"x == None" vs "x is None"
Ulli Horlacher
framstag at rus.uni-stuttgart.de
Sun Jan 17 06:05:15 EST 2016
Chris Angelico <rosuav at gmail.com> wrote:
> On Sun, Jan 17, 2016 at 8:51 PM, Ulli Horlacher
> <framstag at rus.uni-stuttgart.de> wrote:
> > I have seen at several places "x == None" and "x is None" within
> > if-statements.
> > What is the difference?
> > Which term should I prefer and why?
>
> tl;dr: Prefer "x is None" as a check.
And for the negation?
"if not x is None" or "if x is not None"
I have seen the last one several times, but i do not understand it, because:
>>> x=0
>>> x is not None
True
>>> not None
True
>>> x is True
False
--
Ullrich Horlacher Server und Virtualisierung
Rechenzentrum IZUS/TIK E-Mail: horlacher at tik.uni-stuttgart.de
Universitaet Stuttgart Tel: ++49-711-68565868
Allmandring 30a Fax: ++49-711-682357
70550 Stuttgart (Germany) WWW: http://www.tik.uni-stuttgart.de/
More information about the Python-list
mailing list