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Python Classes and ObjectsPython Classes/ObjectsPython is an object oriented programming language. Show
Almost everything in Python is an object, with its properties and methods. A Class is like an object constructor, or a "blueprint" for creating objects. Create a ClassTo create a class, use the keyword ExampleCreate a class named MyClass, with a property named x: class
MyClass: Try it Yourself » Create ObjectNow we can use the class named MyClass to create objects: ExampleCreate an object named p1, and print the value of x: p1 = MyClass() Try it Yourself » The __init__() FunctionThe examples above are classes and objects in their simplest form, and are not really useful in real life applications. To understand the meaning of classes we have to understand the built-in __init__() function. All classes have a function called __init__(), which is always executed when the class is being initiated. Use the __init__() function to assign values to object properties, or other operations that are necessary to do when the object is being created: ExampleCreate a class named Person, use the __init__() function to assign values for name and age: class Person: p1 = Person("John", 36) print(p1.name) Try it Yourself » Note:
The The __str__() FunctionThe __str__() function controls what should be returned when the class object is represented as a string. If the __str__() function is not set, the string representation of the object is returned: ExampleThe string representation of an object WITHOUT the __str__() function: class Person: p1 = Person("John", 36) print(p1) Try it Yourself » ExampleThe string representation of an object WITH the __str__() function: class Person: def __str__(self): p1 = Person("John", 36) print(p1) Try it Yourself » Object MethodsObjects can also contain methods. Methods in objects are functions that belong to the object. Let us create a method in the Person class: ExampleInsert a function that prints a greeting, and execute it on the p1 object: class Person: def myfunc(self): p1 = Person("John", 36) Try it Yourself » Note:
The The self ParameterThe It does not have to be named ExampleUse the words mysillyobject and abc instead of self: class Person: def myfunc(abc): p1 = Person("John", 36) Try it Yourself » Modify Object PropertiesYou can modify properties on objects like this: Delete Object PropertiesYou can delete properties on objects by using the Delete ObjectsYou can delete objects by using the The pass Statement
Test Yourself With ExercisesLearn PythonPython is a popular programming language. Python can be used on a server to create web applications. Start learning Python now » Learning by ExamplesWith our "Try it Yourself" editor, you can edit Python code and view the result. Click on the "Try it Yourself" button to see how it works. Python File HandlingIn our File Handling section you will learn how to open, read, write, and delete files. Python File Handling Python Database HandlingIn our database section you will learn how to access and work with MySQL and MongoDB databases: Python MySQL Tutorial Python MongoDB Tutorial Python ExercisesTest Yourself With ExercisesExercise:Insert the missing part of the code below to output "Hello World". Start the Exercise Python ExamplesLearn by examples! This tutorial supplements all explanations with clarifying examples. See All Python Examples Python QuizTest your Python skills with a quiz. Python Quiz My LearningTrack your progress with the free "My Learning" program here at W3Schools. Log into your account, and start earning points! This is an optional feature. You can study W3Schools without using My Learning.
Python ReferenceYou will also find complete function and method references: Reference Overview Built-in Functions String Methods List/Array Methods Dictionary Methods Tuple Methods Set Methods File Methods Python Keywords Python Exceptions Python Glossary Random Module Requests Module Math Module CMath Module Download PythonDownload Python from the official Python web site: https://python.org Kickstart your careerGet certified by completing the course Get certified w3schoolsCERTIFIED.2022 |