Python vars() global name error

Question

I\'m having a bit of trouble understanding what\'s going wrong with the following function:

def ness():
 pie=\'yum\'
 vars()[pie]=4
 print vars()[pie]
 print yum         


        

Answer 1

It's not safe to modify the dict returned by vars()

vars([object])¶

Without an argument, act like locals().

With a module, class or class instance object as argument (or anything else that has a dict attribute), return that attribute.

Note

The returned dictionary should not be modified: the effects on the corresponding symbol table are undefined.

Your second example is a special case. vars() is equivalent to globals() in the global namespace, and the dict returned by globals() behaves as you would expect ( but is frowned upon )

>>> id(vars()),id(globals())
(3085426868L, 3085426868L)