Python 3 Jump Tables - python-3.x

Question

I am trying to figure out how to create a basic jump table, so I can better understand different ways of creating menus in Python 3.5.6. Here is what I have so far:
def command():
selection = input("Please enter your selection: ")
return selection
def one():
print ("you have selected menu option one")
def two():
print ("you have selected menu option two")
def three():
print ("you have selected menu option three")
def runCommand(command):
jumpTable = 0
jumpTable[command]()
jumpTable = {}
jumpTable['1'] = one
jumpTable['2'] = two
jumpTable['3'] = three
def main():
command()
runCommand(command)
if __name__ == "__main__":
main()
As far as I understand, a jump table is simply a way of making a menu selection and calling a specific function associated with that numerical value, taken in by my "command" function. Within the jumpTable, you assign the function to call.
I am getting " File "omitted", line 16, in runCommandjumpTableone
TypeError: 'int' object is not subscriptable
All I want to do is have the user enter a number - 1, 2 or 3 and have that function run. when I get this basic functionality down, I will expand the menu to show the options and be more clear. I just need to get the darn thing to run!
Yes, I am aware of other ways to create menus (IF/ELIF/ELSE) I am just trying to nail this one down!
Thank you in advance!

Answer 1

You are quite close. The only issue is that you are trying to access the command before creating the jumpTable. And I am also not sure why you are setting the variable to 0 first (that's why you get the int is not subscriptible error). So, this is the right order:
def runCommand(command):
jumpTable = {}
jumpTable['1'] = one
jumpTable['2'] = two
jumpTable['3'] = three
jumpTable[command]()
By the way, if you are always creating the same jumpTable, you could create it once, outside the function and simply call jumpTable[command]() in your main function.
Another problem: you should store the value you get from the user and pass that to the next function like this:
cmd = command()
runCommand(cmd)
, or simply pipe the two functions together like this:
runCommand(command())

Answer 2

"""
Based on the original question, the following will.
Add a menu to a console application to manage activities.
Run a selected function.
Clear the output
Display the menu again or exit if done is selected
"""
import sys
from os import system
def display_menu(menu):
"""
Display a menu where the key identifies the name of a function.
:param menu: dictionary, key identifies a value which is a function name
:return:
"""
for k, function in menu.items():
print(k, function.__name__)
def one():
print("you have selected menu option one")
input("Press any Enter to return to menu.")
system('cls') # clears stdout
def two():
print("you have selected menu option two")
input("Press any Enter to return to menu.")
system('cls') # clears stdout
def three():
print("you have selected menu option three")
input("Press any Enter to return to menu.")
system('cls') # clears stdout
def done():
system('cls') # clears stdout
print("Goodbye")
sys.exit()
def main():
# Create a menu dictionary where the key is an integer number and the
# value is a function name.
functions_names = [one, two, three, done]
menu_items = dict(enumerate(functions_names, start=1))
while True:
display_menu(menu_items)
selection = int(
input("Please enter your selection number: ")) # Get function name
selected_value = menu_items[selection] # Gets the function name
selected_value() # add parentheses to call the function
if __name__ == "__main__":
main()