How to sort an array of UTF-8 strings?

Question

I currentyl have no clue on how to sort an array which contains UTF-8 encoded strings in PHP. The array comes from a LDAP server so sorting via a database (would be no probl

Answer 1

I found this following helper function to convert all letters of a string to ASCII letters very helpful here.

function _all_letters_to_ASCII($string) {
  return strtr(utf8_decode($string), 
    utf8_decode('ŠŒŽšœžŸ¥µÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝßàáâãäåæçèéêëìíîïðñòóôõöøùúûüýÿ'),
    'SOZsozYYuAAAAAAACEEEEIIIIDNOOOOOOUUUUYsaaaaaaaceeeeiiiionoooooouuuuyy');
}

After that a simple array_multisort() gives you what you want.

$array = array('Birnen', 'Äpfel', 'Ungetüme', 'Apfel', 'Ungetiere', 'Österreich');
$reference_array = $array;

foreach ($reference_array as $key => &$value) {
  $value = _all_letters_to_ASCII($value);
}
var_dump($reference_array);

array_multisort($reference_array, $array);
var_dump($array);

Of course you can make the helper function fit more advanced needs. But for now, it looks pretty good.

array(6) {
  [0]=> string(6) "Birnen"
  [1]=> string(5) "Apfel"
  [2]=> string(8) "Ungetume"
  [3]=> string(5) "Apfel"
  [4]=> string(9) "Ungetiere"
  [5]=> string(10) "Osterreich"
}

array(6) {
  [0]=> string(5) "Apfel"
  [1]=> string(6) "Äpfel"
  [2]=> string(6) "Birnen"
  [3]=> string(11) "Österreich"
  [4]=> string(9) "Ungetiere"
  [5]=> string(9) "Ungetüme"
}