Matching dict keys with user input in python

Question

I am creating a python pizza app (yes I know there is a ton of them) but, I am coming across a scenario that I need help understanding.

price = 0

toppings = {
    'mushrooms': .5,
    'onions': .5,
    'pepperoni': 1,
    'extra-cheese':1
}

pizzaSize = {
    'small': 8,
    'medium': 10,
    'large': 12,
    'x-large': 14
}


order1 = input("Welcome to the pizza store what size pizza can we get for you (small, medium, large, or x-large): " )

print(order1)

if order1 == pizzaSize.keys():
    print(order1)

I understand that this code will not work when it comes to the if order1 part. However, I am interested in understanding how I could take the input and match it with a key of the dict pizzaSize.

Here is why I want to do that. I want to take user input and check and see if it is contained inside the pizzaSize dict.

If the string is contained there, I want to add the value of that key that matched to the price variable set at the top. Thank you all!

@azro thanks. I don't know why and when the extra argument of `None` for `get` became almost a muscle memory. — DaveIdito, Aug 16 '20 at 14:42

score 1 · Answer 1 · answered Aug 16 '20 at 14:33

1

You can do it multiple ways:

Use if order1 in pizzaSize, if it is true, add the price
Use .get() to see if the size is present in the dictionary and react accordingly.
Use pizzaSize[order1] and catch the exception if the key is not present in dict.

answered Aug 16 '20 at 14:33

Anirudh Bagri

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score 0 · Accepted Answer · edited Aug 16 '20 at 14:39

0

You need may use an .get() to get the corresponding value from the dict, if it doesn't exist you'll a None

order1 = input("Welcome to the pizza store what size pizza can we get for you (small, medium, large, or x-large): " )

size_price = pizzaSize.get(order1)
if size_price is not None:
    price += size_price
else:
    print(f"Sorry the size '{order1}' doesn't exist")
    exit(1)

edited Aug 16 '20 at 14:39

Booboo

38,656
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answered Aug 16 '20 at 14:31

azro

53,056
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File "pizzaAppv2.py", line 21, in sizePrice = pizzaSize.get(pizzaSize) TypeError: unhashable type: 'dict' that is the error you get if you do it like you said – aroe Aug 16 '20 at 14:40
@aroe there was a mistake, look again the new code – azro Aug 16 '20 at 14:41
That's a good point but I don't think it matters. Either way it's just adding the new price to the price var. However it is erroring now see above ^. – aroe Aug 16 '20 at 14:43
fixed, I passed it the new var of order1 and it output the correct price. – aroe Aug 16 '20 at 14:44
Very sorry @azro for not accepting your answer! Just did it now and it was very useful thank you so much! – aroe Aug 19 '20 at 20:28

Matching dict keys with user input in python

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