while true: !!!

Alex Martelli aleaxit at yahoo.com
Tue Dec 19 11:10:30 CET 2000


"Rainer Deyke" <root at rainerdeyke.com> wrote in message
news:KTz%5.48644$x6.22165257 at news2.rdc2.tx.home.com...
> "Steve Lamb" <grey at despair.rpglink.com> wrote in message
> news:slrn93t7bv.le.grey at teleute.rpglink.com...
> > On Mon, 18 Dec 2000 23:32:23 +0100 (MET), Carsten Geckeler
> <nospam at no.spam>
> > wrote:
> > >`while true' would be more readable and clear than `while 1'.  By the
> way,
> > >explain a newbie that -1 is true. ;)
> >
> >     0 is true, all else is false.  And?  :P
>
> 0 is false, None is false, [] is false, () is false, {} is false, and x is
> false where x is a class instance and x.__nonzero__() returns false.
> Everything else is true.  I think.

Another couple of 'false's: a class instance which doesn't define
__nonzero__ but does define __length__ when the latter returns 0;
and, C-implemented user objects, similarly to class instances.

I don't _think_ there are any more...


Alex






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