Warning: preg_replace(): Compilation failed: missing terminating ] for character class at offset 10 in

Warning: preg_replace(): Compilation failed: missing terminating ] for character class at offset 10 in

一、总结

1、[是正则中特殊字符，需要用\反斜杠转义

二、Warning: preg_replace(): Compilation failed: missing terminating ] for character class at offset 10 in

1、问题

I've got a series of .txt files that I'm reading in a for loop. And I've placed a token in some of the text files in the form [widget_]

So, the entire contents of the text file might be [widget_search] for example. And another text file might contain the content [widget_recent-posts]. Others might just have html formatted text and not have the token at all.

In the for loop, I'm doing a preg_match to see if the text file is one in which the contents matches my token pattern. And if a match, I'm executing some conditional code.

However, I'm getting an error when I run a trace test to see if there's a match.

The error is:

Warning: preg_match() [function.preg-match]: Compilation failed: missing terminating ] for character class at offset 8 in C:\xampplite\htdocs\test\wp-content\plugins\widget-test\widget-test.php on line 227

And here's the code at line 227:

if (preg_match("/[widget_/i",$widget_text)) {//do something}

2、解答

You should escape the [ character like this:

if (preg_match("/\[widget_/i",$widget_text)) {//do something}

3、相似错误

$start="/^<![CDATA[/";
$v=preg_replace($start,"",$v);

三、测试题-简答题

1、正则中常见的需要转义的特殊字符？

解答：\. \/   \[  \(  \(  \d