# random(in:using:) Returns a random value within the specified range, using the given generator as a source for randomness. ``` static func random(in range: ClosedRange, using generator: inout T) -> Self where T : RandomNumberGenerator ``` ## Parameters `range` The range in which to create a random value. Must be finite. `generator` The random number generator to use when creating the new random value. ## Return Value A random value within the bounds of `range`. ## Discussion Use this method to generate a floating-point value within a specific range when you are using a custom random number generator. This example creates three new values in the range `10.0 ... 20.0`. ``` for _ in 1...3 { print(Double.random(in: 10.0 ... 20.0, using: &myGenerator)) } // Prints "18.1900709259179" // Prints "14.2286325689993" // Prints "13.1485686260762" ``` The `random(in:using:)` static method chooses a random value from a continuous uniform distribution in `range`, and then converts that value to the nearest representable value in this type. Depending on the size and span of `range`, some concrete values may be represented more frequently than others. > Note: The algorithm used to create random values may change in a future > version of Swift. If you’re passing a generator that results in the > same sequence of floating-point values each time you run your program, > that sequence may change when your program is compiled using a > different version of Swift. --- 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)