Question

I can’t seem to figure out the regular expression to match any string that’s in the format

**(anything that's not **)**

I tried doing this in php

$str = "** hello world * hello **";
$str = preg_replace('/\*\*(([^\*][^\*]+))\*\*/s','<strong>$1</strong>',$str);

but no string replacement was done.

Answer 1

You can use an assertion ?! paired with a character-wise . placeholder:

= preg_replace('/\*\*(((?!\*\*).)+)\*\*/s',

This basically means to match any number of anythings (.)+, but the . can never occupy the place of a \*\*