How to loop conditional statements based on specific user input in Python?

Question

For example, in this sample code,

greeting = input("What's your favorite cheese?")
if greeting == "cheddar":
    print("Mine too!")

elif greeting == "bleu cheese":
    print("Gross!")

elif greeting == "parmesan":
    print("Delicious!")

else:
    cheese = input("That's not a cheese, try again!")
    cheese == greeting

if I input "Mozzarella" as 'greeting', I would like it to prompt me with "That's not a cheese" and also let me re-input a value for 'greeting' until cheddar, bleu cheese, or parmesan is entered, if that makes any sense. I have a larger program I am working on for class that involves multiple conditional statements nested within each other, and for each 'set' of statements I'd like to be able to print an error message when the user inputs an invalid entry and allow them to try again without having to restart the program.

Also you might want to construct a dict with valid cheeses and your responses. It would make the code easier to manage. — Jason Sperske
– Jason Sperske, Commented Mar 10, 2015 at 19:52

A.J. Uppal · Accepted Answer · 2015-03-10 21:38:10Z

3

Try the following

greeting = input("What's your favorite cheese?") #Get input
while greeting not in ['cheddar', 'blue cheese', 'parmesan']: #Check to see if the input is not a cheese
    greeting = input("That's not a cheese, try again!")
else: #If it is a cheese, proceed
    if greeting == "cheddar":
        print("Mine too!")

    elif greeting == "bleu cheese":
        print("Gross!")

    elif greeting == "parmesan":
        print("Delicious!")

    else:
        cheese = input("That's not a cheese, try again!")

What's your favorite cheese? peanut butter
That's not a cheese, try again! ketchup
That's not a cheese, try again! parmesan
Delicious!

edited Mar 10, 2015 at 21:38

answered Mar 10, 2015 at 19:54

A.J. Uppal

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2 Comments

MikeVaughan Over a year ago

I still think using a dictionary is a better idea for this. But this definitely works.

A.J. Uppal Over a year ago

@MikeVaughan true enough, it saves some lines of code, but I don't want to change the OP's code unless called for.

dursk · Accepted Answer · 2015-03-10 19:51:19Z

3

greeting = ''
while greeting not in ['cheddar', 'blue cheese', 'parmesan']:
    greeting = input("That's not a cheese, try again!")

answered Mar 10, 2015 at 19:51

dursk

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Comments

MikeVaughan · Accepted Answer · 2015-03-10 20:17:25Z

2

Build a dict with your responses to each cheese, with the names of the cheeses as the keys. The use a while loop.

cheeses = {'bleu cheese':'Gross!','cheddar':'Mine Too!','parmesan':'Delicous!'}

greeting = input("What's your favorite cheese?")

while greeting not in cheeses:
    print "That's not a Cheese! Try Again!"
    greeting = input("Whats your favorite cheese?")


print cheeses[greeting]

answered Mar 10, 2015 at 20:17

MikeVaughan

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1 Comment

heemayl Over a year ago

this is better that recursive if-else

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