strcmp
strcoll()'s behavior is sometimes a little bit confusing. It depends on LC_COLLATE in your locale.
<?php
$a = 'a';
$b = 'A';
print strcmp ($a, $b) . "\n"; // prints 1
setlocale (LC_COLLATE, 'C');
print "C: " . strcoll ($a, $b) . "\n"; // prints 1
setlocale (LC_COLLATE, 'de_DE');
print "de_DE: " . strcoll ($a, $b) . "\n"; // prints -2
setlocale (LC_COLLATE, 'de_CH');
print "de_CH: " . strcoll ($a, $b) . "\n"; // prints -2
setlocale (LC_COLLATE, 'en_US');
print "en_US: " . strcoll ($a, $b) . "\n"; // prints -2
?>
This is useful e. g. if want to sort an array by using strcoll:
<?php
$a = array ('a', 'A', 'ä', 'Ä', 'b', 'B');
setlocale (LC_COLLATE, 'C');
usort ($a, 'strcoll');
print_r ($a);
?>
This is like sort($a):
Array
(
[0] => A
[1] => B
[2] => a
[3] => b
[4] => Ä
[5] => ä
)
<?php
setlocale (LC_COLLATE, 'de_DE');
usort ($a, 'strcoll');
print_r ($a)
?>
This is completely different:
Array
(
[0] => a
[1] => A
[2] => ä
[3] => Ä
[4] => b
[5] => B
)
strcoll
(PHP 4 >= 4.0.5, PHP 5)
strcoll — Comparaison de chaînes localisées
Description
int strcoll
( string $str1
, string $str2
)
strcoll() retourne < 0 si str1 est inférieure à str2 ; > 0 si str1 est supérieure à str2 , et 0 si les deux chaînes sont égales. Si la configuration de localisation courante est C ou POSIX, cette fonction est équivalente à strcmp().
Notez que cette comparaison est sensible à la casse, et que, contrairement à strcmp(), elle n'est pas compatible avec les chaînes binaires.
Note: Le paramètre strcoll() a été ajouté dans PHP 4.0.5 mais n'est activé dans la version win32 que depuis PHP 4.2.3.
Voir aussi preg_match(), strcmp(), strcasecmp(), substr(), stristr(), strncasecmp(), strncmp(), strstr() et setlocale().
add a note
User Contributed Notesstrcoll
sakkarinlaohawisut15 at hotmail dot com
22-Mar-2003 11:31
22-Mar-2003 11:31
27-Aug-2002 07:05
Note that some platforms implement strcmp() and strcasecmp() according to the current locale when strings are not binary equal, so that strcmp() and strcoll() will return the same value! This depends on how the PHP strcmp() function is compiled (i.e. if it uses the platform specific strcmp() found in its standard library!).
In that case, the only difference between strcoll() and strcmp() is that strcoll() may return 0 for distinct strings(i.e. consider strings are equal) while strcmp() will differentiate them if they have distinct binary encoding! This typically occurs on Asian systems.
What you can be sure is that strcmp() will always differentiate strings that are encoded differently, but the relative order may still use the current locale setting for collation order!