How to uppercase Turkish "i"?

Question

In Turkish, there are two i

Dotless: ı, I
Dotted: i, İ

PROBLEM: Every time I uppercase an i, I get an I.

I want to get an İ (only in Turkish) when I uppercase an i, and an I when I uppercase an ı.

I have a function to do it

@objc public static func uppercaseTurkishString(_ string: String) -> String {
    return String(string.map { (char) -> Character in
        if char == "i" {
            return "İ"
        } else {
            return Character(String(char).uppercased())
        }
    })
}

But I have to check if the language is Turkish every time I use it, and doing it for every single string in the app is a very hard job.

Is there an easier way to do it?

There is a strange difference, if you do `let turckishI = "Dotless: ı, I Dotted: i, İ"`, then `turckishI.localizedLowercase`, you'll see that the rendered lowercase i (the last one) is different from yours. But there is also locale uppercase. — Larme, Sep 19 '18 at 09:20
Related: [Uppercase All String According to Locale - Swift](https://stackoverflow.com/questions/32715323/uppercase-all-string-according-to-locale-swift) — Martin R, Sep 19 '18 at 09:25

score 7 · Accepted Answer · edited Sep 20 '18 at 06:39

The problem lies in the fact that the uppercased() function doesn't care about Locales and the small dotted i looks like the normal English i. You should use localizedUppercase, which will use the Turkish Locale for Turkish users (or uppercased(with: Locale(identifier: "tr_TR"), in case you want this to be done for all users of your app regardless of their locale settings, but I wouldn't recommend that).

Moreover, there's no need to do the upper casing character-by-character, you can simply do it on the full String.

@objc public static func uppercaseTurkishString(_ string: String) -> String {
    return string.localizedUppercase
}

score 1 · Answer 2 · edited Sep 19 '18 at 09:25

1

Foundation developers already thought about it, and that's exactly why there is uppercased(with: Locale?):

"i".uppercased(with: Locale(identifier: "tr_TR")) // returns "İ"
"i".uppercased(with: Locale(identifier: "en_US")) // returns "I"
"ı".uppercased(with: Locale(identifier: "tr_TR")) // returns "I"

edited Sep 19 '18 at 09:25

Ashley Mills

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answered Sep 19 '18 at 09:19

user28434'mstep

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How to uppercase Turkish "i"?

2 Answers2