Vfrdtyky

I have this preg_replace

preg_replace('/[link=(.*?)](.*?)[/link]/', '<a href="1">2</a>', $input);

For this data

$input = "[link=xxx]xxx[/link] [link=yyy][/link]"

it produces:

<a href="xxx">xxx</a> <a href="yyy"></a>

However, I would like the result to be

<a href="xxx">xxx</a> <a href="yyy">yyy</a>

Can I somehow use 2 and if the string is empty, use 1 instead in preg_replace replacement? I dont want to use callback version of preg_replace.

As @mario pointed out, you need to use preg_replace_callback for a problem like this. Inside the callback you can check if there is a second group match, and if not, repeat the first match inside the <a> element:

$input = "[link=xxx]xxx[/link] [link=yyy][/link]";

echo preg_replace_callback('/[link=(.*?)](.*?)[/link]/', 

                           function ($m) { 

                               return "<a href="$m[1]">" . (strlen($m[2]) ? $m[2] : $m[1]) . '</a>'; 

                           },

                           $input);

Output

<a href="xxx">xxx</a> <a href="yyy">yyy</a>

Demo on 3v4l.org