简单的编程代码

[wangweihanNB]

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🐍 Python 篇

1. 批量重命名文件

import os

# 把当前文件夹下所有 .txt 文件改为 .md
for filename in os.listdir('.'):
    if filename.endswith('.txt'):
        new_name = filename.replace('.txt', '.md')
        os.rename(filename, new_name)
        print(f'已重命名: {filename} → {new_name}')

2. 简易计算器

def calculator(a, b, op):
    if op == '+': return a + b
    if op == '-': return a - b
    if op == '*': return a * b
    if op == '/': return a / b if b != 0 else '除数不能为0'

print(calculator(10, 5, '+'))  # 15
print(calculator(10, 5, '/'))  # 2.0

3. 爬取网页标题

import requests
from bs4 import BeautifulSoup

url = 'https://example.com'
response = requests.get(url)
soup = BeautifulSoup(response.text, 'html.parser')
print(f'网页标题: {soup.title.string}')

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🌐 JavaScript 篇

4. 深拷贝对象

function deepClone(obj) {
    return JSON.parse(JSON.stringify(obj));
}

const original = { name: 'Alice', hobbies: ['reading', 'coding'] };
const cloned = deepClone(original);
cloned.hobbies.push('gaming');

console.log(original.hobbies); // ['reading', 'coding']（原对象不受影响）

5. 防抖函数（优化搜索输入）

function debounce(func, delay) {
    let timer;
    return function(...args) {
        clearTimeout(timer);
        timer = setTimeout(() => func.apply(this, args), delay);
    };
}

// 用法：输入停止500ms后才执行
const search = debounce((keyword) => {
    console.log('搜索:', keyword);
}, 500);

6. 数组去重（三种写法）

const arr = [1, 2, 2, 3, 4, 4, 5];

// 方法1：Set
const unique1 = [...new Set(arr)];

// 方法2：filter
const unique2 = arr.filter((item, index) => arr.indexOf(item) === index);

// 方法3：reduce
const unique3 = arr.reduce((acc, cur) => {
    return acc.includes(cur) ? acc : [...acc, cur];
}, []);

console.log(unique1); // [1, 2, 3, 4, 5]

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☕ Java 篇

7. 读取文件内容

import java.nio.file.*;
import java.io.IOException;

public class FileReader {
    public static void main(String[] args) {
        try {
            String content = Files.readString(Path.of("example.txt"));
            System.out.println(content);
        } catch (IOException e) {
            System.out.println("文件读取失败: " + e.getMessage());
        }
    }
}

8. Lambda 排序

import java.util.*;

public class SortExample {
    public static void main(String[] args) {
        List<String> names = Arrays.asList("Alice", "Bob", "Charlie");
        
        // 按长度排序
        names.sort((a, b) -> a.length() - b.length());
        System.out.println(names); // [Bob, Alice, Charlie]
        
        // 方法引用写法
        names.sort(Comparator.comparingInt(String::length));
    }
}

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