if语句中多个条件的Python速记

Question

if x == y != z:
    print (x + y)

如果x==y和y！=z？它在我的代码中工作，但我不确定当多个条件不是全部==或时如何解释它们！=，或以上述后一种形式写出。你知道吗

Answer 1

是的，如documentation中所述：

(...)

Comparisons can be chained arbitrarily, e.g., x < y <= z is equivalent to x < y and y <= z, except that y is evaluated only once (but in both cases z is not evaluated at all when x < y is found to be false).

因此您可以链接任何类型的比较器：<、>、==、>=、<=、<>、!=、is [not]和[not] in。你知道吗

文件进一步使其更加正式：

Formally, if a, b, c, ..., y, z are expressions and op1, op2, ..., opN are comparison operators, then a op1 b op2 c ... y opN z is equivalent to a op1 b and b op2 c and ... y opN z, except that each expression is evaluated at most once.

例如：

'a' in 'ab' in 'zabc'

相当于：

'a' in 'ab' and 'ab' in 'zabc'