How do I retrieve the record ID?

Hi,

I am working with a modified template of the pdb_list.
Whilst iterating through records, I need to create an array populated by a list of the record IDs.
Can this be done? Or is there perhaps another way anyone can suggest?

I am currently using this

array_push($results_pending, $this->record_id);

but clearly is doesnt work, but I cant find anything else online.

Any help would be greatly appreciated ??

https://www.ads-software.com/extend/plugins/participants-database/