Check out example codes for "random string swift". It will help you in understanding the concepts better.

Code Example 1

func randomString(of length: Int) -> String {
    let letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
    var s = ""
    for _ in 0 ..< length {
        s.append(letters.randomElement()!)
    }
    return s
}

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