How do you set a variable from an input in a module - module

Question

So, I'm trying to set a variable in my main program to an integer input from a function in a module. I can't work out how to do this.
This is my main program. Menu is the name of my module, as I'm using it to display a menu. 'menulist' is where you say what you want the menu to display. That part works OK.
import time, sys
from menu import *
menulist = ['Say hi', 'Say bye', 'Say yes', 'Say no', 'Exit']
choice = int(0)
menu(menulist)
choosing(menulist, choice)
print(choice) ##This is so I can see what it is
if choice == 1:
print('Say hi')
elif choice == 2:
print('Say bye')
elif choice == 3:
print('Say yes')
elif choice == 4:
print('Say no')
elif choice == 5:
sys.exit()
else: ##This will print if choice doesn't equal what I want
print('Error')
This is my module.
import time
def menu(menulist):
print('Menu:')
time.sleep(1)
x = 0
while x < len(menulist):
y = x + 1
printout = ' ' + str(y) + '. ' + menulist[x]
print(printout)
x = x + 1
time.sleep(0.3)
time.sleep(0.7)
print('')
def choosing(menulist, choice):
flag = True
while flag:
try:
choice = int(input('Enter the number of your choice: '))
time.sleep(0.8)
if choice < 1 or choice > len(menulist):
print('That wasn\'t an option sorry')
time.sleep(1)
else:
flag = False
except ValueError:
print('That wasn\'t an option sorry')
time.sleep(1)
The menu function works fine, and the choosing function almost does what I want it to, but it won't set 'choice' in my main program to the input when I call it from my module. Sorry if it's something blatantly obvious, I'm pretty new to programming. Thanks

Answer 1

Your module doesn't recognise choice as a global variable. Inside def choosing(...), choice is simply a local variable that gets assigned the value of your input (converted to an int).
You do pass choice to choosing, but since you've set choice to 0 before that, it is an immutable variable, and Python has (behind the scenes) created a local copy. So for all matters, choice is a local variable inside choosing.
Once your program leaves the function choosing, the variable and its value simply disappear (for all practical purposes).
To solve this, you shouldn't attempt to make choice global: generally, that is bad design (plenty of exceptions, but still, don't).
Instead, you can simply return choice from the function, and assign it in your main program. Relevant part of your module:
def choosing(menulist):
while True:
try:
choice = int(input('Enter the number of your choice: '))
time.sleep(0.8)
if choice < 1 or choice > len(menulist):
print('That wasn\'t an option sorry')
time.sleep(1)
else:
break
except ValueError:
print('That wasn\'t an option sorry')
time.sleep(1)
return choice
(I made a slight alteration here: you can simply use the break statement to break out of the continous while loop, instead of the extra flag variable.)
Note: there is no need to assign an initial value to choice: the function is structured to it always has to pass through the line choice = int(.... That, or it exist with an exception other than ValueError.
The relevant part of your main program:
import time, sys
from menu import *
menulist = ['Say hi', 'Say bye', 'Say yes', 'Say no', 'Exit']
menu(menulist)
choice = choosing(menulist)
Together with my above note: no need for an initial value of choice.
Finally: see how choice has disappeared from the parameters in the function, both in the call to and the definition of choosing.
That last point suggest to me that you might be coming from a different programming language. In Python, it is rare to pass a parameter to a function to have it altered. You simply return it, because that is easy and clearer. In you have multiple variables to alter, you can for example return a tuple: return a, b, c. Or a dict, or whatever you fancy (but the tuple is the starting point for multiple return values).