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Lesson 8. Inheritance

Lesson Notes

Inheritance

In Python, it is possible to inherit attributes and methods from one class to another. The "inheritance concept" is categorized into two groups:

• subclass (child) - the class that inherits from another class.
• superclass (parent) - the class being inherited from.

In Python, to inherit from a class, you enter the name of the superclass into the brakets () as a parameter/.

In the following example, the P16_Student class (subclass) inherits the attributes and methods from the Student class (superclass)

class Student:
  # Private member variables (use getters/setters for access)
  __name = None
  __age = None

  def get_name(self):
     return self.name

  def set_name(self, name):
     self.name = name

  def get_age(self):
     return self.age

  def set_age(self, age):
     self.age = age

class P16_Student(Student):
    # Inherits from Student class
    pass


def main():
  stu24 = P16_Student()
  stu24.set_name("Fei")
  stu24.set_age(17)
  print(stu24.get_name(), "", str(stu24.get_age()))

main()

Fei is 17

super is used to refer to the superclass, which will send data to the constructor in the superclass to the subclass.

class Student:
  def __init__(self, name, age):
     self.name = name
     self.age = age

  def get_name(self):
     return self.name

  def set_name(self, name):
     self.name = name

  def get_age(self):
     return self.age

  def set_age(self, age):
     self.age = age

// New P16_Student Constructor has been created in this class. super is used to specify which parameters are inherited from the student superclass.

class P16_Student(Student):
  def __init__(self, name, age, ucas):
     super().__init__(name, age)
     self.ucas = ucas

  def get_ucas(self):
    return self.ucas

  def set_ucas(self, ucas):
    self.ucas = ucas

def main():
  stu24 = P16_Student("Fei", 17, False)
  print(stu24.get_name(), "is", stu24.get_age())
  print("UCAS complete: ", stu24.get_ucas())

main()

Fei is 17
UCAS complete: false