For the shortcode I am using, the developer of the plugin only added the ability to output content via the shortcode. So the shortcode is all I have to work with.

Here is the default shortcode which does work:

echo do_shortcode("[theplugin_user_data user_id='8']");

With this code, it will output the data for the user with user id of "8".

I am putting this in the comments section to pull the data. I am using the default wordpress comments system, no plugins or external comments system (the plugin I am pulling data from doesn't have anything to do with comments).

So basically I need to fetch the user id of the current comment author, and after fetching their id I need to insert it dynamically into the shortcode.

Here is an idea of what I can come up with but I don't know how to make it work.

echo do_shortcode("[theplugin_user_data user_id='" . phpcodehere . "']");

So how can I get the current commenter's user id and insert it into the shortcode shown above?