How can I generate a random unicode character in Swift?

Question

My current attempts at creating a random unicode character generate have failed with errors such as those mentioned in my other question here. It's obviously not as simple as just generating a random number.

Question: How can I generate a random unicode character in Swift?

It should be possible roughly like this: 1. find a random number from the Unicode range you want the character to be in 2. [get the character corresponding with that number](http://sketchytech.blogspot.com.es/2014/10/playing-with-primitives-characters.html) — Pekka, Aug 22 '15 at 14:57

Tikhonov Aleksandr · Accepted Answer · 2015-08-22T17:07:37.410

3

Unicode Scalar Value

Any Unicode code point except high-surrogate and low-surrogate code points. In other words, the ranges of integers 0 to D7FF and E000 to 10FFFF inclusive.

So, I've made a small code's snippet. See below.

This code works

func randomUnicodeCharacter() -> String {
    let i = arc4random_uniform(1114111)
    return (i > 55295 && i < 57344) ? randomUnicodeCharacter() : String(UnicodeScalar(i))
}
randomUnicodeCharacter()

This code doesn't work!

let N: UInt32 = 65536
let i = arc4random_uniform(N)
var c = String(UnicodeScalar(i))
print(c, appendNewline: false)

I was a little bit confused with this and this. [Maximum value: 65535]

edited Aug 22 '15 at 17:07

answered Aug 22 '15 at 14:59

Tikhonov Aleksandr

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And what exactly is `N` supposed to be? – Vatsal Manot Aug 22 '15 at 15:04
`arc4random_uniform()` will return a uniformly distributed random number less than upper_bound. Therefore, let N: UInt32 = 65536. – Tikhonov Aleksandr Aug 22 '15 at 15:19
This method is faulty. I just encountered this error: `fatal error: high- and low-surrogate code points are not valid Unicode scalar values` – Vatsal Manot Aug 22 '15 at 16:21
I've created a separate question for this error [here](http://stackoverflow.com/questions/32158381/fatal-error-high-and-low-surrogate-code-points-are-not-valid-unicode-scalar-va). – Vatsal Manot Aug 22 '15 at 16:34
@VatsalManot I've found my mistake, one second pls – Tikhonov Aleksandr Aug 22 '15 at 16:56

score 0 · Answer 2 · answered Nov 24 '17 at 12:11

static func randomCharacters(withLength length: Int = 20) -> String {
    let base = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
    var randomString: String = ""

    for _ in 0..<length {
        let randomValue = arc4random_uniform(UInt32(base.characters.count))
        randomString += "\(base[base.index(base.startIndex, offsetBy: Int(randomValue))])"
    }
    return randomString
}

Here you can modify length (Int) and use this for generating random characters.

How can I generate a random unicode character in Swift?

2 Answers2

This code works

This code doesn't work!

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