[Python-ideas] Unpack of sequences

[M.-A. Lemburg]

Steven D'Aprano wrote:
> On 30/08/12 04:16, M.-A. Lemburg wrote:
> 
>>>>> d = dict(a=1, b=2, c=3)
>>>>> locals().update(d)
>>>>> a
>> 1
>>>>> b
>> 2
>>>>> c
>> 3
>>
>> Not that I'd recommend doing this, but it's possible :-)
> 
> 
> Try it inside a function.
> 
> 
> py> def test():
> ...     d = dict(a=1, b=2, c=3)
> ...     locals().update(d)
> ...     print a
> ...
> py> test()
> Traceback (most recent call last):
>   File "<stdin>", line 1, in <module>
>   File "<stdin>", line 4, in test
> NameError: global name 'a' is not defined

Yeah, that's because functions use fast locals, which locals()
only mirrors as dictionary.

You have to play some tricks to it work...

def f(d):
    from test import *
    locals().update(d)
    print a,b,c

d = dict(a=1, b=2, c=3)
f(d)

...and because you're not supposed to do this, you get a SyntaxWarning :-)

-- 
Marc-Andre Lemburg
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