How to call variable from another function by declaring global in python?

Question

func 1

def num1():
    global h
    h=7

func 2

def num2():  
     print(h)

When I call this function:

num2()

Here, it should print the value of h which is globally declared in func 1. But it is giving NameError why?? Anyone answer me plz..

and another thing: using global variables to share variables between functions is a bad habbit (unless you use them as constant variables such as MAX_VALUE = 100 where you want the max to be the same everywhere. but in this case you don't change its value). a better practice is either pass the variable as a parameter to the functions that use it , or put them both under a class and change this global variable to a class attribute — Gal
– Gal, Commented May 24, 2020 at 18:03

lorem_bacon · Accepted Answer · 2020-05-24 18:03:22Z

1

to access the global variable h through num2() make sure to call num1() before calling num2()

answered May 24, 2020 at 18:03

lorem_bacon

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Comments

chepner · Accepted Answer · 2020-05-24 18:09:46Z

0

Defining num1 doesn't actually define h. The definition of num1 just says that, when you call num1, it will assign to the global name h. If h doesn't exist at that time, it will be created. But defining num1 isn't sufficient to create h.

You need to ensure that h exists before num2 is called. You can do that by assigning to h yourself, or calling num1.

>>> num2()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 2, in num2
NameError: name 'h' is not defined
>>> h = 3
>>> num2()
3
>>> del h
>>> num2()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 2, in num2
NameError: name 'h' is not defined
>>> num1()
>>> num2()
7

answered May 24, 2020 at 18:09

chepner

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