PHP 5.5.17 is available

strcasecmp

(PHP 4, PHP 5)

strcasecmp大文字小文字を区別しないバイナリセーフな文字列比較を行う

説明

int strcasecmp ( string $str1 , string $str2 )

大文字小文字を区別しないバイナリセーフな文字列比較を行います。

パラメータ

str1

最初の文字列。

str2

次の文字列。

返り値

str1str2 より小さい場合は負、str1str2 より大きい場合は正、等しい場合は 0 を返します。

例1 strcasecmp() の例

<?php
$var1 
"Hello";
$var2 "hello";
if (
strcasecmp($var1$var2) == 0) {
    echo 
'$var1 is equal to $var2 in a case-insensitive string comparison';
}
?>

参考

  • strcmp() - バイナリセーフな文字列比較
  • preg_match() - 正規表現によるマッチングを行う
  • substr_compare() - 指定した位置から指定した長さの 2 つの文字列について、バイナリ対応で比較する
  • strncasecmp() - バイナリセーフで大文字小文字を区別しない文字列比較を、最初の n 文字について行う
  • stristr() - 大文字小文字を区別しない strstr
  • substr() - 文字列の一部分を返す

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User Contributed Notes 3 notes

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10
Anonymous
12 years ago
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!
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6
chris at cmbuckley dot co dot uk
2 years ago
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".
up
1
alvaro at demogracia dot com
4 years ago
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.
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