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

The second example implements what is called a closure. The function bar is referencing the variable x from its surrounding context, i.e. the function foo. This precedes the reference to the global variable x.

See also this question Can you explain closures (as they relate to Python)?