cannot iterate a kwargs input

Question

Heey everyone! It is my first time to post a question as I am practicing Python by myself. I am not sure if similar question has been asked, but I need some tips with using **kwargs and I look forward for a feedback from a smart, enthusisastic professional coder ;)

I created a class FastFoodChain and a method add_food that if you pass in multiple food names and prices as kwargs, they shall be added to the menu:

class FastFoodChain():

   def __init__(self, name):
       self.name = name
       self.menu = None #type is a dictionary
       print(f"{name} established! Congrats!")
    
   def add_food(self, **foods): # Add a few foods from the product
    
       for food,price in foods.items():

           if food in self.menu.keys():
               return f"{food} is already in the menu"

           else:
               #self.menu[food] = price
               self.menu.setdefault(food,price)
               return f"{food} added to the menu"

McDonalds = FastFoodChain("McDonalds")
McDonalds.menu = {'fries': 3, 'chicken_nuggets': 4, 'cheeseburger': 4.5, 'cola': 2.5, 'chicken_burger': 5}

However, this function is not iterating **foods but only Big_mac, the first argument is updated to the menu:

McDonalds.add_food(Big_Mac = 6, Spicy_chicken_burger=4)

Any suggestions could be helpful. :)) Thanks in advance. Leo

Welcome to Stack Overflow! Please take the [tour] and read [ask], which has tips like how to write a good title. Personally, I'd write something more like "Why is only the first argument being used?" It's also important to note that SO is meant to be like a reference, not a forum, so chit-chat like "I'm new here" and such should be kept to a minimum. — wjandrea, Jul 08 '22 at 20:29
BTW, instead of `self.menu = None`, it'd probably be better to pass `menu` into `__init__`, that way you won't forget to set it. You could also add type hinting instead of that comment. So, something like: `def __init__(self, name: str, menu: dict): ...`. — wjandrea, Jul 08 '22 at 20:41

vogelstein · Accepted Answer · 2022-07-08T20:38:25.990

3

The problem is that you are using the return statement, which automatically ends the function. You could simply replace the two return statements with the print function.

edited Jul 08 '22 at 20:38

answered Jul 08 '22 at 20:18

vogelstein

394
1
10

score 0 · Answer 2 · answered Jul 08 '22 at 20:20

The problem is that both if and else end with a return, so the loop will exit after the first time.

Here's a suggestion to fix that.

class FastFoodChain():
    
   def __init__(self, name):
       self.name = name
       self.menu = None #type is a dictionary
       print(f"{name} established! Congrats!")
    
   def add_food(self, **foods): # Add a few foods from the product
    
       for food,price in foods.items():

           if food in self.menu.keys():
               print(f"{food} is already in the menu")

           else:
               #self.menu[food] = price
               self.menu.setdefault(food,price)
               print(f"{food} added to the menu")

McDonalds = FastFoodChain("McDonalds")
McDonalds.menu = {'fries': 3, 'chicken_nuggets': 4, 'cheeseburger': 4.5, 'cola': 2.5, 'chicken_burger': 5}
McDonalds.add_food(Big_Mac = 6, Spicy_chicken_burger=4)
print(McDonalds.__dict__)

cannot iterate a kwargs input

2 Answers2