PHP: Iterate UTF-8 String Character by Character

Indeed, most of the normal PHP functions are not capable of multibyte strings.

But you can do it this way:

$s = 'abcäüö';
$arr = preg_split('//u', $s, -1, PREG_SPLIT_NO_EMPTY);
 
foreach ($arr as $v) {
  echo $v;
}

Using preg_split, you are splitting the string into a single characters and you store them in an array. After that, you can easily loop through the array to access your individual characters.

By the way, we are using the modifier "u" so that the string is treated as UTF-8.
2014-03-13 at 23:32

I think the most efficient way to process each character in a UTF-8 (or similarly encoded) string would be to work through the string using mb_substr. In each iteration of the processing loop, mb_substr would be called twice (to find the next character and the remaining string). It would pass only the remaining string to the next iteration. This way, the main overhead in each iteration would be finding the next character (done twice), which takes only one to five or so operations, depending on the byte length of the character.

If this description is not clear, let me know and I'll provide a working PHP function.
2016-02-29 at 23:56