Python classes and objects study guide: from basics to practice

1. Basic knowledge of classes and objects

1. Class: A class is the template of an object, describing the properties and methods of the object.

2. Object: An object is an instance of a class and has the properties and methods described by the class.

3. Instantiation: The process of creating an object is called instantiation.

2. Definition and use of classes

1. Class definition: Use the class keyword to define a class.

2. Attributes: Attributes are member variables of the class and are used to describe the characteristics of the object.

3. Methods: Methods are member functions of a class and are used to implement the business logic of the object.

3. Creation and use of objects

1. Object creation: Use class name () to create objects.

2. Property access: Use the dot operator (.) to access the properties of the object.

3. Method call: Use the dot operator (.) to call the object's method.

4. Inheritance and Polymorphism

1. Inheritance: Subclasses can inherit the properties and methods of the parent class.

2. Polymorphism: The methods of the parent class and the subclass have the same method name, but different implementations.

5. Encapsulation

1. Encapsulation: Encapsulation refers to hiding the properties and methods of an object and exposing only the necessary interfaces to the outside world.

2. Benefits of encapsulation: Improve code maintainability, security, and reusability.

6. Demo code

# 定义一个类
class Person:
def __init__(self, name, age):
self.name = name
self.age = age

def say_hello(self):
print("Hello, my name is {} and I am {} years old.".fORMat(self.name, self.age))

# 创建一个对象
person = Person("John", 30)

# 访问对象的属性
print("Name:", person.name)
print("Age:", person.age)

# 调用对象的方法
person.say_hello()

7. Summary

Classes and objects are very important concepts in python. By learning classes and objects, we can better understand and write Python programs. I hope this article can help you learn the basics of classes and objects and be able to apply them in actual development.

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