带有多个正则表达式的PHP preg_replace_callback

Question

Hello guys i have the follow code on php

return preg_replace_callback("#\{gallery: '(.+?)'\}#i", 
    function($i)
    { 
        $oGallery = new Gallery( $i[1] );
        $oGallery->PublicSide();
    }, $string);

Now i want to add the following to it:

Say that that i want to allow the user to choose if he wants to add directories to the gallery so i do:

"#\{gallery: '(.+?)' dir: '(.+?)')\}#i"

so the user has the potion to do: {gallery: 'folder'} or {gallery: 'folder' dir: '1'}

how would i go about doing this in terms of regular expressions so the replacement takes place even if the directory option isnt there? thanks in advance!

Answer 1

Make it optional

"#\{gallery: '(.+?)'(?: dir: '(.+?)')?\}#i"

(?:text) creates a non-capturing group

adding ? after the group makes it optional