Question

consider this

# global variable
i_am_global = {}

def get_global():
    global i_am_global # declare 1
    if i_am_global is not None:
        return i_am_global
    global i_am_global # declare 2
    i_am_global = do_something()
    return i_am_global
def main():
    get_global()
if __name__ == "__main__":
    main()

in this scenario where do we need to put global ? at # declare 1 or at # declare 2? and why?

This is because I heard(so I am asking this question) that global causes memory overhead. Please correct my understanding

Thank you

Answer 1

If you only ever read the variable, then you don’t have to use global, but personally I do for documentary reasons. I also use a naming convention for globals. I don’t believe there is a memory overhead for the global keyword, but globals in themeselves are generally considered to be undesirable.