间隔比较如何工作？ [英] How does interval comparison work?

问题描述

以某种方式起作用，

def in_range(min, test, max):
    return min <= test <= max

print in_range(0, 5, 10)  # True
print in_range(0, 15, 10)  # False

但是，我不太清楚这里的操作顺序。让我们测试 False 的情况：

However, I can't quite figure out the order of operations here. Let's test the False case:

print 0 <= 15 <= 10  # False
print (0 <= 15) <= 10  # True
print 0 <= (15 <= 10)  # True

很显然，这并不能解决简单的操作顺序问题。区间比较是一个特殊的运算符，还是其他的事情？

Clearly, this isn't resolving to a simple order of operations issue. Is the interval comparison a special operator, or is something else going on?

推荐答案

与大多数语言不同，Python支持链式比较运算符，并且可以像在普通数学中对它们进行评估那样对其进行评估。

Unlike most languages, Python supports chained comparison operators and it evaluates them as they would be evaluated in normal mathematics.

此行：

return min <= test <= max

由Python评估如下：

is evaluated by Python like this:

return (min <= test) and (test <= max)

大多数其他语言都会这样评价它：

Most other languages however would evaluate it like this:

return (min <= test) <= max

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