PHP: strlen - Wrong result for Diacritics, Accents and Unicode Characters
Question by Guest | 2016-06-13 at 15:40
I am using the PHP function strlen() to determine and check the length of some user input. Unfortunately, this function is only working for strings, that are not containing any diacritics, accents, umlauts or other Unicode characters.
echo strlen("abc"); // result: 3
echo strlen("äbc"); // result: 4In my script, I need the exact number of characters and I would like to have the result "3" for both, "abc" as well as "äbc".
Is this a PHP bug or what can I do to solve this?
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A single character can be encoded in more than one byte depending on the used character encoding. A typical example is the UTF-8 encoding that is used for most websites. In this encoding, characters like a-z encoded with one byte, characters like ä, ü or ö with multiple bytes.
The function strlen() is only counting the number of bytes, it is not taking into account the meaning or encoding of the bytes. Therefore, you should better use the function mb_strlen() instead of strlen():
echo mb_strlen("abc", "utf-8"); // result: 3 echo mb_strlen("äbc", "utf-8"); // result: 3Apart from strlen(), the multibyte function mb_strlen() is considering the coding and the resulting character length.
As a first parameter, you can pass the string you want to check, the encoding can be passed as the second parameter. If your website is UTF-8 encoded like most websites, you have to specify "utf-8" at this point.
2016-06-13 at 23:16