Easy randoms in Swift

Randoms.swift

//
//  Randoms.swift
//
//  Created by Ayden Panhuyzen on 2018-03-17.
//  Copyright © 2018 Ayden Panhuyzen. All rights reserved.
//  https://gist.github.com/aydenp
//

import UIKit

// MARK: Integers

extension BinaryInteger {
    /// Returns a random integer between min and max.
    public static func random(min: Self = 0, max: Self) -> Self {
        return .random(n: max - min + 1) + min
    }
    
    /// Returns a random integer between 0 and n-1.
    public static func random(n: Self) -> Self {
        return Self(arc4random_uniform(UInt32(n)))
    }
}

extension Int {
    /// Returns a random Int point number between 0 and Int.max.
    public static var random: Int {
        return .random(n: .max)
    }
}

// MARK: Floating Point Numbers

extension FloatingPoint {
    /// Returns a random floating point number between 0.0 and 1.0, inclusive.
    public static var random: Self {
        return Self(arc4random()) / 0xFFFFFFFF
    }
    
    /// Returns a random floating point number between min and max.
    public static func random(min: Self = 0, max: Self) -> Self {
        return .random * (max - min) + min
    }
}

// MARK: Booleans

extension Bool {
    /// Returns a random boolean.
    public static var random: Bool {
        return .random(probability: 1)
    }
    
    /// Returns a random boolean with the chance of being true probability:1.
    public static func random(probability: Int) -> Bool {
        return Int.random(n: probability + 1) <= 0
    }
}

// MARK: Collections

extension RandomAccessCollection {
    /// Returns a random item from the array
    public var random: Element {
        let offset = Int.random(min: 0, max: numericCast(count) - 1)
        let idx = index(startIndex, offsetBy: numericCast(offset))
        return self[idx]
    }
}

// MARK: Colors

extension UIColor {
    /// Returns a random solid colour.
    public static var random: UIColor {
        return .init(red: .random, green: .random, blue: .random, alpha: 1)
    }
    
    /// Returns a random colour with a randomized alpha.
    public static var randomWithAlpha: UIColor {
        return random.withAlphaComponent(.random)
    }
}