%ids;

#loop through lines
#add id to the list
$ids{$my_input_id} = 'anything - doesn't matter';

#end loop
@ids = keys %ids
join(',' @ids);


##</code><code>##

%ids;

#loop through lines
#add id to the list
$ids{$my_input_id} = 'id';

#end loop
@ids = values %ids
join(',' @ids);