Unbound Local Error with global variable

Question

I am trying to figure out why I get an UnboundLocalError in my pygame application, Table Wars. Here is a summary of what happens:

The variables, REDGOLD

Answer 1

Found that variables in main act like global "read only" variables in function. If we try to reassign the value, it will generate error.

Try:

#!/usr/bin/env python
RED=1
A=[1,2,3,4,5,6]

def f():
    print A[RED]

f()

It's ok.

But:

#!/usr/bin/env python
RED=1
A=[1,2,3,4,5,6]

def f():
    print A[RED]
    A = [1,1,1,1,1]

f()

Generate

  File "./test.py", line 6, in f
    print A[RED]
UnboundLocalError: local variable **'A'** referenced before assignment

and:

#!/usr/bin/env python
RED=1
A=[1,2,3,4,5,6]

def f():
    print A[RED]
    RED = 2

f()

Generate

  File "./test.py", line 6, in f
    print A[RED]
UnboundLocalError: local variable **'RED'** referenced before assignment