On Sat, Feb 20, 2010 at 5:53 PM, Steven D'Aprano <st...@remove-this-cybersource.com.au> wrote: > On Sat, 20 Feb 2010 17:34:15 -0800, Jonathan Gardner wrote: >> In terms of "global", you should only really use "global" when you are >> need to assign to a lexically scoped variable that is shared among other >> functions. For instance: >> >> def foo(): >> i = 0 >> def inc(): global i; i+=1 >> def dec(): global i; i-=1 >> def get(): return i >> return (inc, dec, get) > > That doesn't do what you think it does: > > >>>> def foo(): > ... i = 0 > ... def inc(): global i; i+=1 > ... def dec(): global i; i-=1 > ... def get(): return i > ... return (inc, dec, get) > ... >>>> inc = foo()[0] >>>> inc() > Traceback (most recent call last): > File "<stdin>", line 1, in <module> > File "<stdin>", line 3, in inc > NameError: global name 'i' is not defined > > > The problem is that i is not global. Inside the inc and dec functions, > you need to declare i nonlocal, not global, and that only works in Python > 3 or better. >
Oops. :-( -- Jonathan Gardner jgard...@jonathangardner.net -- http://mail.python.org/mailman/listinfo/python-list
