str_word_count
A simple multibyte-safe case-insensitive string comparison:
<?php
function mb_strcasecmp($str1, $str2, $encoding = null) {
if (null === $encoding) { $encoding = mb_internal_encoding(); }
return strcmp(mb_strtoupper($str1, $encoding), mb_strtoupper($str2, $encoding));
}
?>
Caveat: watch out for edge cases like "ß".
strcasecmp
(PHP 4, PHP 5)
strcasecmp — 二进制安全比较字符串（不区分大小写）
说明
int strcasecmp
( string
$str1
, string $str2
)二进制安全比较字符串（不区分大小写）。
参数
-
str1 -
第一个字符串。
-
str2 -
第二个字符串。
返回值
如果 str1 小于 str2，返回负数；如果 str1 大于 str2，返回正数；二者相等则返回 0。
范例
Example #1 strcasecmp() 范例
<?php
$var1 = "Hello";
$var2 = "hello";
if (strcasecmp($var1, $var2) == 0) {
echo '$var1 is equal to $var2 in a case-insensitive string comparison';
}
?>
参见
- preg_match() - 执行一个正则表达式匹配
- strcmp() - 二进制安全字符串比较
- 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）
- strstr() - 查找字符串的首次出现
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User Contributed Notes
strcasecmp
chris at cmbuckley dot co dot uk
28-Dec-2011 04:59
alvaro at demogracia dot com
29-Jul-2010 05:35
Don't forget this is a single-byte function: in Unicode strings it'll provide incoherent results as soon as both strings differ only in case. There doesn't seem to exist a built-in multi-byte alternative so you need to write your own, taking into account both character encoding and collation.
27-Aug-2002 06:53
The sample above is only true on some platforms that only use a simple 'C' locale, where individual bytes are considered as complete characters that are converted to lowercase before being differentiated.
Other locales (see LC_COLLATE and LC_ALL) use the difference of collation order of characters, where characters may be groups of bytes taken from the input strings, or simply return -1, 0, or 1 as the collation order is not simply defined by comparing individual characters but by more complex rules.
Don't base your code on a specific non null value returned by strcmp() or strcasecmp(): it is not portable. Just consider the sign of the result and be sure to use the correct locale!