How to access variables in more global functions within a nested function? (Python)

Question

I am running a function within another function. However, the more nested function is unable to access the variables in the main, more global function. When I attempt to run my code I get "x is not defined" error. I would think that since x is a more global variable higher in scope, it should be accessible.

def func_master():
    x = 'hello world'
    test_sub()


def test_sub():
    print(x)

func_master()

I want it to print out 'hello world'.

Python had lexical, not dynamic, variable scope, so what you want must be achieved by other means such as explicit passing of arguments, or using globals. — user4815162342
– user4815162342, Commented Jul 11, 2019 at 15:48

Rory Daulton · Accepted Answer · 2019-07-11 15:45:53Z

3

Your functions are not "nested," which means that one is defined inside the other. You instead are calling one function from inside another, but the functions are defined separately, neither inside the other.

Python's scope rules are based on how the functions are defined. So when func_master calls test_sub, the name x that was defined in func_master is not accessible to test_sub.

The best (but not only) way to make x usable in test_sub is to pass it as a parameter. Modify the call in func_master to pass x and modify the definition of test_sub to receive it. It is good programming practice for one routine to pass all the needed information as parameters--avoid using global variables etc. unless they are absolutely needed.

def func_master():
    x = 'hello world'
    test_sub(x)


def test_sub(x):
    print(x)

func_master()

answered Jul 11, 2019 at 15:45

Rory Daulton

22.7k7 gold badges46 silver badges51 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

visualbread Over a year ago

Thanks! I am glad there is a way to do this without using global variables. I was imagining a case with multiple functions within functions within functions, and using only globals seemed like a headache. Also, thanks for helping me with my terminology. I am very new, and still trying to get the words right.

Collectives™ on Stack Overflow

How to access variables in more global functions within a nested function? (Python)

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related