How to split a string into characters, taking into account accents?

Question

PHP

Hello! Tell me, please, how to split the string character by character into an array, but so that the stresses (for example, one) in the array do not lie as a separate character, but remain with the letter?
Now it works like this, but the accents are considered a separate character.
$arrayLetters = preg_split('//u', $string, NULL, PREG_SPLIT_NO_EMPTY);

Answer 1

You can loop through the array and combine the accent character with the previous character.

$arrayLetters = preg_split('//u', "оди́н", NULL, PREG_SPLIT_NO_EMPTY);
$arrayLettersResult = [];
$stressSym = "́";

foreach ($arrayLetters as $i => $letter) {
    if ($letter == $stressSym) continue;
    if (!empty($arrayLetters[$i + 1]) && $arrayLetters[$i + 1] == $stressSym) {
        $arrayLettersResult[] = $letter . $stressSym;
    } else {
        $arrayLettersResult[] = $letter;
    }
}

var_dump($arrayLettersResult);

/*
array(4) {
  [0]=>
  string(2) "о"
  [1]=>
  string(2) "д"
  [2]=>
  string(4) "и́"
  [3]=>
  string(2) "н"
}
*/

Answer 2

It seems that the usual \s solves the problem)
https://www.phliveregex.com/p/uaC
preg_split('/\s/u', $input_line);