substr_replace() when used with special charactors (äöå) replaces with a? [duplicate] - php

Question

I'm trying to do accented character replacement in PHP but get funky results, my guess being because i'm using a UTF-8 string and str_replace can't properly handle multi-byte strings..
$accents_search = array('á','à','â','ã','ª','ä','å','Á','À','Â','Ã','Ä','é','è',
'ê','ë','É','È','Ê','Ë','í','ì','î','ï','Í','Ì','Î','Ï','œ','ò','ó','ô','õ','º','ø',
'Ø','Ó','Ò','Ô','Õ','ú','ù','û','Ú','Ù','Û','ç','Ç','Ñ','ñ');
$accents_replace = array('a','a','a','a','a','a','a','A','A','A','A','A','e','e',
'e','e','E','E','E','E','i','i','i','i','I','I','I','I','oe','o','o','o','o','o','o',
'O','O','O','O','O','u','u','u','U','U','U','c','C','N','n');
$str = str_replace($accents_search, $accents_replace, $str);
Results I get:
Ørjan Nilsen -> �orjan Nilsen
Expected Result:
Ørjan Nilsen -> Orjan Nilsen
Edit: I've got my internal character handler set to UTF-8 (according to mb_internal_encoding()), also the value of $str is UTF-8, so from what I can tell, all the strings involved are UTF-8. Does str_replace() detect char sets and use them properly?

Answer 1

According to php documentation str_replace function is binary-safe, which means that it can handle UTF-8 encoded text without any data loss.

Answer 2

Looks like the string was not replaced because your input encoding and the file encoding mismatch.

Answer 3

It's possible to remove diacritics using Unicode normalization form D (NFD) and Unicode character properties.
NFD converts something like the "ü" umlaut from "LATIN SMALL LETTER U WITH DIAERESIS" (which is a letter) to "LATIN SMALL LETTER U" (letter) and "COMBINING DIAERESIS" (not a letter).
header('Content-Type: text/plain; charset=utf-8');
$test = implode('', array('á','à','â','ã','ª','ä','å','Á','À','Â','Ã','Ä','é','è',
'ê','ë','É','È','Ê','Ë','í','ì','î','ï','Í','Ì','Î','Ï','œ','ò','ó','ô','õ','º','ø',
'Ø','Ó','Ò','Ô','Õ','ú','ù','û','Ú','Ù','Û','ç','Ç','Ñ','ñ'));
$test = Normalizer::normalize($test, Normalizer::FORM_D);
// Remove everything that's not a "letter" or a space (e.g. diacritics)
// (see http://de2.php.net/manual/en/regexp.reference.unicode.php)
$pattern = '/[^\pL ]/u';
echo preg_replace($pattern, '', $test);
Output:
aaaaªaaAAAAAeeeeEEEEiiiiIIIIœooooºøØOOOOuuuUUUcCNn
The Normalizer class is part of the PECL intl package. (The algorithm itself isn't very complicated but needs to load a lot of character mappings afaik. I wrote a PHP implementation a while ago.)
(I'm adding this two months late because I think it's a nice technique that's not known widely enough.)

Answer 4

Try this function definition:
if (!function_exists('mb_str_replace')) {
function mb_str_replace($search, $replace, $subject) {
if (is_array($subject)) {
foreach ($subject as $key => $val) {
$subject[$key] = mb_str_replace((string)$search, $replace, $subject[$key]);
}
return $subject;
}
$pattern = '/(?:'.implode('|', array_map(create_function('$match', 'return preg_quote($match[0], "/");'), (array)$search)).')/u';
if (is_array($search)) {
if (is_array($replace)) {
$len = min(count($search), count($replace));
$table = array_combine(array_slice($search, 0, $len), array_slice($replace, 0, $len));
$f = create_function('$match', '$table = '.var_export($table, true).'; return array_key_exists($match[0], $table) ? $table[$match[0]] : $match[0];');
$subject = preg_replace_callback($pattern, $f, $subject);
return $subject;
}
}
$subject = preg_replace($pattern, (string)$replace, $subject);
return $subject;
}
}