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.
strcoll
(PHP 4 >= 4.0.5, PHP 5, PHP 7, PHP 8)
strcoll — 基于区域设置的字符串比较
参数
-
string1 -
第一个字符串。
-
string2 -
第二个字符串。
返回值
如果 string1 小于
string2 返回 < 0；
如果 string1
大于 string2
返回 > 0；如果两者相等，返回 0。
参见
- preg_match() - 执行匹配正则表达式
- strcmp() - 二进制安全字符串比较
- strcasecmp() - 二进制安全比较字符串（不区分大小写）
- substr() - 返回字符串的子串
- stristr() - strstr 函数的忽略大小写版本
- strncasecmp() - 二进制安全比较字符串开头的若干个字符（不区分大小写）
- strncmp() - 二进制安全比较字符串开头的若干个字符
- strstr() - 查找字符串的首次出现
- setlocale() - 设置区域信息
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User Contributed Notes 3 notes
mkroese at eljakim dot nl ¶
5 years ago
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!
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
)
