strcoll

(PHP 4 >= 4.0.5, PHP 5, PHP 7, PHP 8)

strcoll — Comparaison de chaînes localisées

Description

strcoll(string $string1, string $string2): int

Notez que cette comparaison est sensible à la casse, et que, contrairement à strcmp(), elle n'est pas compatible avec les chaînes binaires.

strcoll() utilise les locales courantes pour effectuer la comparaison. Si la locale courante est C ou POSIX, cette fonction est alors équivalente à la fonction strcmp().

Liste de paramètres

string1: La première chaîne.
string2: La seconde chaîne.

Valeurs de retour

Retourne < 0 si string1 est inférieure à string2; > 0 si string1 est supérieure à string2, et 0 si les deux chaînes sont égales.

Voir aussi

preg_match() - Effectue une recherche de correspondance avec une expression rationnelle standard
strcmp() - Comparaison binaire de chaînes
strcasecmp() - Comparaison insensible à la casse de chaînes binaires
substr() - Retourne un segment de chaîne
stristr() - Version insensible à la casse de strstr
strncasecmp() - Compare en binaire des chaînes de caractères
strncmp() - Comparaison binaire des n premiers caractères
strstr() - Trouve la première occurrence dans une chaîne
setlocale() - Modifie les informations de localisation

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User Contributed Notes 3 notes

down

Anonymous ¶

22 years ago

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!

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mkroese at eljakim dot nl ¶

5 years ago

You should not rely on this function to properly compare localized strings.

<?php
$a = "Österreich";
$b = "Oesterreich";
$z = "Zeta";

echo setlocale(LC_ALL, 0) . PHP_EOL; // (on my mac: C/en_US.UTF-8/C/C/C/C)
echo strcoll($a, $b) . PHP_EOL; // 116
echo strcoll($b, $a) . PHP_EOL; // -116
echo strcoll($a, $z) . PHP_EOL; // 105

echo setlocale(LC_ALL, "de_DE") . PHP_EOL; // de_DE
echo strcoll($a, $b) . PHP_EOL; // 135
echo strcoll($b, $a) . PHP_EOL; // -135
echo strcoll($a, $z) . PHP_EOL; // 124

$collator = new Collator("de_DE");
echo $collator->compare($a, $b); // 1
echo $collator->compare($b, $a); // -1
echo $collator->compare($a, $z); // -1
?>

Using the Collator (from the intl module) you will get the expected result for e.g. sorting such that the string "Österreich" will rank higher than "Zeta", but after "Oesterreich".

strcoll's output will differ per platform, locale and used c library, while the Collator will give more stable results on different platforms.

down

-1

sakkarinlaohawisut15 at hotmail dot com ¶

21 years ago

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', '?', '?', '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] => ?
    [5] => ?
 )

<?php

 setlocale (LC_COLLATE, 'de_DE');
usort ($a, 'strcoll');
 print_r ($a)

?>
 
This is completely different:
 Array
 (
    [0] => a
    [1] => A
    [2] => ?
    [3] => ?
    [4] => b
  [5] => B
 )

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