# stride(from:through:by:) Returns a sequence from a starting value toward, and possibly including, an end value, stepping by the specified amount. ``` func stride(from start: T, through end: T, by stride: T.Stride) -> StrideThrough where T : Strideable ``` ## Parameters `start` The starting value to use for the sequence. If the sequence contains any values, the first one is `start`. `end` An end value to limit the sequence. `end` is an element of the resulting sequence if and only if it can be produced from `start` using steps of `stride`. `stride` The amount to step by with each iteration. A positive `stride` iterates upward; a negative `stride` iterates downward. ## Return Value A sequence from `start` toward, and possibly including, `end`. Each value in the sequence is separated by `stride`. ## Discussion You can use this function to stride over values of any type that conforms to the `Strideable` protocol, such as integers or floating-point types. Starting with `start`, each successive value of the sequence adds `stride` until the next value would be beyond `end`. ``` for radians in stride(from: 0.0, through: .pi * 2, by: .pi / 2) { let degrees = Int(radians * 180 / .pi) print("Degrees: \(degrees), radians: \(radians)") } // Degrees: 0, radians: 0.0 // Degrees: 90, radians: 1.5707963267949 // Degrees: 180, radians: 3.14159265358979 // Degrees: 270, radians: 4.71238898038469 // Degrees: 360, radians: 6.28318530717959 ``` You can use `stride(from:through:by:)` to create a sequence that strides upward or downward. Pass a negative value as `stride` to create a sequence from a higher start to a lower end: ``` for countdown in stride(from: 3, through: 1, by: -1) { print("\(countdown)...") } // 3... // 2... // 1... ``` The value you pass as `end` is not guaranteed to be included in the sequence. If stepping from `start` by `stride` does not produce `end`, the last value in the sequence will be one step before going beyond `end`. ``` for multipleOfThree in stride(from: 3, through: 10, by: 3) { print(multipleOfThree) } // 3 // 6 // 9 ``` If you pass a value as `stride` that moves away from `end`, the sequence contains no values. ``` for x in stride(from: 0, through: 10, by: -1) { print(x) } // Nothing is printed. ``` --- 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)