Need a menu divider that always matches its title? Use len(). It returns the number of characters in a string or items in a container. section 3.0
Try it in the REPL
Type len('abcd') to get 4. It also works through variables: len('hello') gives 5, and len([1, 2, 3]) gives 3. Combine it with string repetition: len('hello') * '-' produces '-----'. section 3.0
In a menu function, print(len(title) * '-') so the divider grows or shrinks with the title instead of requiring manual counting. section 3.0
Listing 3.1 The full menu program with a function
def menu(choices, title="Erik's Menu", prompt="Choose your item: "):
print(title)
print(len(title) * "-")
i = 1
for c in choices:
print(i, c)
i = i + 1
choice = input(prompt)
answer = choices[int(choice) - 1]
return answer
drinks = ["chocolate", "coffee", "decaf"]
flavors = ["caramel", "vanilla", "peppermint", "raspberry", "plain"]
toppings = ["chocolate", "cinnamon", "caramel"]
drink = menu(drinks)
flavor = menu(flavors, "Erik's flavors", "Choose your flavor: ")
topping = menu(toppings, "Erik's toppings", "Choose your topping: ")
print("Here is your order: ")
print("Main product: ", drink)
print("Flavor: ", flavor)
print("Topping: ", topping)
print("Thanks for your order!")
See the complete coffee-shop menu program using len() alongside function parameters, loops, lists, input, and return values. section 3.0
