# ~(_:) Returns the inverse of the bits set in the argument. ``` static func ~ (x: Self) -> Self ``` ## Discussion The bitwise NOT operator (`~`) is a prefix operator that returns a value in which all the bits of its argument are flipped: Bits that are `1` in the argument are `0` in the result, and bits that are `0` in the argument are `1` in the result. This is equivalent to the inverse of a set. For example: ``` let x: UInt8 = 5 // 0b00000101 let notX = ~x // 0b11111010 ``` Performing a bitwise NOT operation on 0 returns a value with every bit set to `1`. ``` let allOnes = ~UInt8.min // 0b11111111 ``` > Complexity: O(1). --- 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)