# Collection Implementations ## Topics ### Instance Properties [`var count: Int`](/documentation/Swift/AnyCollection/count) The number of elements. [`var endIndex: AnyCollection.Index`](/documentation/Swift/AnyCollection/endIndex) The collection’s “past the end” position—that is, the position one greater than the last valid subscript argument. [`var first: Self.Element?`](/documentation/Swift/AnyCollection/first) The first element of the collection. [`var indices: DefaultIndices`](/documentation/Swift/AnyCollection/indices-swift.property) The indices that are valid for subscripting the collection, in ascending order. [`var isEmpty: Bool`](/documentation/Swift/AnyCollection/isEmpty) A Boolean value indicating whether the collection is empty. [`var startIndex: AnyCollection.Index`](/documentation/Swift/AnyCollection/startIndex) The position of the first element in a non-empty collection. ### Instance Methods [`func distance(from: AnyCollection.Index, to: AnyCollection.Index) -> Int`](/documentation/Swift/AnyCollection/distance(from:to:)) Returns the distance between two indices. [`func firstIndex(of: Self.Element) -> Self.Index?`](/documentation/Swift/AnyCollection/firstIndex(of:)) Returns the first index where the specified value appears in the collection. [`func firstIndex(where: (Self.Element) throws -> Bool) rethrows -> Self.Index?`](/documentation/Swift/AnyCollection/firstIndex(where:)) Returns the first index in which an element of the collection satisfies the given predicate. [`func formIndex(after: inout AnyCollection.Index)`](/documentation/Swift/AnyCollection/formIndex(after:)) Replaces the given index with its successor. [`func index(AnyCollection.Index, offsetBy: Int) -> AnyCollection.Index`](/documentation/Swift/AnyCollection/index(_:offsetBy:)) Returns an index that is the specified distance from the given index. [`func index(AnyCollection.Index, offsetBy: Int, limitedBy: AnyCollection.Index) -> AnyCollection.Index?`](/documentation/Swift/AnyCollection/index(_:offsetBy:limitedBy:)) Returns an index that is the specified distance from the given index, unless that distance is beyond a given limiting index. [`func index(after: AnyCollection.Index) -> AnyCollection.Index`](/documentation/Swift/AnyCollection/index(after:)) Returns the position immediately after the given index. [`func index(of: Self.Element) -> Self.Index?`](/documentation/Swift/AnyCollection/index(of:)) Returns the first index where the specified value appears in the collection. [`func indices(of: Self.Element) -> RangeSet`](/documentation/Swift/AnyCollection/indices(of:)) Returns the indices of all the elements that are equal to the given element. [`func indices(where: (Self.Element) throws -> Bool) rethrows -> RangeSet`](/documentation/Swift/AnyCollection/indices(where:)) Returns the indices of all the elements that match the given predicate. [`func makeIterator() -> AnyCollection.Iterator`](/documentation/Swift/AnyCollection/makeIterator()) Returns an iterator over the elements of this collection. [`func map((Self.Element) throws(E) -> T) throws(E) -> [T]`](/documentation/Swift/AnyCollection/map(_:)-2u3hq) Returns an array containing the results of mapping the given closure over the sequence’s elements. [`func popFirst() -> Self.Element?`](/documentation/Swift/AnyCollection/popFirst()) Removes and returns the first element of the collection. [`func prefix(through: Self.Index) -> Self.SubSequence`](/documentation/Swift/AnyCollection/prefix(through:)) Returns a subsequence from the start of the collection through the specified position. [`func prefix(upTo: Self.Index) -> Self.SubSequence`](/documentation/Swift/AnyCollection/prefix(upTo:)) Returns a subsequence from the start of the collection up to, but not including, the specified position. [`func randomElement() -> Self.Element?`](/documentation/Swift/AnyCollection/randomElement()) Returns a random element of the collection. [`func randomElement(using: inout T) -> Self.Element?`](/documentation/Swift/AnyCollection/randomElement(using:)) Returns a random element of the collection, using the given generator as a source for randomness. [`func removeFirst() -> Self.Element`](/documentation/Swift/AnyCollection/removeFirst()) Removes and returns the first element of the collection. [`func removeFirst(Int)`](/documentation/Swift/AnyCollection/removeFirst(_:)) Removes the specified number of elements from the beginning of the collection. [`func removingSubranges(RangeSet) -> DiscontiguousSlice`](/documentation/Swift/AnyCollection/removingSubranges(_:)) Returns a collection of the elements in this collection that are not represented by the given range set. [`func split(maxSplits: Int, omittingEmptySubsequences: Bool, whereSeparator: (Self.Element) throws -> Bool) rethrows -> [Self.SubSequence]`](/documentation/Swift/AnyCollection/split(maxSplits:omittingEmptySubsequences:whereSeparator:)) Returns the longest possible subsequences of the collection, in order, that don’t contain elements satisfying the given predicate. [`func split(separator: Self.Element, maxSplits: Int, omittingEmptySubsequences: Bool) -> [Self.SubSequence]`](/documentation/Swift/AnyCollection/split(separator:maxSplits:omittingEmptySubsequences:)-52osm) Returns the longest possible subsequences of the collection, in order, around elements equal to the given element. [`func suffix(from: Self.Index) -> Self.SubSequence`](/documentation/Swift/AnyCollection/suffix(from:)) Returns a subsequence from the specified position to the end of the collection. ### Subscripts [`subscript(RangeSet) -> DiscontiguousSlice`](/documentation/Swift/AnyCollection/subscript(_:)-47haf) Accesses a view of this collection with the elements at the given indices. [`subscript(AnyCollection.Index) -> Element`](/documentation/Swift/AnyCollection/subscript(_:)-87z1l) Accesses the element indicated by `position`. [`subscript(UnboundedRange) -> Self.SubSequence`](/documentation/Swift/AnyCollection/subscript(_:)-9guhy) [`subscript(R) -> Self.SubSequence`](/documentation/Swift/AnyCollection/subscript(_:)-t0ed) Accesses the contiguous subrange of the collection’s elements specified by a range expression. [`subscript(Range.Index>) -> AnyCollection.SubSequence`](/documentation/Swift/AnyCollection/subscript(_:)-vb3o) Accesses a contiguous subrange of the collection’s elements. ### Type Aliases [`typealias Index`](/documentation/Swift/AnyCollection/Index) A type that represents a position in the collection. [`typealias Indices`](/documentation/Swift/AnyCollection/Indices) A type that represents the indices that are valid for subscripting the collection, in ascending order. [`typealias Iterator`](/documentation/Swift/AnyCollection/Iterator) A type that provides the collection’s iteration interface and encapsulates its iteration state. [`typealias SubSequence`](/documentation/Swift/AnyCollection/SubSequence) A collection representing a contiguous subrange of this collection’s elements. The subsequence shares indices with the original collection. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)