Generate Random String

randomString.swift

/*
generate random string.

possibly contained letters are:
- lower case alphabet
- upper case alphabet
- number

todo: 
    - pass letter kind or letter set
*/
func randomString(length: Int) -> String {
    let alphabetLowerCaseString = "abcdefghijklmnopqrstuvwxyz"
    let alphabetUpperCaseString = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    let numberString = "0123456789"
    let stringSeed = alphabetLowerCaseString + alphabetUpperCaseString + numberString
    
    var result = ""
    for _ in 1...length {
        result += String(stringSeed.randomElement()!)
    }

    return result
}

//8文字のランダムな英数字で生成
let result = randomString(length: 8)
print(result)

// TODO: 引数を取るコマンドラインプログラムにする
// 不正な引数はエラーメッセージを表示する