Thanks, I think I'm clear now. I guess (map(str, stn_list)) was all about how to make a string starting with integers. I picked that up and began using it without realising it was over catering for a list already containing strings, and join(stn_list) was really all I required.
Repr and Eval I think I get. Eval certainly. That's a familiar concept, and one I hope to use tomorrow to feed a line to psycopg2. I might have opened a can of worms on map and repr though... I'll do some more reading tomorrow. Top tip on the code annotation, I didn't really think that through. Thanks again, Andy -- http://mail.python.org/mailman/listinfo/python-list
