I, as a rule, only use single-letter vars when iterating over an emumerable, in which it is clear what the single-letter var represents. Outside of that, never.

I, as a rule, only use single-letter vars when iterating over an emumerable, in which it is clear what the single-letter var represents. Outside of that, never. The single-letter var also is usually the first letter of whatever actual items are being iterated over. Something like: for c in customers: do_something(c)