On Friday, December 11, 2015 at 9:53:10 AM UTC-8, Robin Koch wrote:
> Am 11.12.2015 um 17:39 schrieb Ian Kelly:
> > On Fri, Dec 11, 2015 at 9:24 AM, Robin Koch <robin.k...@t-online.de> wrote:
> >> Assigning goes from right to left:
> >>
> >> x,y=y,x=2,3
> >>
> >> <=>
> >>
> >> y, x = 2, 3
> >> x, y = y, x
> >>
> >> Otherwise the assignment x, y = y, x would not make any sense, since x and
> >> y
> >> haven't any values yet.
> >>
> >> And the execution from right to left is also a good choice, because one
> >> would like to do something like:
> >>
> >> x = y = z = 0
> >>
> >> Again, assigning from left to right woud lead to errors.
> >
> > No, it actually happens left to right. "x = y = z = 0" means "assign 0
> > to x, then assign 0 to y, then assign 0 to z." It doesn't mean "assign
> > 0 to z, then assign z to y, etc."
>
> Oh. Ok, then, thanks for this correction.
> Although it's consequent to use left-to-right precedence it's a little
> counter intuitive in the sense that the rightmost and leftmost objects
> interact. Especially with a background in mathematics. :-)
>
> > This works:
> >
> >>>> d = d['foo'] = {}
> >>>> d
> > {'foo': {...}}
> >
> > This doesn't:
> >
> >>>> del d
> >>>> d['foo'] = d = {}
> > Traceback (most recent call last):
> > File "<stdin>", line 1, in <module>
> > NameError: name 'd' is not defined
>
> Good to know! Thank you.
>
> --
> Robin Koch
Yeh, Your discussion is very good, really I understood correct process, Thank
you very much all of you!
--
https://mail.python.org/mailman/listinfo/python-list
