Python Tutorials
Python Introduction
Python Get Started
Python Syntax
Python Comments
Python Variables
Python Data Types
Python Casting
Python Strings
Python Booleans
Python Operators
Python Lists
Python Tuples
Python Sets
Python Dictionaries
Python If...Else
Python While Loops
Python For Loops
Python Functions
Python Lambda
Python Arrays
Python Classes/Objects
Python Inheritance
Python Iterators
Python Scope
Python Modules
Python Dates
Python Math
Python JSON
Python RegEx
Python PIP
Python Try..Except
Python User Input
Python String Formatting
Python File Handling
Python File Handling
Python Read Files
Python Create/Write Files
Python Delete Files
Python Modules
Python Numpy
Python Pandas
Python SciPy
Previous
Python Classes and Objects
Python Classes/Objects
Python is an object-oriented programming language.
Almost everything in Python is an object, with its structures and methods.
A class is like an architect, or a "plan" for creating things.
Create a Class
To create a class, use the keywords class:
Example
Create a class named MyClass, with a property named x:
class MyClass:
x = 5
Create Object
We can now use a class called MyClass to create objects:
Example
Create an object named p1, and print the value of x:
p1 = MyClass()
print(p1.x)
The __init__() Function
The examples above are classes and objects in their simplest form, and are not really helpful in real-life applications.
To understand the meaning of classes we must understand __init __ () the built-in function.
All classes have a function called __init __ (), which is used every time a class is started.
Use the __init __ () function to assign values to object properties, or other functions that need to be performed when an object is created:
Example
Create a class named Person, use the __init__() function to assign values for name and age:
class Person:
def __init__(self, name, age):
self.name = name
self.age = age
p1 = Person("John",
36)
print(p1.name)
print(p1.age)
Note: The __init__ () function is automatically called every time a class is used to create something new.
Object Methods
Items may contain paths. Methods in objects are functions that are part of an object.
Let's build a path in the Classroom:
Example
Insert a function that prints a greeting, and execute it on the p1 object:
class Person:
def __init__(self, name, age):
self.name = name
self.age = age
def myfunc(self):
print("Hello my name is " + self.name)
p1 = Person("John",
36)
p1.myfunc()
Note: The self parameter itself is a reference to the current class model, and is used for class flexible access.
The self Parameter
The self parameter itself is a reference to the current class model, and is used for class flexible accessibility.
It doesn't have to be named self, you can call it whatever you like, but it should be the first parameter of any class activity:
Example
Use the words mysillyobject and abc instead of self:
class Person:
def __init__(mysillyobject, name, age):
mysillyobject.name = name
mysillyobject.age = age
def myfunc(abc):
print("Hello my name is " + abc.name)
p1 = Person("John",
36)
p1.myfunc()
Modify Object Properties
You can change the properties for things like:
Example
Set the age of p1 to 40:
p1.age = 40
Delete Object Properties
You can remove structures from objects by using the keyword del:
Example
Delete the age property from the p1 object:
del p1.age
Delete Objects
You can delete items by using the keyword del:
Example
Delete the p1 object:
del p1
The pass Statement
class descriptions can not be empty, but if for some reason you have a class description that does not contain content, include a pass statement to avoid finding an error.
Example
class Person:
pass