Question

I have some strings like max_length[:num:]where :num: can be any number ie(max_length[50] or max_length[100] etc).

What will be the preg_match code for such strings in PHP?

Answer 1

Try this:

'/max_length\[(\d+)\]/'

\d+ matches one or more digits.

If your string must contain only this, use this one instead:

'/^max_length\[(\d+)\]$/'

You can use it like this:

$string = 'max_length[123]';
if (preg_match('/max_length\[(\d+)\]/', $string, $match)) {
    $number = $match[1];
}

Try it here: http://ideone.com/a9Cux