namespace hacking question

kj at
Thu Sep 30 19:07:12 CEST 2010

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)


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)


...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



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