accessing module global vars by name

[Martin Drautzburg]

Withing a module I can assign a value to a global var by assigning to
it in the outermost scope. Fine.

But how can I do this if the attribute name itself is kept in a
variable. Once the module is loaded I can access the module's
namespace no problem, but inside the module the dictionary is not yet
present right ?

IOW how can I write something like

# xxx.py

for varName in ("foo", "bar"):
magic.varName = 1

so I can later refer to them as

# yyy.py
import xxx
x = xxx.foo
y = xxx.bar

[Steven Bethard]

Re: accessing module global vars by name

Martin Drautzburg wrote:[color=blue]
> IOW how can I write something like
>
> # xxx.py
>
> for varName in ("foo", "bar"):
> magic.varName = 1
>[/color]

I think you want to use the dict returned by globals(). Modifying this
dict can add/remove names from the global scope.[1]
[color=blue][color=green][color=darkred]
>>> foo[/color][/color][/color]
Traceback (most recent call last):
File "<interacti ve input>", line 1, in ?
NameError: name 'foo' is not defined[color=blue][color=green][color=darkred]
>>> bar[/color][/color][/color]
Traceback (most recent call last):
File "<interacti ve input>", line 1, in ?
NameError: name 'bar' is not defined[color=blue][color=green][color=darkred]
>>> for var_name in ['foo', 'bar']:[/color][/color][/color]
.... globals()[var_name] = True
....[color=blue][color=green][color=darkred]
>>> foo[/color][/color][/color]
True[color=blue][color=green][color=darkred]
>>> bar[/color][/color][/color]
True[color=blue][color=green][color=darkred]
>>> del globals()['foo']
>>> foo[/color][/color][/color]
Traceback (most recent call last):
File "<interacti ve input>", line 1, in ?
NameError: name 'foo' is not defined

Steve

[1] As an aside, be careful not to try the same thing with locals().
locals() returns a dict that won't modify names in the local scope.

[Peter Hansen]

Re: accessing module global vars by name

Martin Drautzburg wrote:[color=blue]
> Withing a module I can assign a value to a global var by assigning to
> it in the outermost scope. Fine.
>
> But how can I do this if the attribute name itself is kept in a
> variable. Once the module is loaded I can access the module's
> namespace no problem, but inside the module the dictionary is not yet
> present right ?[/color]

Look into the builtin function globals()...

-Peter