Objects and Classes in Python

Creating a Class

• Begin with defining a class, e.g., class Guitar:
• Use the __init__ method to initialize class attributes.

  def __init__(self, self):
      self.n_strings = 6
  

• Access these attributes by creating an object.

  my_guitar = Guitar()
  print(my_guitar.n_strings)  # Outputs: 6
  

Methods in Classes

• Methods add functionality to classes.

  def play(self):
      print('🎶')
  

• Call methods on an object.

  my_guitar.play()  # Outputs: 🎶
  

• Automatically call a method within the __init__ method.

  def __init__(self, self):
      self.n_strings = 6
      self.play()
  

Inheritance

• Create a new class that inherits from an existing class.

  class ElectricGuitar(Guitar):
      pass
  

• Add or override methods and attributes.

  class ElectricGuitar(Guitar):
      def play_louder(self):
          print('🎶'.upper())
  

• Use the super() function to access parent methods.

  def __init__(self, self):
      super().__init__()
      self.n_strings = 8
  

Private Members

• Use double underscores to make members private.

  self.__cost = 50
  print(my_guitar.__cost)  # Error
  

• Access private members through class name.

  print(my_guitar._ElectricGuitar__cost)  # Works
  

Adding New Attributes

• Modify __init__ method to accept new attributes.

  def __init__(self, self, n_strings=6):
      self.n_strings = n_strings
  

• Create another class with minimal code repetition.

  class BassGuitar(Guitar):
      pass
  

Example Summary

• Created classes and methods
• Showed inheritance and adding/updating methods and attributes
• Discussed private members and their limitations in Python
• Demonstrated how to avoid code repetition using parameters with default values

Conclusion

• Practice more with the