Why this throws an UnboundLocalError ?
Ned Batchelder
ned at nedbatchelder.com
Thu Jan 30 17:56:17 EST 2014
On 1/30/14 5:46 PM, Marc Aymerich wrote:
> Dear all,
>
> I have a very simple module
>
> glic3 at e4200:# cat globalstate.py
> GLOBAL = 0
>
> def update():
> GLOBAL += 1
>
>
> however it doesn't work!!
>
> glic3 at e4200:# python
> Python 2.7.3 (default, Aug 1 2012, 05:14:39)
> [GCC 4.6.3] on linux2
> Type "help", "copyright", "credits" or "license" for more information.
>>>> import globalstate
>>>> globalstate.update()
> Traceback (most recent call last):
> File "<stdin>", line 1, in <module>
> File "globalstate.py", line 4, in update
> GLOBAL += 1
> UnboundLocalError: local variable 'GLOBAL' referenced before assignment
>
>
> And I don't know why :(
> Anyone ?
>
> Thanks!!
>
Assignment statements in functions implicitly make local names. If you
want to assign a new value to a global name in a function, you have to
use a global statement:
def update():
global GLOBAL
GLOBAL += 1
--
Ned Batchelder, http://nedbatchelder.com
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