python - Why does this not work as an array membership test?

Question

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Answer 1

This is a chained comparison. You may have known that you can do

1 < 2 < 3

in Python, and it's equivalent to (1 < 2) and (2 < 3). (Or maybe you didn't. Now you know.) Well, the same thing applies to in and ==.

5 in [1, 2, 3, 4] == False

is equivalent to

(5 in [1, 2, 3, 4]) and ([1, 2, 3, 4] == False)

Since [1, 2, 3, 4] is not equal to False, the whole expression evaluates to False.