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

Eventually this problem cannot be solved in a simple way without using recoded strings (UTF-8 → Windows-1252 or ISO-8859-1) as suggested by ΤΖΩΤΖΙΟΥ due to an obvious PHP bug as discovered by Huppie. To summarize the problem, I created the following code snippet which clearly demonstrates that the problem is the strcoll() function when using the 65001 Windows-UTF-8-codepage.

function traceStrColl($a, $b) {
    $outValue=strcoll($a, $b);
    echo "$a $b $outValue\r\n";
    return $outValue;
}

$locale=(defined('PHP_OS') && stristr(PHP_OS, 'win')) ? 'German_Germany.65001' : 'de_DE.utf8';

$string="ABCDEFGHIJKLMNOPQRSTUVWXYZÄÖÜabcdefghijklmnopqrstuvwxyzäöüß";
$array=array();
for ($i=0; $i

The result is:

string(20) "German_Germany.65001"
a B 2147483647
[...]
array(59) {
  [0]=>
  string(1) "c"
  [1]=>
  string(1) "B"
  [2]=>
  string(1) "s"
  [3]=>
  string(1) "C"
  [4]=>
  string(1) "k"
  [5]=>
  string(1) "D"
  [6]=>
  string(2) "ä"
  [7]=>
  string(1) "E"
  [8]=>
  string(1) "g"
  [...]

The same snippet works on a Linux machine without any problems producing the following output:

string(10) "de_DE.utf8"
a B -1
[...]
array(59) {
  [0]=>
  string(1) "a"
  [1]=>
  string(1) "A"
  [2]=>
  string(2) "ä"
  [3]=>
  string(2) "Ä"
  [4]=>
  string(1) "b"
  [5]=>
  string(1) "B"
  [6]=>
  string(1) "c"
  [7]=>
  string(1) "C"
  [...]

The snippet also works when using Windows-1252 (ISO-8859-1) encoded strings (of course the mb_* encodings and the locale must be changed then).

I filed a bug report on bugs.php.net: Bug #46165 strcoll() does not work with UTF-8 strings on Windows. If you experience the same problem, you can give your feedback to the PHP team on the bug-report page (two other, probably related, bugs have been classified as bogus - I don't think that this bug is bogus ;-).

Thanks to all of you.