python

第一部分：基础语法

1. 变量的定义与使用

• name = "John"
• age = 25

2. 数据类型操作

• num1 = 10
• num2 = 5
• result = num1 + num2
• print(result)

3. 条件语句

• score = 85
• if score >= 90:
• print("优秀")elif score >= 80:
• print("良好")else:
• print("及格")

4. 循环结构

• for i in range(1, 6):
• print(i)

第二部分：函数和模块

1. 函数的定义与调用

• def add(a, b):
• return a + bresult = add(3, 4)
• print(result)

2. 参数传递

• def greet(name):
• print("Hello, " + name)
• greet("Alice")

3. 创建和使用模块

• # math_utils.py
• def square(num):
• return num ** 2

• # main.py
• import math_utilsresult = math_utils.square(5)print(result)

第三部分：面向对象编程

1. 类的定义和使用

class Person:    def __init__(self, name):        self.name = name

    def greet(self):        print("Hello, my name is " + self.name)

person = Person("John")person.greet()

2. 对象的创建和操作

class Circle:    def __init__(self, radius):        self.radius = radius    def area(self):        return 3.14 * self.radius ** 2circle = Circle(5)print(circle.area())

3. 继承和多态

class Animal:    def sound(self):        pass

class Dog(Animal):    def sound(self):        print("Woof!")

class Cat(Animal):    def sound(self):        print("Meow!")

dog = Dog()cat = Cat()dog.sound()cat.sound()

第四部分：文件操作

1. 读取文件

with open("data.txt", "r") as file:    data = file.read()    print(data)

2. 写入文件

with open("output.txt", "w") as file:    file.write("Hello, World!")

第五部分：异常处理

1. 捕获和处理异常

try:    num = 10 / 0except ZeroDivisionError:    print("Cannot divide by zero.")

2. 优雅地处理错误

def divide(a, b):    try:        result = a / b    except ZeroDivisionError:        result = None    finally:        return resultprint(divide(10, 2))print(divide(10, 0))

第六部分：数据结构和算法

1. 列表操作

numbers = [1, 2, 3, 4, 5]print(len(numbers))print(numbers[2])

2. 字典操作

person = {"name": "John", "age": 25}print(person["name"])print(person.get("age"))

3. 排序算法

numbers = [5, 2, 8, 1, 9]numbers.sort()print(numbers)

第七部分：网络编程

1. Socket编程

import socket

server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)server_socket.bind(("localhost", 8080))server_socket.listen(1)

client_socket, address = server_socket.accept()print("Connection from: " + str(address))client_socket.close()server_socket.close()

2. HTTP协议应用

import requestsresponse = requests.get("https://www.example.com")print(response.text)

第八部分：数据库编程

1. 访问数据库

import sqlite3connection = sqlite3.connect("database.db")cursor = connection.cursor()cursor.execute("SELECT * FROM students")data = cursor.fetchall()for row in data:    print(row)connection.close()