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第五天基础项目实践

article 2024/10/22 14:34:59

进行Python基础项目实践是学习和掌握Python编程的一个非常有效的方法。以下是一些适合初学者的小项目实践，旨在帮助你熟悉Python的基本语法和常见库。

1. 计算器

创建一个简单的命令行计算器，可以执行基本的算术运算（加、减、乘、除）。

def add(x, y):
    return x + y

def subtract(x, y):
    return x - y

def multiply(x, y):
    return x * y

def divide(x, y):
    if y == 0:
        return "Error! Division by zero."
    return x / y

print("Select operation:")
print("1. Add")
print("2. Subtract")
print("3. Multiply")
print("4. Divide")

choice = input("Enter choice(1/2/3/4): ")

num1 = float(input("Enter first number: "))
num2 = float(input("Enter second number: "))

if choice == '1':
    print(f"{num1} + {num2} = {add(num1, num2)}")
elif choice == '2':
    print(f"{num1} - {num2} = {subtract(num1, num2)}")
elif choice == '3':
    print(f"{num1} * {num2} = {multiply(num1, num2)}")
elif choice == '4':
    print(f"{num1} / {num2} = {divide(num1, num2)}")
else:
    print("Invalid Input")

2. 天气预报应用

使用OpenWeatherMap API来获取特定城市的天气信息。

步骤：

注册一个OpenWeatherMap账户并获取API密钥。
使用requests库来发送HTTP请求。
解析返回的JSON数据并显示天气信息。

import requests

def get_weather(city, api_key):
    url = f"http://api.openweathermap.org/data/2.5/weather?q={city}&appid={api_key}&units=metric"
    response = requests.get(url)
    data = response.json()

    if response.status_code == 200:
        main = data['main']
        weather = data['weather'][0]
        print(f"City: {city}")
        print(f"Temperature: {main['temp']}°C")
        print(f"Humidity: {main['humidity']}%")
        print(f"Weather: {weather['description']}")
    else:
        print("Error in the HTTP request")

api_key = "YOUR_API_KEY"
city = input("Enter city name: ")
get_weather(city, api_key)

3. 简单的Web爬虫

编写一个简单的网页爬虫，从指定网页中提取特定信息（如标题、链接等）。

import requests
from bs4 import BeautifulSoup

def fetch_webpage(url):
    response = requests.get(url)
    if response.status_code == 200:
        return response.text
    else:
        return None

def parse_webpage(html_content):
    soup = BeautifulSoup(html_content, 'html.parser')
    title = soup.title.string if soup.title else "No Title"
    links = [a.get('href') for a in soup.find_all('a', href=True)]
    return title, links

url = input("Enter URL: ")
html_content = fetch_webpage(url)
if html_content:
    title, links = parse_webpage(html_content)
    print(f"Title: {title}")
    print("Links:")
    for link in links:
        print(link)
else:
    print("Failed to fetch webpage")

4. To-Do List应用

创建一个简单的命令行To-Do List应用，允许用户添加、查看和删除任务。

import json

def load_tasks():
    try:
        with open('tasks.json', 'r') as file:
            tasks = json.load(file)
    except FileNotFoundError:
        tasks = []
    return tasks

def save_tasks(tasks):
    with open('tasks.json', 'w') as file:
        json.dump(tasks, file, indent=4)

def add_task(tasks):
    task = input("Enter task: ")
    tasks.append(task)
    save_tasks(tasks)
    print("Task added!")

def view_tasks(tasks):
    if not tasks:
        print("No tasks to show.")
    else:
        for i, task in enumerate(tasks, start=1):
            print(f"{i}. {task}")

def delete_task(tasks):
    view_tasks(tasks)
    try:
        choice = int(input("Enter task number to delete: "))
        if 1 <= choice <= len(tasks):
            tasks.pop(choice - 1)
            save_tasks(tasks)
            print("Task deleted!")
        else:
            print("Invalid choice.")
    except ValueError:
        print("Invalid input.")

def main():
    tasks = load_tasks()
    while True:
        print("\n1. Add Task")
        print("2. View Tasks")
        print("3. Delete Task")
        print("4. Exit")
        choice = input("Enter choice: ")

        if choice == '1':
            add_task(tasks)
        elif choice == '2':
            view_tasks(tasks)
        elif choice == '3':
            delete_task(tasks)
        elif choice == '4':
            break
        else:
            print("Invalid choice. Please try again.")

if __name__ == "__main__":
    main()

5. 简单文件加密和解密

编写一个简单的Python脚本来加密和解密文本文件。

from Crypto.Cipher import AES
from Crypto.Util.Padding import pad, unpad
from Crypto.Random import get_random_bytes
import base64

def encrypt_file(file_path, key):
    cipher = AES.new(key, AES.MODE_CBC)
    ct_bytes = cipher.encrypt(pad(open(file_path, "rb").read(), AES.block_size))
    iv = base64.b64encode(cipher.iv).decode('utf-8')
    ct = base64.b64encode(ct_bytes).decode('utf-8')
    with open(file_path + ".enc", "w") as f:
        f.write(f"{iv}:{ct}")

def decrypt_file(file_path, key):
    with open(file_path, "r") as f:
        iv, ct = f.read().split(':')
    iv = base64.b64decode(iv)
    ct = base64.b64decode(ct)
    cipher = AES.new(key, AES.MODE_CBC, iv)
    pt = unpad(cipher.decrypt(ct), AES.block_size)
    with open(file_path.replace(".enc", ""), "wb") as f:
        f.write(pt)

key = get_random_bytes(16)  # Use a secure method to generate a key in a real-world scenario
file_path = input("Enter file path: ")
choice = input("Encrypt (e) or Decrypt (d)? ").lower()

if choice == 'e':
    encrypt_file(file_path, key)
elif choice == 'd':
    decrypt_file(file_path, key)
else:
    print("Invalid choice")