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
$a = array ('a', 'A', '', '', 'b', 'B');
setlocale (LC_COLLATE, 'C');
usort ($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
)
strcoll
(PHP 4 >= 4.0.5, PHP 5)
strcoll — ロケールに基づく文字列比較
説明
int strcoll
( string $str1
, string $str2
)
この比較は大文字小文字を区別すること、そして、 strcmp() とは異なり、 バイナリセーフではないことに注意してください。
strcoll() は比較を行う際に現在のロケールを使用します。 ロケールが C または POSIX の場合、この関数は strcmp() と等価です。
パラメータ
- str1
-
最初の文字列。
- str2
-
次の文字列。
返り値
str1 が str2 より小さい場合に 0 未満の値、str1 が str2 より大きい場合に 0 より大きな値、 両者が等しい場合に 0 を返します。
変更履歴
| バージョン | 説明 |
|---|---|
| 4.2.3 | この関数が win32 でも動作するようになりました。 |
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!