Check if two parts of a string are the same with regex (PHP)?

Question

using a regular expression in PHP with preg_replace_callback how can I check if two parts of the pattern are the same?

preg_replace_callback('/Blah: (.*?), BLah Blah (.+?), (**String Here Must Be Same as First Match**)/s', create_function(), $subject);

Thanks, Matt

casablanca · Accepted Answer · 2010-09-07 16:33:32Z

4

You can use a backreference:

/Blah: (.*?), BLah Blah (.+?), \1/s

\1 here denotes the first matched group.

answered Sep 7, 2010 at 16:33

casablanca

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5 Comments

Best place to go for more information on them is regular-expressions.info/brackets.html

Thanks for posting the link, I thought of adding a reference myself. :)

I was going to post an answer, but a comment reference will do. :)

Excellent! Thanks Guys! I've been trying to do this for the last 6 months lol!

You're welcome. Why did you wait 6 months to post in the first place? :)