Subscript

subscript(_:)

Accesses the element at the specified position.

Declaration

subscript(index: Int) -> Element { get set }

Parameters

index

The position of the element to access. index must be greater than or equal to startIndex and less than endIndex.

Discussion

The following example uses indexed subscripting to update an array’s second element. After assigning the new value ("Butler") at a specific position, that value is immediately available at that same position.

var streets = ["Adams", "Bryant", "Channing", "Douglas", "Evarts"]
streets[1] = "Butler"
print(streets[1])
// Prints "Butler"

Complexity: Reading an element from an array is O(1). Writing is O(1) unless the array’s storage is shared with another array or uses a bridged NSArray instance as its storage, in which case writing is O(n), where n is the length of the array.