Quote from rosy2:
looks complicated compared to my approach which took about 3 minutes.
Exactly right. Excel is a spreadsheet. It's intended for accountants who need to add columns of numbers. Many push Excel beyond its comfort zone and winding up with an undebuggable, unverifiable mess, then have to backtrack and start over in another programming environment. Re your pandas/py solution, the same thing is doable in a few lines of R also.

