[Tutor] Global var problem

[Nick Lunt]

Hi Folks,

messing about with classes I've come across something basic that I don't 
understand.

Take this class

class T:
        def p(self):
                print x

if __name__ == '__main__':
        x = 1
        t = T()
        t.p()

This outputs 1

Now this
class T:
        def p(self):
                x += 1
                print x

if __name__ == '__main__':
        x = 1
        t = T()
        t.p()

This outputs
UnboundLocalError: local variable 'x' referenced before assignment

So I tried this

class T:
        def p(self):
                x += 1
                print x

if __name__ == '__main__':
        global x
        x = 1
        t = T()
        t.p()

but that gives me the same UnboundLocalError exception.

This has got me confused. Why does the first example work ok, but not 
the second ?
And in the third example I get the same error even after declaring x to 
be global.

No doubt the answer is staring me in the face ... but I still can't see it.

Cheers
Nick .