Question

I’ve always had a difficult time with regular expressions. I’ve searched for help with this, but I can’t quite find what I’m looking for.

I have blocks of text that follow this pattern:

[php]
… any type of code sample here
[/php]

I need to:

• check for the square brackets, which can contain any number of 20-30 programming language names (php, ruby, etc.).
• need to grab all code in between the opening and closing bracket.

I have worked out the following regular expression:

#\[([a-z]+)\]([^\[/]*)\[/([a-z]+)\]#i

Which matches everything pretty well. However, it breaks when the code sample contains square brackets. How do I modify it so that any character between those opening/closing braces will be matched for later use?

Answer 1

This is the regex you want. It matches where the tags are even too, so a php tag will only end a php tag.

/\[(\w+)\](.*?)\[\/\1\]/s

Or if you wanted to explicitly match the tags you could use…

$langs = array('php', 'python', ...); 

$langs = implode('|', array_map('preg_quote', $langs));

preg_match_all('/\[(' . $langs . ')\](.*?)\[\/\1\]/s', $str, $matches);