Question

Python 3+

Adjust the following code so the two errors below are non-present:

1. __init__() : Since Pizza object don't have it's own set() datastructure, the toppings in the pizza object are manimupated from out of the object. (-1.0)
2. __eq__() : How about "self.toppings == other.toppings" rather than "self.toppings - other.toppin == set())".

Code:

## Program 1
## ---------------------------------

class Pizza:
def __init__(self, s='M', top=set()):
self.setSize(s)
self.toppings = top

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

def getSize(self):
return self.size

def addTopping(self, top):
self.toppings.add(top)

def removeTopping(self, top):
self.toppings.remove(top)

def price(self):
if self.size == 'S':
return 6.25 + (0.7 * len(self.toppings))
elif self.size == 'M':
return 9.95 + (1.45 * len(self.toppings))
else:
return 12.95 + (1.85 * len(self.toppings))

def __repr__(self):
end = 'Pizza('
end += ('\'' + self.size + '\'')
end += ','
end += str(self.toppings)
end += ')'
return end

def __eq__(self, other):
return self.size == other.size and (self.toppings - other.toppings == set ())

## Program 2
## ---------------------------------

def orderPizza():
print('Welcome to Python Pizza!')
size = input('What size pizza would you like (S,M,L): ')
za = Pizza(size, set())
while True:
topping = input('Type topping to add (or Enter to quit): ')
if topping == '':
break
else:
za.addTopping(topping)
print('Thanks for ordering!')
print('Your pizza costs $' + str(za.price()))
return za

Answer 1

CODE

==============

## Program 1

## ---------------------------------

class Pizza:

def __init__(self, s='M', top=set()):

self.setSize(s)

self.toppings = top

def setSize(self, s):

self.size = s

def getSize(self):

return self.size

def addTopping(self, top):

self.toppings.add(top)

def removeTopping(self, top):

self.toppings.remove(top)

def price(self):

if self.size == 'S':

return 6.25 + (0.7 * len(self.toppings))

elif self.size == 'M':

return 9.95 + (1.45 * len(self.toppings))

else:

return 12.95 + (1.85 * len(self.toppings))

def __repr__(self):

end = 'Pizza('

end += (''' + self.size + ''')

end += ','

end += str(self.toppings)

end += ')'

return end

def __eq__(self, other):

return self.size == other.getSize() and (self.toppings == other.toppings)

## Program 2

## ---------------------------------

def orderPizza():

print('Welcome to Python Pizza!')

size = input('What size pizza would you like (S,M,L): ')

za = Pizza(size, set())

while True:

topping = input('Type topping to add (or Enter to quit): ')

if topping == '':

break

else:

za.addTopping(topping)

print('Thanks for ordering!')

print('Your pizza costs $' + str(za.price()))

return za

pizza1 = orderPizza()

pizza2 = orderPizza()

print(pizza1 == pizza2)

Answer 2

1. Regarding the init() method: The statement "Since Pizza object doesn't have its own set() data structure, the toppings in the pizza object are manipulated from outside the object" is incorrect. The Pizza object does have its own set() data structure for storing the toppings, and the toppings are manipulated within the object itself. The line self.toppings = top in the init() method initializes the toppings attribute of the Pizza object with the provided set of toppings.

2. Regarding the eq() method: You are correct that a simpler and more direct way to compare the toppings of two Pizza objects is by using self.toppings == other.toppings instead of self.toppings - other.toppings == set(). The equality check self.toppings == other.toppings compares the sets directly to determine if they contain the same elements. The expression self.toppings - other.toppings == set() checks if the set difference between the two toppings sets is an empty set, indicating that they have the same elements.

Using self.toppings == other.toppings is a clearer and more concise way to express the intention of comparing the toppings. The modified eq() method would be as follows:

pythonCopy codedef __eq__(self, other):    return self.size == other.size and self.toppings == other.toppings

This updated implementation directly compares the sizes and toppings of the two Pizza objects, ensuring that both attributes match for the objects to be considered equal.