timwebster85 / python-oop

Object Oriented Programming with Python

Object Oriented Programming with Python

https://www.youtube.com/watch?v=Ej_02ICOIgs&ab_channel=freeCodeCamp.org

Notes

• Classes should have the first letter as a capital

• anything that starts with __ is called a "magic method"

• you can assign value to parm by given a default value def __init__(self, name, price, qty=0):

• to force a data type use : after varible name example def __init__(self, name: str, price: float, qty=0):

  • fact that we have assigned a default value of an int in qty tells python the date type it must use

• assert keyword check what is happening to your expectations

• asserts allow you to add better error handling easily

• Class attributes are shared belongs to the class itself

• instance attribute are only for the instance of that class

• __dict__ all the attribute for Class level and instance level. This is useful for debugging

• __repr__ is a magic method - representing your objects

  • it is best practise to name the items the same format as when you call the class return f"Item('{self.name}, {self.price}, {self.qty}')" = Item('Phone', 100, 5)
  • a special method used to represent a class's objects as a string.

• 

• @classmethod using this converts function into a class method

• cls loads the class itself

• @staticmethod static mehtod should do some work for you that has some logical connection to a class

  • a static method is bound to a class rather than the objects for that class

• Parent and child classes

• 

• super functions allows us to use functionality from parent class

• self.__class__.__name__ allows you to see the name of the class in a parent child situation

• Encapsulation - describes the concept of bundling data and methods within a single unit

• Decorators are like another function that you pre execute before another function

• Puttig 2 __ infornt of a variable or attribute makes it a "private" atrribute

• @property decorator makes things read only

• @name.setter used t change variables that are read only

  • https://www.geeksforgeeks.org/getter-and-setter-in-python/

• Encapsulation - Restricting directed action to attributes of program

  • using __
  • you don't allow access directly to an attribut you modify using a method
  • Check apply_increment and apply_discount functions

• Abstraction - only show the nessary atrrib hide the unnessary details from users

  • hide unnessary info from instances i.e the email sending example
  • use __ double underscore to hide the functions \ methods

• Inheritance - Inheritance is the capability of one class to derive or inherit the properties from another class.

  • Parent child stuff as above

• Polymorphism - abilite to have diff scenarios The word polymorphism means having many forms. In programming, polymorphism means the same function name (but different signatures) being used for different types.

  • https://www.geeksforgeeks.org/polymorphism-in-python/