has
mutable contiguous storage.
Complexity: O(self.count).
Declaration
mutating func reserveCapacity(minimumCapacity: Int)
Declared In
Array, RangeReplaceableCollectionType
Returns the elements of self in reverse order.
Complexity: O(1)
Declaration
func reverse() -> ReverseCollection<Array<Element>>
Declared In
CollectionType, 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: (Element, Element) -> Bool) -> [Element]
Declared In
MutableCollectionType, SequenceType
Sort self in-place 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
mutating func sortInPlace(@noescape isOrderedBefore: (Element, Element) -> Bool)
Declared In
MutableCollectionType
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: (Element) throws -> Bool) rethrows -> [ArraySlice<Element>]
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: (Element, 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) -> ArraySlice<Element>
Declared In
CollectionType, SequenceType
Returns self[start..<endIndex]
Complexity: O(1)
Declaration
func suffixFrom(start: Int) -> ArraySlice<Element>
Declared In
CollectionType
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
Call body(p), where p is a pointer to the Array's
contiguous storage. If no such storage exists, it is first created.
Often, the optimizer can eliminate bounds checks within an
array algorithm, but when that fails, invoking the
same algorithm on body's argument lets you trade safety for
speed.
Declaration
func withUnsafeBufferPointer<R>(@noescape body: (UnsafeBufferPointer<Element>) throws -> R) rethrows -> R
Call body(p), where p is a pointer to the Array's
mutable contiguous storage. If no such storage exists, it is first created.
Often, the optimizer can eliminate bounds- and uniqueness-checks
within an array algorithm, but when that fails, invoking the
same algorithm on body's argument lets you trade safety for
speed.
Warning: Do not rely on anything about self (the Array
that is the target of this method) during the execution of
body: it may not appear to have its correct value. Instead,
use only the UnsafeMutableBufferPointer argument to body.
Declaration
mutating func withUnsafeMutableBufferPointer<R>(@noescape body: (inout UnsafeMutableBufferPointer<Element>) throws -> R) rethrows -> R
Conditionally Inherited Items
The initializers, methods, and properties listed below may be available on this type under certain conditions (such as methods that are available on Array when its elements are Equatable) or may not ever be available if that determination is beyond SwiftDoc.org's capabilities. Please open an issue on GitHub if you see something out of place!
Where Generator.Element : CollectionType
A concatenation of the elements of self.
Declaration
func flatten() -> FlattenCollection<Array<Element>>
Declared In
CollectionType
Where Generator.Element : CollectionType, Index : BidirectionalIndexType, Generator.Element.Index : BidirectionalIndexType
A concatenation of the elements of self.
Declaration
func flatten() -> FlattenBidirectionalCollection<Array<Element>>
Declared In
CollectionType
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() -> Element?
Declared In
SequenceType
Returns the minimum element in self or nil if the sequence is empty.
Complexity: O(elements.count).
Declaration
func minElement() -> 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() -> [Element]
Declared In
MutableCollectionType, SequenceType
Where Generator.Element : Equatable
Returns true iff element is in self.
Declaration
func contains(element: 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: Element) -> Int?
Declared In
CollectionType
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: Element, maxSplit: Int = default, allowEmptySlices: Bool = default) -> [ArraySlice<Element>]
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<Array<Element>>
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<Array<Element>>
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 : RandomAccessIndexType, Generator.Element : Comparable
Re-order the given range of elements in self and return
a pivot index p.
Postcondition: For all i in range.startIndex..<p, and j
in p..<range.endIndex, less(self[i],
self[j]) && !less(self[j], self[p]).
Only returns range.endIndex when self is empty.
Requires: The less-than operator (func <) defined in
the Comparable conformance is a
strict weak ordering
over the elements in self.
Declaration
mutating func partition(range: Range<Int>) -> Int
Declared In
MutableCollectionType
Sort self in-place.
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
mutating func sortInPlace()
Declared In
MutableCollectionType
Arrayis an efficient, tail-growable random-access collection of arbitrary elements.Common Properties of Array Types
The information in this section applies to all three of Swift's array types,
Array<Element>,ContiguousArray<Element>, andArraySlice<Element>. When you read the word "array" here in a normal typeface, it applies to all three of them.Value Semantics
Each array variable,
letbinding, or stored property has an independent value that includes the values of all of its elements. Therefore, mutations to the array are not observable through its copies:(Of course, if the array stores
classreferences, the objects are shared; only the values of the references are independent.)Arrays use Copy-on-Write so that their storage and elements are only copied lazily, upon mutation, when more than one array instance is using the same buffer. Therefore, the first in any sequence of mutating operations may cost
O(N)time and space, whereNis the length of the array.Growth and Capacity
When an array's contiguous storage fills up, new storage must be allocated and elements must be moved to the new storage.
Array,ContiguousArray, andArraySliceshare an exponential growth strategy that makesappenda constant time operation when amortized over many invocations. In addition to acountproperty, these array types have acapacitythat reflects their potential to store elements without reallocation, and when you know how many elements you'll store, you can callreserveCapacityto preemptively reallocate and prevent intermediate reallocations.Objective-C Bridge
The main distinction between
Arrayand the other array types is that it interoperates seamlessly and efficiently with Objective-C.Array<Element>is considered bridged to Objective-C iffElementis bridged to Objective-C.When
Elementis aclassor@objcprotocol type,Arraymay store its elements in anNSArray. Since any arbitrary subclass ofNSArraycan become anArray, there are no guarantees about representation or efficiency in this case (see alsoContiguousArray). SinceNSArrayis immutable, it is just as though the storage was shared by some copy: the first in any sequence of mutating operations causes elements to be copied into unique, contiguous storage which may costO(N)time and space, whereNis the length of the array (or more, if the underlyingNSArrayhas unusual performance characteristics).Bridging to Objective-C
Any bridged
Arraycan be implicitly converted to anNSArray. WhenElementis aclassor@objcprotocol, bridging takes O(1) time and O(1) space. OtherArrays must be bridged element-by-element, allocating a new object for each element, at a cost of at least O(count) time and space.Bridging from Objective-C
An
NSArraycan be implicitly or explicitly converted to any bridgedArray<Element>. This conversion callscopyWithZoneon theNSArray, to ensure it won't be modified, and stores the result in theArray. Type-checking, to ensure theNSArray's elements match or can be bridged toElement, is deferred until the first element access.