Python 20个必学实例盘点

news2024/10/25 18:44:05

Python

1. 计算器程序：

 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):       
   try:           
   return x / y       
   except ZeroDivisionError:           
   print("除数不能为零")

   print("选择操作：")   
   print("1.加法")   
   print("2.减法")   
   print("3.乘法")   
   print("4.除法")

   choice = input("输入操作序号(1/2/3/4): ")

   num1 = float(input("输入第一个数字: "))   
   num2 = float(input("输入第二个数字: "))

   if choice == '1':       
   print(num1, "+", num2, "=", add(num1, num2))   
   elif choice == '2':       
   print(num1, "-", num2, "=", subtract(num1, num2))   
   elif choice == '3':       
   print(num1, "*", num2, "=", multiply(num1, num2))   
   elif choice == '4':       
   print(num1, "/", num2, "=", divide(num1, num2))   
   else:       
   print("输入错误")

2. 列表去重：

    def unique_elements(input_list):       
    return list(set(input_list))

   my_list = [1, 2, 2, 3, 4, 4, 5]   
   print("原始列表:", my_list)   
   print("去重后的列表:", unique_elements(my_list))

3. 文件内容复制：


def copy_file(source_path, destination_path):       
with open(source_path, 'r') as source:           
with open(destination_path, 'w') as destination:               
for line in source:                   
destination.write(line)

source_file = 'source.txt'   
destination_file = 'destination.txt'   
copy_file(source_file, destination_file)   
print("文件复制完成。")

4. 字符串反转：

def reverse_string(input_string):
return input_string[::-1]
print("反转前的字符串:", "Hello World")
print("反转后的字符串:", reverse_string("Hello World"))

5. 生成随机密码：


import random
import string
def generate_password(length):
characters = string.ascii_letters + string.digits + string.punctuation
password = ''.join(random.choice(characters) for i in range(length))
return password
password_length = 10   
print("生成的密码:", generate_password(password_length))

6. 简单的网页爬虫：

import requests
from bs4 import BeautifulSoup
def simple_web_crawler(url):
response = requests.get(url)
soup = BeautifulSoup(response.text, 'html.parser')
return soup.get_text()
website = 'https://www.example.com'
print("网站内容:", simple_web_crawler(website))

7. 排序列表：

def sort_list(input_list):
  return sorted(input_list)
  my_list = [3, 1, 4, 1, 5, 9, 2, 6, 5]
  print("未排序的列表:", my_list)
  print("排序后的列表:", sort_list(my_list))

8. 计算字符频率：


 from collections import Counter
 def character_frequency(input_string):
 return Counter(input_string)
 my_string = "hello world"
 print("字符频率:", character_frequency(my_string))

9. 生成斐波那契数列：


def fibonacci(n):
a, b = 0, 1
result = []
for _ in range(n):
result.append(a)
a, b = b, a + b       
return result
print("斐波那契数列前10个数:", fibonacci(10))

10. 简单的待办事项应用：

class Todo:
def __init__(self):           
self.tasks = []
def add_task(self, task):
self.tasks.append(task)
def remove_task(self, task):
self.tasks.remove(task)
def display_tasks(self):
for index, task in enumerate(self.tasks):
print(f"{index}. {task}")
my_todo = Todo()
my_todo.add_task("Learn Python")
my_todo.add_task("Read a book")
my_todo.display_tasks()
my_todo.remove_task("Read a book")
my_todo.display_tasks()

11. 文本分析 - 计算单词数量：

def count_words(text):
words = text.split()
return len(words)
text = "This is a simple text for word counting."
print("单词数量:", count_words(text))

12. 数据可视化 - 使用Matplotlib绘制简单折线图：


import matplotlib.pyplot as plt
def plot_line_graph(x_values, y_values, title, x_label, y_label):
plt.plot(x_values, y_values)
plt.title(title)
plt.xlabel(x_label)
plt.ylabel(y_label)
plt.show()
x_values = [1, 2, 3, 4]
y_values = [10, 40, 50, 20]
plot_line_graph(x_values, y_values, "Simple Line Graph", "X-axis", "Y-axis")

13. 自动化脚本 - 重命名文件：


import os
def rename_files(directory, new_name):
for filename in os.listdir(directory):           
old_file = os.path.join(directory, filename)           
new_file = os.path.join(directory, new_name + os.path.splitext(filename)[1])
os.rename(old_file, new_file)
rename_files('/path/to/directory', 'new_filename')

14. 网络应用 - 检查网站是否可用：


import requests
def check_website_status(url):
try:
response = requests.get(url)           
if response.status_code == 200:              
return True           
else:               
return False
except requests.exceptions.RequestException:
return False
website = 'https://www.example.com'
print("网站是否可用:", check_website_status(website))

15. 日期和时间 - 格式化当前日期：

from datetime import datetime
def format_current_date(format_string='%Y-%m-%d'):
return datetime.now().strftime(format_string)
print("当前日期:", format_current_date())

16. 文件处理 - 读取CSV文件内容：


import csv
def read_csv_file(file_path):
with open(file_path, newline='') as csvfile:
reader = csv.reader(csvfile)
data = [row for row in reader]
return datacsv_file = 'example.csv'
data = read_csv_file(csv_file)
print(data)

17. 正则表达式 - 验证电子邮件地址：

import re
def validate_email(email):
pattern = r'^[\w\.-]+@[\w\.-]+\.\w+$'
return re.match(pattern, email) is not None
email = "example@example.com"
print("电子邮件地址有效:", validate_email(email))

18. 数据加密 - 使用MD5加密字符串：


import hashlib
def encrypt_string(text):
return hashlib.md5(text.encode()).hexdigest()
encrypted_text = encrypt_string("Hello World!")
print("加密后的字符串:", encrypted_text)

19. 数据筛选 - 筛选列表中的偶数：


def filter_even_numbers(numbers):
return [num for num in numbers if num % 2 == 0]
numbers = [1, 2, 3, 4, 5, 6]
even_numbers = filter_even_numbers(numbers)
print("偶数列表:", even_numbers)

20. 进程管理 - 运行外部命令：


import subprocess
 def run_command(command):
 try:
 result = subprocess.check_output(command, shell=True)
 return result.decode('utf-8').strip()
 except subprocess.CalledProcessError as e:
 return e.output.decode('utf-8').strip()
 command = "ls -l"
 print("命令输出:", run_command(command))