JSON 快速入门

{  "name": "Arch Linux",  "version": "2024.01"}

["vim", "git", "docker"]

{  "name": "my-project",  "version": "1.0.0",  "dependencies": {    "react": "^18.2.0",    "next": "^14.0.0"  },  "scripts": {    "dev": "next dev",    "build": "next build",    "lint": "eslint ."  },  "keywords": ["react", "nextjs", "typescript"]}

// 正确{ "name": "Alice" }// 错误 - 单引号{ 'name': 'Alice' }// 错误 - 无引号{ name: "Alice" }

// 正确{ "status": "active" }// 错误{ "status": 'active' }

// 错误 - JSON 不支持注释{  "port": 3000  // 服务端口}// 如果需要注释，考虑使用 JSONC 格式（VS Code 的 tsconfig.json 等支持）// 或者把说明放在键名里{  "// port": "服务端口",  "port": 3000}

// 错误 - 最后一个元素后不能有逗号{  "a": 1,  "b": 2,}

// 错误{ "value": undefined }{ "value": NaN }

const text = '{"name": "Alice", "age": 30}';const data = JSON.parse(text);console.log(data.name); // Alice

const data = { name: "Alice", age: 30 };const text = JSON.stringify(data, null, 2);

const config = JSON.parse(raw);const port = config?.server?.port ?? 3000;

import json# 解析with open("config.json", "r", encoding="utf-8") as f:    data = json.load(f)# 生成with open("output.json", "w", encoding="utf-8") as f:    json.dump(data, f, indent=2, ensure_ascii=False)

对象      { "key": "value" }数组      ["a", "b", "c"]字符串    "hello"数字      42、3.14布尔      true / false空值      null嵌套      { "a": { "b": [1, 2] } }解析(JS)   JSON.parse(text)生成(JS)   JSON.stringify(obj)解析(PY)   json.load(f)生成(PY)   json.dump(obj, f)常见错误:  - 键名/字符串用单引号  - 有注释  - 尾逗号  - undefined / NaN