How to avoid inconsistent s[i:-j] slicing behaviour when j is sometimes 0?

Question

I am creating a number of slices [-WINDOW-i:-i] of a list, where i ranges between 32 and 0:

vals = []

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Answer 1

One workaround for this quirk in Python slicing is to take advantage of these facts:

1. false_ish_value or other_value always evaluates to other_value
2. 0 is the only integer that is false-ish in a boolean context
3. s[n:None] is equivalent to s[n:]

With those in mind, you can write your slice as:

other_list[-WINDOW-i:(-i or None)]

… and the slice will be interpreted as [-WINDOW-i:None] (which is the same as [-WINDOW-i:]) only when i (and therefore -i) is 0.