global in python

1"""
2USING GLOBALS ARE A BAD IDEA, THE BEST WAY TO PERFORM AN ACTION WHICH NEEDS GLOBALS WOULD 
3BE TO USE RETURN STATEMENTS. GLOBALS SHOULD ONLY EVER BE USED IN RARE OCCASIONS WHEN YOU
4NEED THEM
5"""
6
7# allows you to modify a variable outside its class or function
8
9EXAMPLE:
10  
11def test_function():
12  global x
13  x = 10
14
15test_function()
16print(f"x is equal to {x}") # returns x is equal to 10
17

1globvar = 0
2
3def set_globvar_to_one():
4    global globvar    # Needed to modify global copy of globvar
5    globvar = 1
6
7def print_globvar():
8    print(globvar)     # No need for global declaration to read value of globvar
9
10set_globvar_to_one()
11print_globvar()       # Prints 1

1a = 'this is a global variable'
2def yourFunction(arg):
3    #you need to declare a global variable, otherwise an error
4    global a
5    return a.split(' ')
6    

1#### A_FILE.PY
2a_global_variable = "Hello"
3####sys.path.append(".")
4
5##### B_FILE.PY
6import a_file
7
8output = a_file.a_global_variable
9
10print(output)
11------> Hello

1c = 0 # global variable
2
3def add():
4    global c
5    c = c + 2 # increment by 2
6    print("Inside add():", c)
7
8add()
9print("In main:", c)

1
2x = 5 #Any variable outside a function is already a global variable
3
4def GLOBAL():
5	global y #if a variable is inside a function, use the 'global' keyword to make it a global variable
6    y = 10 # now this variable (y) is global