Question about scope

[Carsten Gaebler]

Tim Daneliuk wrote:

> I guess what I want to know is when globally declared objects are seen inside a function, class, or
> block, and when they must be explicitly declared as being global.

You can always 'read' a global variable in a function, e.g.

g = 0
def func():
  print g
func()

prints '0'. If you want to modify a global variable inside a function you
need to declare it as global:

g = 0
def func():
  global g
  g = 1
func()
print g

prints '1'.

Otherwise an assignment inside a function will create a new variable in
the local namespace:

g = 0
def func():
  g = 1
print g

prints '0' because g=1 only exists inside func().


Hope it helps.

cg.