yes and I explained it as basically as I can. his issue is wrongly trying to evaluate an element by doing if list[item] == 0
OK, I do get it. (I think.) Code works now. Thank you and thanks to APL for the time you guys spent explaining it.
Now I'm ready to move on. The original problem in the book of puzzles was an 8 X 8 grid. Each horizontal line similar to my PLst: [2, 0, 4, 5, 7, 0, 3, 2] with some of the numbers in each line missing. Those are the ones I filled in with zero.
The challenge is to make each horizontal line AND each vertical line add to thirty. Well, I'll just type the entire puzzle.
[2, 0, 4, 5, 7, 0, 3, 2]
[0, 4, 1, 6, 0, 1, 9, 0]
[4, 0, 0, 1, 0, 8, 2, 4]
[1, 5, 0, 0, 5, 0, 0, 2]
[0, 6, 4, 3, 0, 4, 2, 6]
[7, 3, 4, 0, 2, 5, 1, 0]
[0, 1, 6, 7, 1, 0, 0, 2]
[1, 0, 2, 0, 3, 2, 5, 0]
So all sixteen lines have to add to thirty. Now that you've pointed me in the right direction, I'm going to forge ahead and attempt to finish the puzzle.