# compactMap(_:) Returns an array containing the non-`nil` results of calling the given transformation with each element of this sequence. ``` func compactMap(_ transform: (Self.Element) throws -> ElementOfResult?) rethrows -> [ElementOfResult] ``` ## Parameters `transform` A closure that accepts an element of this sequence as its argument and returns an optional value. ## Return Value An array of the non-`nil` results of calling `transform` with each element of the sequence. ## Discussion Use this method to receive an array of non-optional values when your transformation produces an optional value. In this example, note the difference in the result of using `map` and `compactMap` with a transformation that returns an optional `Int` value. ``` let possibleNumbers = ["1", "2", "three", "///4///", "5"] let mapped: [Int?] = possibleNumbers.map { str in Int(str) } // [1, 2, nil, nil, 5] let compactMapped: [Int] = possibleNumbers.compactMap { str in Int(str) } // [1, 2, 5] ``` > Complexity: O(*n*), where *n* is the length of this sequence. --- 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)