PHP：正则表达式将所有内容替换为字符串/ HTML标记

Question

I have the below text but want the quote bit removed from the string, I'm using the below regex but it gives me the below error.

Text Example 1

<p>[quote]</p>
<p>[quote]</p>
<p>inner quote text</p>
<p>[/quote]</p>
<p>outer quote text</p>
<p>[/quote]</p>
<p>This is a test.</p>

Text Example 2

<p>[quote][quote]</p>
<p>inner quote text</p>
<p>[/quote]</p>
<p>outer quote text</p>
<p>[/quote]</p>
<p>This is a test.</p>

Expected Text

<p>This is a test.</p>

Regex

preg_replace('/<p>\[quote\][\s\S]+?<p>\[\/quote\]<\/p>/', '', $string);

Error

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

I've had a look at Deleting text between two strings in php using preg_replace which has helped but I haven't been able to figure it out, any help greatly appreciated.

Answer 1

The reason you're getting the error is because you've not escaped an opening [ character in your regular expression. Please see the [ I have marked below:

preg_replace('/\<p\>\[quote\]\<\/p\>[\s\S]+?\<p\>[\/quote\]\<\/p\>/', '', $string);
                                                 ^

This has resulted in starting a character class that has not been closed. You should simply escape this opening brace like this:

preg_replace('/\<p\>\[quote\]\<\/p\>[\s\S]+?\<p\>\[\/quote\]\<\/p\>/', '', $string);

Answer 2

Extracting text from HTML is tricky, so the best option is to use a library like Html2Text. It was built specifically for this purpose.

https://github.com/mtibben/html2text

Install using composer:

composer require html2text/html2text Basic usage:

$html = new \Html2Text\Html2Text('<p>[quote</p>test piece of text<p>[/quote]</p>This is a test.');

echo $html->getText();  // test piece of text This is a test.

OR you can use simply the function PHP strip_tags

string strip_tags ( string $str [, string $allowable_tags ] )

http://php.net/strip_tags

echo str_replace("[/quote]","",str_replace("[quote","",strip_tags("<p>
[quote</p>
test piece of text
<p>[/quote]</p>
This is a test.")));