Wondering why your preg_replace fails, even if you have used preg_quote?Try adding the delimiter / - preg_quote($string, '/');
(PHP 4, PHP 5, PHP 7, PHP 8)
preg_quote — 转义正则表达式字符
preg_quote()需要参数 str 并向其中
每个正则表达式语法中的字符前增加一个反斜线。 这通常用于你有一些运行时字符串
需要作为正则表达式进行匹配的时候。
正则表达式特殊字符有：
. \ + * ? [ ^ ] $ ( ) { } = ! < > | : - #
注意 / 不是正则表达式特殊字符。
注意:
注意：preg_quote() 的应用场景不是用于 preg_replace() 的 $replacement 字符串参数。
str输入字符串
delimiter
如果指定了可选参数 delimiter，它也会被转义。这通常用于
转义PCRE函数使用的分隔符。 / 是最常见的分隔符。
返回转义后的字符串。
| 版本 | 说明 |
|---|---|
| 7.3.0 |
字符 # 被增加为需要转义的。
|
| 7.2.0 |
delimiter 现在可为 null。
|
示例 #1 preg_quote()示例
<?php
$keywords = '$40 for a g3/400';
$keywords = preg_quote($keywords, '/');
echo $keywords; // 返回 \$40 for a g3\/400
?>
示例 #2 将文本中的单词替换为斜体
<?php
//在这个例子中，preg_quote($word) 用于保持星号原文涵义，使其不使用正则表达式中的特殊语义。
$textbody = "This book is *very* difficult to find.";
$word = "*very*";
$textbody = preg_replace ("/" . preg_quote($word, '/') . "/",
"<i>" . $word . "</i>",
$textbody);
?>注意: 此函数可安全用于二进制对象。
Wondering why your preg_replace fails, even if you have used preg_quote?Try adding the delimiter / - preg_quote($string, '/');To escape characters with special meaning, like: .-[]() and so on, use \Q and \E.For example:<?php echo ( preg_match('/^'.( $myvar = 'te.t' ).'$/i', 'test') ? 'match' : 'nomatch' ); ?>Will result in: matchBut:<?php echo ( preg_match('/^\Q'.( $myvar = 'te.t' ).'\E$/i', 'test') ? 'match' : 'nomatch' ); ?>Will result in: nomatchIt should be noted that the forward slash is not escaped. Since many regexes are surrounded by forward slashes, if you have one in your regex as text you must escape it yourself otherwise it'll terminat the regex.List of specials is incomplete:--- sample code ---$specials = '.\+*?[^]$(){}=!<>|:-';for ($i = 0; $i <= 255; $i++) { if (chr($i) !== preg_quote(chr($i))) { printf("Character 0x%02x quoted%s\n", $i, (strpos($specials, chr($i)) === FALSE) ? ' (+)' : ''); } /* if */} /* for */--- sample code ------ output ---Character 0x00 quoted (+)Character 0x21 quotedCharacter 0x24 quotedCharacter 0x28 quotedCharacter 0x29 quotedCharacter 0x2a quotedCharacter 0x2b quotedCharacter 0x2d quotedCharacter 0x2e quotedCharacter 0x3a quotedCharacter 0x3c quotedCharacter 0x3d quotedCharacter 0x3e quotedCharacter 0x3f quotedCharacter 0x5b quotedCharacter 0x5c quotedCharacter 0x5d quotedCharacter 0x5e quotedCharacter 0x7b quotedCharacter 0x7c quotedCharacter 0x7d quoted--- output ---I discovered that, in addition to escaping the special regular expression characters, preg_quote() encodes the NUL byte to its octal representation:<?phpvar_dump(preg_quote("\0"));?>Output:string(4) "\000"To have a higher level control of what your pattern looks like, try T-Regx:Pattern::inject('This is (my|our) pattern: @', [$_GET['name']]);