python3 -- nested while loop driven user input menu decision tree - python-3.x

Question

I have been stumped on this one for too long and I need some help. I am trying to create a user input menu decision tree that will lead the user to the appropriate function call. I just cant seem to get the path to function correctly. I keep getting stuck in the second loop. I have tried many different logics and conditions but nothing has made it work. I created some simple code that I think clearly shows what I am trying to achieve...
def menu():
print("1. Selection 1")
print("2. Selection 2")
print("3. Quit")
def menu1():
print("1.Selection Function 1")
print("2.Selection Function 2")
print("3.Quit")
def menu2():
print("1.Selection Function 3")
print("2.Selection Funtion 4")
print("3.Quit")
def func_1():
print("Funtion_1")
def func_2():
print("Funtion_2")
def func_3():
print("Funtion_3")
def func_4():
print("Funtion_4")
if __name__ == '__main__':
menu()
selection=int
selection1=int
selection2=int
while (selection != 3):
selection==int(input("Please Select a Menu Option: "))
if selection == 1:
menu1()
while ((selection1 != 3)):
selection1==int(input("What Type of funtion Would You Like To execute: "))
if selection1 == 1:
func_1()
if selection1 == 2:
func_2()
if selection1 == 3:
sys.exit()
elif selection == 2:
menu2()
while ((selection2==int(input("What Other Type of Function Would You Like To execute: ")) != 3)):
if selection2 == 1:
func_3()
if selection2 == 2:
func_4()
if selection2 == 3:
sys.exit()
elif selection == 6:
sys.exit()

Answer 1

Looks like you need to break out of the while loop instead of doing sys.exit() in the inner loops. If you do sys.exit() on inner loops it will exit and won't come back to the outer menu option.
your this line selection==int(input("Please Select a Menu Option: ")) should be selection=int(input("Please Select a Menu Option: ")). == is used for comparison not for assignment. for assignment we use =
Here, is modified code which works as expected.
def menu():
print("1. Selection 1")
print("2. Selection 2")
print("3. Quit")
def menu1():
print("1.Selection Function 1")
print("2.Selection Function 2")
print("3.Quit")
def menu2():
print("1.Selection Function 3")
print("2.Selection Funtion 4")
print("3.Quit")
def func_1():
print("Funtion_1")
def func_2():
print("Funtion_2")
def func_3():
print("Funtion_3")
def func_4():
print("Funtion_4")
if __name__ == '__main__':
menu()
selection=int
selection1=int
selection2=int
while (selection != 3):
selection=int(input("Please Select a Menu Option: "))
if selection == 1:
menu1()
while ((selection1 != 3)):
selection1=int(input("What Type of funtion Would You Like To execute: "))
if selection1 == 1:
func_1()
if selection1 == 2:
func_2()
if selection1 == 3:
break
elif selection == 2:
menu2()
while (selection2 != 3):
selection2=int(input("What Other Type of Function Would You Like To execute: "))
if selection2 == 1:
func_3()
if selection2 == 2:
func_4()
if selection2 == 3:
break
elif selection == 6:
sys.exit()

Answer 2

You are comparing selection with integer. Where selection has datatype, it will false forever. Instead do this selection == type(3) and this won't solve your problem.
One more thing is, first line in while loop
selection==int(input("Please Select a Menu Option: "))
here you are comparing(==), not assigning value(=).
selection=int(input("Please Select a Menu Option: "))
use single equals to symbol.
You can't compare the numbers, so you won't get required results, loops will be same for all numbers. For that you need to store numbers in selection variable.
Ask for further queries.