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How does the in operator work in Python?

Q: How does the in operator work in Python?

`x in obj` (membership testing) dispatches in a defined order, so its cost depends entirely on the container: x in obj 1. __contains__(x) set/dict: O(1) hash lookup 2. __iter__ and compare each list/t

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contains and fallbacks.

incontains

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PYCustom __contains__ and the generator-drain gotcha

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