[alentred]

My rule of thumb: only using single letter variables in one-liners (and never if it spills to another line), or for something that is conventionally represented as such. So for example:

    ```python
    bar = [foo(e) for e in elements]
    ```

or, using `x`, `n`, `s` and similar when they represent just that, a generic variable with a number, string, etc. I think there is a Code Complete chapter about it.

[jazzypants]

Yeah, I'm not GP, but my exceptions to this rule are `i` for "iterator" in `for` loops and `e` for "event" in event listeners.

[NetMageSCW]

Don’t use ‘i’ (looks like 1), use ‘j1’, etc - helps set you up if you need a nested loop someday. Of course, at that point better naming would probably be best.