strcoll

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

strcoll — Comparación de cadenas basada en la localidad

Descripción

strcoll(string $str1, string $str2): int

Note que esta comparación es sensible a mayúsculas y minúsculas, y a diferencia de strcmp(), esta función no es segura con material binario.

strcoll() usa la localidad actual para realizar las comparaciones. Si la localidad actual es C o POSIX, esta función es equivalente a strcmp().

Parámetros

str1: La primera cadena.
str2: La segunda cadena.

Valores devueltos

Devuelve < 0 si str1 es menor que str2; > 0 si str1 es mayor que str2, y 0 si son equivalentes.

Historial de cambios

Versión	Descripción
4.2.3	Esta función trabaja ahora en win32.

Ver también

preg_match() - Realiza una comparación con una expresión regular
strcmp() - Comparación de string segura a nivel binario
strcasecmp() - Comparación de string segura a nivel binario e insensible a mayúsculas y minúsculas
substr() - Devuelve parte de una cadena
stristr() - strstr insensible a mayúsculas y minúsculas
strncasecmp() - Comparación de los primeros n caracteres de cadenas, segura con material binario e insensible a mayúsculas y minúsculas
strncmp() - Comparación segura a nivel binario de los primeros n caracteres entre strings
strstr() - Encuentra la primera aparición de un string
setlocale() - Establecer la información del localismo

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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!

down

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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