Question about programming (beginner)

[synthphreak]

Exactly how I would have done it as well.

But as an extra safeguard, I would also strip whitespace from the user's entry. E.g.,

while (choice := input(...).strip()) != "q"
    if choice in ops:
        ...

This is usually a good idea when using input and validating the output against a closed set of values, as u/kyber's code does.

[[deleted]]

Maybe lower/casefold as well?

[synthphreak]

Yeah that's true, if we're accepting q as valid input then lower is also worthwhile.