Displaying post ID within shortcode php in template

Have re-posted this question in the themes & templating section as I realised this maybe wasn’t the best place for it. Apologies for the double post.

Here is the other thread: https://www.ads-software.com/support/topic/displaying-post-id-within-shortcode-php-in-template-1?replies=1

[please stay with your current topic – it does not matter too much in what sub forum you are posting. other, duplicate thread removed]

I found the answer to this, I think at first I was not searching for the right terms, but when I searched php inside echo things made more sense (thanks to this post – https://www.ads-software.com/support/topic/php-inside-php-echo)

Posting the solution here in case anyone is interested:

<?php echo do_shortcode('[hide-this-part]
this is where I put my html...blablabla...
'. the_id() .'
[/hide-this-part]'); ?>

I also had trouble having the post ID generated as part of the item name of a Paypal button WITHIN the shortcode area, and that worked by using:

. get_the_ID() .

instead of . the_id() .

Will mark this as resolved now.