[Python learning] Object-oriented programming
Process-oriented programming regards a computer program as a series of command sets, that is, the sequential execution of a set of functions. In order to simplify programming, process-oriented functions are continued to be divided into sub-functions, that is, large functions are cut into small functions to reduce the complexity of the system.
Python and java are both object-oriented languages. Characteristics of object-oriented programmingData encapsulation, inheritance and polymorphism
1. Classes and instances
The most important concepts of object-oriented programming are classes and instances ), you must remember that a class is an abstract template, such as the Student class, and instances are specific "objects" created based on the class. Each object has the same methods, but their data may be different.
In python, the class keyword is also used to define a class. Class is followed by the class name, which needs to be capitalized at the beginning. The brackets after it indicate which class it inherits, that is, its parent class.
class Student(object): pass
We can freely bind attributes to this variable
>>>nick.name = 'Liu Ling Hao' >>>nick.name 'Liu Ling Hao'
The different functions defined later are methods. In summaryObject = Attribute Method
Because classes can function as templates, when creating an instance, we can forcefully fill in some attributes that we think must be bound. At this time, you need to use the more special __init__ method. (There are two underscores before and after int) The first parameter of the
__init__ method is always self, which represents the created instance itself.
class Student(object): def __init__(self, name, score): self.name = name self.score = scor >>> bart = Student('Bart Simpson', 59) >>> bart.name 'Bart Simpson' >>> bart.score 59
When you have the __init__ method, you cannot pass in empty parameters when creating an instance. You must pass in parameters that match the __init__ method
2. Encapsulation, inheritance and polymorphism
An important feature of object-oriented programming is data encapsulation.
Just like name and score in the above example, we can access it directly through functions defined inside the class. For example, we can add a piece of data or sort a list. We can implement it, but we don't know it. The interior is achieved through how it is adjusted.
When we define a class, we can inherit from an existing class. The new class is called a subclass (Subclass), and the inherited class is called a base class or a parent class. Or super class (Base class, Super class).
The advantage of inheritance is that you get all the functions of the parent class. For subclasses, you can continue to write on the basis of the parent class, which is more convenient.
class Person(object): def idea(self): print('study is happy')class Liu(Person): pass liu =Liu()liu.idea study is happy
Of course, if the subclass When there is the same method as the parent class, it will automatically override the parent class's
Polymorphism: different objects respond to different actions for the same method
>>>class Nick1: def name(self): print("我是1") >>>class Nick2: def name(self): print("我是2") >>>a = Nick1() >>>b = Nick2() >>>a.name 我是1 >>>b.name 我是2
Although the function names used are the same, the implementations are different Same.
def run(animal): animal.run() animal.run() >>> run(Animal()) Animal is running... Animal is running... >>> run_twice(Dog()) Dog is running... Dog is running...
The advantage of polymorphism is that when we need to pass in Dog or other animals, we only need to receive the Animal type, because Dogs are all Animal types, and then operate according to the Animal type. . Since the Animal type has a run() method, any type passed in, as long as it is an Animal class or subclass, will automatically call the run() method of the actual type. This is polymorphism.
[Recommended course: Python video tutorial]
The above is the detailed content of [Python learning] Object-oriented programming. For more information, please follow other related articles on the PHP Chinese website!

Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics





PHP is suitable for web development and rapid prototyping, and Python is suitable for data science and machine learning. 1.PHP is used for dynamic web development, with simple syntax and suitable for rapid development. 2. Python has concise syntax, is suitable for multiple fields, and has a strong library ecosystem.

PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.

VS Code can be used to write Python and provides many features that make it an ideal tool for developing Python applications. It allows users to: install Python extensions to get functions such as code completion, syntax highlighting, and debugging. Use the debugger to track code step by step, find and fix errors. Integrate Git for version control. Use code formatting tools to maintain code consistency. Use the Linting tool to spot potential problems ahead of time.

VS Code can run on Windows 8, but the experience may not be great. First make sure the system has been updated to the latest patch, then download the VS Code installation package that matches the system architecture and install it as prompted. After installation, be aware that some extensions may be incompatible with Windows 8 and need to look for alternative extensions or use newer Windows systems in a virtual machine. Install the necessary extensions to check whether they work properly. Although VS Code is feasible on Windows 8, it is recommended to upgrade to a newer Windows system for a better development experience and security.

VS Code extensions pose malicious risks, such as hiding malicious code, exploiting vulnerabilities, and masturbating as legitimate extensions. Methods to identify malicious extensions include: checking publishers, reading comments, checking code, and installing with caution. Security measures also include: security awareness, good habits, regular updates and antivirus software.

In VS Code, you can run the program in the terminal through the following steps: Prepare the code and open the integrated terminal to ensure that the code directory is consistent with the terminal working directory. Select the run command according to the programming language (such as Python's python your_file_name.py) to check whether it runs successfully and resolve errors. Use the debugger to improve debugging efficiency.

PHP originated in 1994 and was developed by RasmusLerdorf. It was originally used to track website visitors and gradually evolved into a server-side scripting language and was widely used in web development. Python was developed by Guidovan Rossum in the late 1980s and was first released in 1991. It emphasizes code readability and simplicity, and is suitable for scientific computing, data analysis and other fields.

Python is more suitable for beginners, with a smooth learning curve and concise syntax; JavaScript is suitable for front-end development, with a steep learning curve and flexible syntax. 1. Python syntax is intuitive and suitable for data science and back-end development. 2. JavaScript is flexible and widely used in front-end and server-side programming.
