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pythoncomparisonparentheses

How a single parenthesis could change the output?

print(3 in [1, 2, 3] == [1, 2, 3])
#Output: True 

print((3 in [1, 2, 3]) == [1, 2, 3])
#Output: False

I'm just wondering what is happening here.

Solution

  • Because of Python's comparison chaining feature.

    3 in [1, 2, 3] == [1, 2, 3]

    is treated as

    (3 in [1, 2, 3]) and ([1, 2, 3] == [1, 2, 3])