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Safely index items within a collection


We can make some great things with extensions in Swift, as well as subscript functions. This one allows us to safely access collection elements by index, getting back an optional instead of errors being thrown!

extension Collection {
    subscript(safe index: Index) -> Element? {
        indices.contains(index) ? self[index] : nil

let numbers = [1, 2, 3, 4]
numbers[safe: 3] // 4
numbers[safe: 10] // nil, no error

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Andrew Lord

A software developer and tech leader from the UK. Writing articles that focus on all aspects of Android and iOS development using Kotlin and Swift.

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