Hi,
6, -1 or 0 are not bools (True or False):
>>> 6 is True
False
>>> 0 is False
False
If you had to design a language and want to think about using numbers
in a logical context you could do at least two things:
1) convert the number to bool, ie define a set of rules to assign to
each number a logical value, or
2) don't convert and raise an error.
In python, like in many other languages, option 1) has been chosen.
The rules are roughly: when using a number in a logical context 0 is
casted to False, and the other numbers are considered True.
The "while" statement expects an expression that returns a logical
value. Put both things together and I think you get your answer, if I
well understood.
Best
2014-05-20 10:25 GMT+02:00 Ian D <dux...@hotmail.com>:
> I was reading a tutorial that had these examples in it:
>
>
>>>> while False:
>
> print("False is the new True.")
>
>
>>>> while 6:
>
> print("Which numbers are True?")
>
>
> while -1:
>
> print("Which numbers are True?")
>
>
> while 0:
>
> print("Which numbers are True?")
>
>
>
> Unfortunately the author never explained these statements.
>
>
> I was wondering if the gist of a while statement could be explained in the
> context of these examples.
>
>
> e.g. while False:
>
>
> means while True is False, which is never True because True is of course True
> not False.
>
>
> but while 6:
>
>
> means..... err while 6 is True? and this is True because... err.
>
>
> Anyway I am a bit lost with this.
>
>
> Can anyone shed any light please?
>
>
> Thanks.
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