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 — Confronto tra stringhe basato sulle impostazioni locali
Descrizione
int strcoll
( string $str1
, string $str2
)
Restituisce < 0 se str1 è minore di str2 ; > 0 se str1 è maggiore di str2 , e 0 se sono uguali. strcoll() utilizza le impostazioni locali per il confronto. Se le impostazioni locali sono conformi al C o a POSIX, allora la funzione è equivalente a strcmp().
Attenzione. questo confronto distingue tra maiuscole e minuscole, e, diversamente da strcmp() non è affidabile con i dati binari.
Nota: strcoll() è stato aggiunto in PHP 4.0.5, ma sui sistemi win32 non è stato abilitato fino alla versione 4.2.3.
Vedere anche ereg(), strcmp(), strcasecmp(), substr(), stristr(), strncasecmp(), strncmp(), strstr() e setlocale().
add a note
User Contributed Notesstrcoll
sakkarinlaohawisut15 at hotmail dot com
23-Mar-2003 03:31
23-Mar-2003 03:31
27-Aug-2002 10:05
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!