Subscript

subscript(_:)

Accesses a contiguous subrange of the collection’s elements.

Required.

Declaration

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

Parameters

bounds

A range of the collection’s indices. The bounds of the range must be valid indices of the collection.

Discussion

The accessed slice uses the same indices for the same elements as the original collection uses. Always use the slice’s startIndex property instead of assuming that its indices start at a particular value.

This example demonstrates getting a slice of an array of strings, finding the index of one of the strings in the slice, and then using that index in the original array.

let streets = ["Adams", "Bryant", "Channing", "Douglas", "Evarts"]
let streetsSlice = streets[2 ..< streets.endIndex]
print(streetsSlice)
// Prints "["Channing", "Douglas", "Evarts"]"

let index = streetsSlice.firstIndex(of: "Evarts")    // 4
print(streets[index!])
// Prints "Evarts"