Why does `(1 in [1,0] == True)` evaluate to `False` in Python?

False Evaluation of (1 in [1,0] == True)

Unlike a typical programming language, Python evaluates expressions using comparison operator chaining. In the expression (1 in [1,0] == True), the operation is not parsed as expected.

The expression is actually interpreted as:

(1 in [1, 0]) and ([1, 0] == True)

This evaluation breaks down into:

• (1 in [1, 0]): This evaluates to True because 1 is present in the list [1, 0].
• ([1, 0] == True): This evaluates to False because [1, 0] is a list, not a boolean value.

The overall expression, therefore, evaluates to:

True and False = False

This unexpected result highlights the difference in Python's evaluation of expressions compared to other languages. To avoid confusion, use parentheses to specify the desired evaluation order:

(1 in [1,0]) == True # True

The above is the detailed content of Why does `(1 in [1,0] == True)` evaluate to `False` in Python?. For more information, please follow other related articles on the PHP Chinese website!