Generate random alphanumeric string in Swift

Question

How can I generate a random alphanumeric string in Swift?

Answer 1

UPDATED 2019.

In the unusual case that

performance matters.

Here is an extremely clear function that caches:

func randomNameString(length: Int = 7)->String{
    
    enum s {
        static let c = Array("abcdefghjklmnpqrstuvwxyz12345789")
        static let k = UInt32(c.count)
    }
    
    var result = [Character](repeating: "-", count: length)
    
    for i in 0..

This is for when you have a fixed, known character set.

Handy tip:

Note that "abcdefghjklmnpqrstuvwxyz12345789" avoids 'bad' characters

There is no 0, o, O, i, etc ... the characters humans often confuse.

This is often done for booking codes and similar codes which human customers will use.