Arrays in Swift
From the Swift cheat sheet · Collections · verified Jul 2026
Arrays
Ordered collections of values
swift
// Array creation
var numbers = [1, 2, 3, 4, 5]
var emptyArray: [String] = []
var anotherEmpty = [String]()
// Array operations
numbers.append(6)
numbers.insert(0, at: 0)
numbers.remove(at: 2)
let first = numbers.first // Optional
let last = numbers.last // Optional
// Array methods
let doubled = numbers.map { $0 * 2 }
let evens = numbers.filter { $0 % 2 == 0 }
let sum = numbers.reduce(0, +)💡 Arrays are value types - they are copied when assigned
⚡ Use reserveCapacity for better performance with large arrays
📌 ArraySlice shares indices with original array
🟢 Higher-order functions (map, filter, reduce) enable functional programming
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