Python 3 - Second Edition

17.11    Namespaces

Up to this point, a function body has been considered as an encapsulated section that can exchange information with the main program only via parameters or the return value. At first, this isn’t a bad way of looking at things because it keeps your interface "clean." In some situations, however, it makes sense to let a function act beyond its local namespace, as we’ll discuss in this section.

17.11.1    Accessing Global Variables: global

First, we must distinguish between two concepts: If you are in the context of a function—that is, in the function body—then you can of course create and use references and instances there. However, these are only accessible inside the function body during a function call. They exist in the ...