python: how binding works

Question

I am trying to understand, how exactly variable binding in python works. Let\'s look at this:

def foo(x):
    def bar():
        print y
    return bar

y =          


        

Answer 1

Nothing strange, it is because "x" from function argument has higher priority than global variable "x".

At first, global variables is a great evil.

Python has operator "global":

>>> def foo(x):
...     def bar():
...          global x
...          print x
...     return bar
... 
>>> x = 5
>>> bar = foo(2)
>>> bar()
5