checking if a list is empty

[rusi]

On May 15, 4:26 am, Ben Finney <ben+pyt... at benfinney.id.au> wrote:
> rusi <rustompm... at gmail.com> writes:
> > [Steven quote]
> > In Python, [1, 2, 3] is another way of writing true, and [] is another
> > way of writing false. Similarly with any other arbitrary objects. The
> > only things that bools True and False are good for are:
> > <snipped>
> > [end Steven quote]
> > ------------------------
>
> > So since
> > [1,2,3] is one way of writing True (lets call it True3)
>
> No. Steven knew exactly why he was using “true” versus “True”. He's
> explained why elsewhere in this thread. The former does not refer to the
> Python boolean singleton, the latter does.
>
> The only object that is True is the True singleton. But there are many
> objects that are true.

Yes.
The python entities: {True, False} are not an exact (isomorphic) model
for the semantic boolean domain {true, false} (which is needed for
example to explicate the semantics of if while etc)  Which is to say
the boolean type in python is not first class.