[docs] Another strange expression, 2

[Al Sweigart]

This is an unfortunate side effect of chaining the == and in operators.
Look at this equivalent expression:

>>> spam = False
>>>  True == spam in (True, False)
False

The expression `True == spam in (True, False)` is equivalent to `(True ==
spam) and (spam in (True, False))`, which is why it evaluates to False.

This is similar to how `10 < spam < 20` is equivalent to `(10 < spam) and
(spam < 20)`, and not `(10 < spam) < 20` or `10 < (spam < 20)`

The lesson is to not mix different kinds of operators when chaining them.

-Al

On Tue, Jul 10, 2018 at 2:24 AM, Vrancken, J.L.M. (Jos) <
j.l.m.vrancken at hr.nl> wrote:

> True == False in (True, False)
>
>
>
> This expression gives False,
>
> whereas in any interpretation, it should be True:
>
>
>
> (True == False)  in (True, False)        returns True
>
>
>
> True == (False in (True, False))        returns True
>
>
>
> All this in Python 3.7.
>
>
>
> Is something wrong or am I'm wrong in thinking something's wrong here?
>
>
>
> Jos Vrancken
>
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