An alternative to global in Python

Question

I currently have code like this:

cache = 1
def foo():
    global cache
    # many
    # lines
    # of code
    cache = 2

However, this may

Answer 1

"the reader may unintentionally think that the global variable has been updated" isn't much of a pitfall. You have to expect that people reading your code know how Python works. If you want to make it extra clear, use a comment. That's what they're for.

Answer 2

cache = 1
def foo():
    return 2
cache = foo()

or

d = {'cache': 1}
def foo(x):
    x['cache'] = 2
foo(d)

Answer 3

Using global variable is not a good programming practice. Pass the variable as an argument: make function returns something and use it in another function. Function can be assignment to variable that's how Python works.

Answer 4

class Cache:
     myvar = 1

def foo():
    Cache.myvar = 2

This way, Cache.myvar is practically a "global". It's possible to read/write to it from anywhere.

I prefer this over the dictionary alternative, because it allows for auto-complete of the variable names.