为什么 10 和 5 在 python 中返回 5 和 5 和 10 返回 10？ 基本上它在和操作符之后返回第二个 int 值，而不考虑值

Question

I was looking into python "and" operator and found out:

>>> 10 and 5
5
>>> 5 and 10
10

Answer 1

Think of statement logic and which operand determines the value of the entire expression:

and :

• the first falsy operand makes the expression False regardless of what comes after
• if there are only truthy operands, the last one settles it

Examples:

>>> 5 and 0
0
>>> 0 and 5
0 
>>> 5 and 0 and 3
0 
>>> 10 and 5
5
>>> 5 and 10
10

or :

• the first truthy operand makes the expression True regardless of what comes after
• if there are only falsy operands, the last one settles it

Examples:

>>> 5 or 0
5
>>> 0 or 5
5 
>>> 5 or 0 or 3
5 
>>> 10 or 5
10
>>> 5 or 10
5

Shot-Circuit behaviour:

Note that the rest of the expression is not even evaluated, which is relevant if you chain egfunction calls or other expressions with side effects:

>>> 4/0 or 5
ZeroDivisionError
>>> 5 or 4/0
5
>>> func1() or func2() and func3()
# func2 and func3 might never be called

Right-Left-Associativity

This is kind of directly required for the short-circuit behaviour, but not completely intuitive, especially compared to Python's arithmetic operators:

a or b and c or d == (a or (b and (c or d)))