How to use preg_match to extract data?

Question

I am pretty new to the use of preg_match. Searched a lot for an answer before posting this question. Found a lot of posts to get data based on youtube ID etc. But nothing as

Answer 1

Your regular expression:

preg_match('/^\[\#([0-9]+)\].+/i', $string, $array);

Answer 2

That's a way you could do it:

<?php
$subject = "[#1234] Subject";
$pattern = '/^\[\#([0-9]+)/';
preg_match($pattern, $subject, $matches);

echo $matches[1]; // 1234
?>

Answer 3

To get only the integer you can use subpatterns http://php.net/manual/en/regexp.reference.subpatterns.php

 $string="[#1234] Subject";
 $pattern="/\[#(?P<my_id>\d+)](.*?)/s";
 preg_match($pattern,$string,$match);
 echo $match['my_id'];

Answer 4

One solution is:

\[#(\d+)\]

This matches the left square bracket and pound sign [#, then captures one or more digits, then the closing right square bracket ].

You would use it like:

preg_match( '/\[#(\d+)\]/', '[#1234] Subject', $matches);
echo $matches[1]; // 1234

You can see it working in this demo.

Answer 5

You can try this:

preg_match('~(?<=\[#)\d+(?=])~', $txt, $match);

(?<=..) is a lookbehind (only a check)

(?=..) is a lookahead