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I've been reading user comments for the strtoupper() PHP function and there doesn't seem to a consensus on how to do the conversion for non-Enlgish strings. I mean people offer localized solutions and stuff, but shouldn't there be a uniform way to convert a string to all upper (or all lower) case letters?

So my question is, say, if I have a UTF-8 encoded string (in some unknown locale) how do I convert it to all upper/lower letters in PHP?

ahmd0
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2 Answers2

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You want to use mb_strtoupper.

$str = "Τάχιστη αλώπηξ βαφής ψημένη γη, δρασκελίζει υπέρ νωθρού κυνός";
$str = mb_strtoupper($str, "UTF-8");
echo $str; // Prints ΤΆΧΙΣΤΗ ΑΛΏΠΗΞ ΒΑΦΉΣ ΨΗΜΈΝΗ ΓΗ, ΔΡΑΣΚΕΛΊΖΕΙ ΥΠΈΡ ΝΩΘΡΟΎ ΚΥΝΌΣ

PHP.net states:

By contrast to the standard case folding functions such as strtolower() and strtoupper(), case folding is performed on the basis of the Unicode character properties. Thus the behaviour of this function is not affected by locale settings and it can convert any characters that have 'alphabetic' property, such as A-umlaut (Ä).

Kelly
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0

Have you tried this? I'm no linguist, but I wouldn't assume that all languages have a lower / upper case split.

Robin
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    At least not for every character. For example `ß` has no uppercase :) – KingCrunch May 11 '11 at 20:09
  • every language ? what about chinese or arabic. In arabic you have a three version for each character, not all characters have corresponding version in all three groups, in greek there is one letter that has also initial (that is our uppercase) normal and final version – rsk82 Jul 25 '11 at 12:08
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    "have you tried" for a years old answer while the same function suggestion is already part of the better worded and accepted answer (and earlier) - If we find the time to clean this up, would be great. – hakre Jan 23 '16 at 20:23