mit 6.0001 implement and use classes, subclasses, and class variables

classespy.py

# walk through principles of implementing and calling classes and sub/superclasses
# implement and use a class variable
class Animal(object):
  def __init__(self, age):
    assert type(age) == int
    self.age = age
    self.name = []

  def __str__(self):
    return "Hey! An Animal of age: " + str(self.age) + " years."
  
  def get_age(self):
    return self.age
  
  def set_age(self, new_age):
    self.age = new_age

  def get_name(self):
    return self.name
  
  def set_name(self, new_name):
    self.name = new_name

class Cat(Animal):
  def __str__(self):
    return 'meow meow meow'

class Person(Animal):
  def __init__(self, age, name):
    Animal.__init__(self, age)
    self.name = name
    self.friends = []
  
  def get_name(self):
    return self.name
  
  def set_name(self, new_name):
    self.name = new_name

  def get_friends(self):
    return self.friends
  
  def add_friend(self, new_friend):
    if new_friend not in self.friends:
      self.friends.append(new_friend)
    
  def speak(self):
    return "Hi, I'm " + str(self.name)
  
  def age_diff(self, other):
    diff = abs(self.age - other.age)
    return str(self.name) + " and " + str(other.name) + " have a " + str(diff) + " year gap in their ages"

  def __str__(self):
    return "Person: " + str(self.name) + ": Age: " + str(self.age)

class Student(Person):
  def __init__(self, name, age, major = "none"):
    Person.__init__(self, age, name)
    self.major = major
    self.friends = []

  def get_major(self):
    return "Major: " + str(self.major)

  def change_major(self, new_major):
    self.major = new_major

  def __str__(self):
    return "Gotta run to class."

# use the Animal class
print("Use the Animal class:")
my_animal = Animal(3)
print(my_animal)

# use the Cat subclass with no new data attributes
print("Use the Cat class:")
my_cat = Cat(1)
print(my_cat)
my_cat.set_name('fluffy')
print('The cat has a name! ' + my_cat.get_name())

# use the Person subclass with new data attributes
print('Use the Person class:')
name1 = input('A name for a Person class instance: ')
age1 = int(input('Their age (years): '))
p1 = Person(age1, name1)
print(p1)
print(p1.speak())
name2 = input('A name for another Person: ')
age2 = int(input('Their age (years): '))
p2 = Person(age2, name2)
print(p2)
print(p2.speak())
p1.add_friend('Sasha')
print(str(p1.get_name()) + "\'s friends are: "+ str(p1.get_friends()))
p2_friends = list(input(f'list some friends for {p2.get_name()} (spaces between names): \n').split(" "))
for friend in p2_friends:
  p2.add_friend(friend)
print(str(p2.get_name()) + "\'s friends are: "+ str(p2.get_friends()))
print(p1.age_diff(p2))

# use the student subsubclass with new data attributes
print("Use the Student subclass of Person:")
genius = Student('Leah', 20, 'comp sci')
print('New student: ' + str(genius.get_name() + ': Age: ' + str(genius.age) + ': Major: ' + str(genius.major)))
new_major = input('Let\'s change major to: ')
genius.change_major(new_major)
print('Changed major to: ' + str(genius.major))
print(genius)