strcasecmp
(PHP 4, PHP 5)
strcasecmp — 二进制安全比较字符串（不区分大小写）
说明
$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 < 0；
如果 str1
大于 str2
返回 > 0；如果两者相等，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 $var2 in a case-insensitive string comparison' ;
}
?> 参见
- strcmp() - 二进制安全字符串比较
- preg_match() - 执行一个正则表达式匹配
- substr_compare() - 二进制安全比较字符串（从偏移位置比较指定长度）
- strncasecmp() - 二进制安全比较字符串开头的若干个字符（不区分大小写）
- stristr() - strstr 函数的忽略大小写版本
- substr() - 返回字符串的子串
用户评论:
[#1] chris at cmbuckley dot co dot uk [2011-12-28 16:59:18]
A simple multibyte-safe case-insensitive string comparison:
<?php
function mb_strcasecmp($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 "?".
[#2] alvaro at demogracia dot com [2010-07-29 05:35:06]
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.
[#3] [2002-08-27 06:53:49]
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!