AttributeError: 'str' object has no attribute 'size'

[russoj5]

Hi All,

I'm doing a homework assignment and getting some errors when running the doctest. Everything seems to work fine when I manually enter data, but when I run the doctest, I am getting the same 3 errors.

This is the code that I have written for the homework assignment:

#   Pizza()

# **** COMPOSITION ******

class Pizza():
        
    #__init__  *****MODIFY METHOD******

    def __init__(self, s='M', t={}):
        #print('__init__')
        self.size = s
        self.toppings = set(t)
        

    #__repr__    *****RETURN METHOD******

    def __repr__(self):

        return f"Pizza('{self.size}',{self.toppings})"


    #__eq__    ******RETURN METHOD*****

    def __eq__(self,other):

        return self.size == other.size and self.toppings == other.toppings      

    #__setSize__  ****MODIFY METHOD******

    def setSize(self,s):
        self.size = s

    #__getSize__ *****RETURN METHOD*******

    def getSize(self):

        return self.size

    #__addTopping__    ******MODIFY METHOD*****

    def addTopping(self,t):

        #Error - str does not have "add"
        #why is it being passed a string??
            
        self.toppings.add(t)

    #__removeTopping__*****MODIFY METHOD*******

    def removeTopping(self, t):
        
        self.toppings.discard(t)
        

    #__price__    ****** RETURN METHOD ******


    def price(self):

        costDict={'S':0.70,'M':1.45,'L':1.85}

        if self.size == 'S':

            return 6.25 + costDict.get(self.size) * len(self.toppings)
            
        
        elif self.size == 'M':
            
            return 9.95 + costDict.get(self.size) * len(self.toppings)
        else:

            return 12.95 + costDict.get(self.size) * len(self.toppings)
        
            
def orderPizza():
    
    print('Welcome to Python Pizza!')
    #print(input('What size pizza would you like (S,M,L): '))# check that it receives input

    size = input('What size pizza would you like (S,M,L): ')
    #print(p.setSize)

    p=Pizza(size,t={})

    while True:

        newTopping = input('Type of topping to add (or Enter quit): ')
        #print(p)


        if newTopping == '':
            break
        else:
            p.addTopping(newTopping)
            #print(p)
    
    
    print('Thanks for ordering!')
    
    return f"Your pizza costs ${p.price()})"



if __name__=='__main__':
    import doctest
    print( doctest.testfile( 'hw8TEST.py'))

This is the doctest code that is running and causing the errors:

##### orderPizza #####
>>> orderPizza()==Pizza('M',{'garlic', 'onion', 'mushroom'})
Welcome to Python Pizza!
What size pizza would you like (S,M,L): Type topping to add (or Enter to quit): Type topping to add (or Enter to quit): Type topping to add (or Enter to quit): Type topping to add (or Enter to quit): Thanks for ordering!
Your pizza costs $14.299999999999999
True
>>> orderPizza()==Pizza('L',{'calamari', 'garlic'})
Welcome to Python Pizza!
What size pizza would you like (S,M,L): Type topping to add (or Enter to quit): Type topping to add (or Enter to quit): Type topping to add (or Enter to quit): Thanks for ordering!
Your pizza costs $16.65
True
>>> orderPizza()==Pizza('S',set())
Welcome to Python Pizza!
What size pizza would you like (S,M,L): Type topping to add (or Enter to quit): Thanks for ordering!
Your pizza costs $6.25
True

#stdin back #

put stdin back to original, again, shouldnt cause error
>>> sys.stdin = si  # return stdin

This is the typical error:

Output:
File "/Users/jamesrusso/Desktop/DePaul/CSC 401 Introduction to Programming/Week 8/hw8TEST.py", line 77, in hw8TEST.py
Failed example:
    orderPizza()==Pizza('M',{'garlic', 'onion', 'mushroom'})
Exception raised:
    Traceback (most recent call last):
      File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/doctest.py", line 1336, in __run
        exec(compile(example.source, filename, "single",
      File "<doctest hw8TEST.py[26]>", line 1, in <module>
        orderPizza()==Pizza('M',{'garlic', 'onion', 'mushroom'})
      File "/Users/jamesrusso/Desktop/DePaul/CSC 401 Introduction to Programming/Week 8/hw8.py", line 32, in __eq__
        return self.size == other.size and self.toppings == other.toppings
    AttributeError: 'str' object has no attribute 'size'

It looks like it doesnt like the __eq__ function in the Pizza() class. I've been playing around with it for a few hours and not sure what I'm doing wrong. I'm at the point where I've been guessing at different solutions without any real reason for trying them and feel like I don't have a good enough understanding of the material at this point because I'm stuck.

Any suggestions on what I should look at or hints to get me moving in the right direction would be very helpful and appreciated.

[deanhystad]

This is the test:

orderPizza()==Pizza('M',{'garlic', 'onion', 'mushroom'})

orderPizza returns a string:

def orderPizza():
    - snip - 
    return f"Your pizza costs ${p.price()})"

And this returns a Pizza object:

Pizza('M',{'garlic', 'onion', 'mushroom'})

A Pizza object and a string will never be equal, so this test will always fail. This particular fail occurs when the Pizza.__eq__ metnod tries to compare the Pizza.size to str.size. str does not have an attribute named "size", so this throws an error.

You need to change the orderPizza function to return a Pizza.

[russoj5]

Thank you for your help! I updated the function to return the pizza and the code works now.

[russoj5]

This is the test:

orderPizza()==Pizza('M',{'garlic', 'onion', 'mushroom'})

orderPizza returns a string:

def orderPizza():
    - snip - 
    return f"Your pizza costs ${p.price()})"

And this returns a Pizza object:

Pizza('M',{'garlic', 'onion', 'mushroom'})

A Pizza object and a string will never be equal, so this test will always fail. This particular fail occurs when the Pizza.__eq__ metnod tries to compare the Pizza.size to str.size. str does not have an attribute named "size", so this throws an error.

You need to change the orderPizza function to return a Pizza.

I was fixated on the __eq__ line of the error thinking it was an issue with that code in the Class. I wouldn't have thought to look at what I was returning from the orderPizza function. This was a humbling but valuable experience.

[deanhystad]

The line where the error is reported is only the line where the error raises an exception. The error usually occurs earlier and elsewhere.