Boolean Expressions

[Chris Angelico]

On Wed, Sep 27, 2017 at 7:43 AM, Cai Gengyang <gengyangcai at gmail.com> wrote:
> Help check if my logic is correct in all 5 expressions
>
>
> A) Set bool_one equal to the result of
> False and False
>
> Entire Expression : False and False gives True because both are False

This is not correct, and comes from a confusion in the English
language. In boolean logic, "and" means "both". For instance:

*IF* we have eggs, *AND* we have bacon, *THEN* bake a pie.

Can you bake an egg-and-bacon pie? You need *both* ingredients. The
assertion "we have eggs" is True if we do and False if we do not; and
the overall condition cannot be True unless *both* assertions are
True.

In Python, the second half won't even be looked at if the first half
is false. That is to say, Python looks beside the stove to see if
there's a carton of eggs, and if it can't see one, it won't bother
looking in the freezer for bacon - it already knows we can't bake that
pie.

Your other questions are derived from this one, so you should be fine
once you grok this one concept.

ChrisA