namespace hacking question

[bruno.desthuilliers at gmail.com]

On 1 oct, 14:12, Fuzzyman <fuzzy... at gmail.com> wrote:
> On Sep 30, 6:07 pm, kj <no.em... at please.post> wrote:
>
>
>
> > This is a recurrent situation: I want to initialize a whole bunch
> > of local variables in a uniform way, but after initialization, I
> > need to do different things with the various variables.
>
> > What I end up doing is using a dict:
>
> > d = dict()
> > for v in ('spam', 'ham', 'eggs'):
> >     d[v] = init(v)
>
> > foo(d['spam'])
> > bar(d['ham'])
> > baz(d['eggs'])
>
> > This is fine, but I'd like to get rid of the tedium of typing all
> > those extra d['...']s.
>
> > I.e., what I would *like* to do is something closer to this:
>
> > d = locals()
> > for v in ('spam', 'ham', 'eggs'):
> >     d[v] = init(v)
>
> > foo(spam)
> > bar(ham)
> > baz(eggs)
>
> > ...but this results in errors like "NameError: global name 'spam' is
> > not defined".
>
> > But the problem is deeper than the fact that the error above would
> > suggest, because even this fails:
>
> > spam = ham = eggs = None
> > d = locals()
> > for v in ('spam', 'ham', 'eggs'):
> >     d[v] = init(v)
>
> > foo(spam) # calls foo(None)
> > bar(ham)  # calls bar(None)
> > baz(eggs) # calls baz(None)
>
> > In other words, setting the value of locals()['x'] does not set
> > the value of the local variable x.
>
> > I also tried a hack using eval:
>
> > for v in ('spam', 'ham', 'eggs'):
> >     eval "%s = init('%s')" % (v, v)
>
> > but the "=" sign in the eval string resulted in a "SyntaxError:
> > invalid syntax".
>
> > Is there any way to use a loop to set a whole bunch of local
> > variables (and later refer to these variables by their individual
> > names)?
>
> One way:
>
> import sys
> module = sys.modules[__name__]
>
> for entry in ('spam', 'eggs', 'ham'):
>     setattr(module, entry, 'some value')
>

Only works on globals - which you can already set using globals()
IIRC.