第 1 章：Python 环境搭建

// JavaScript: 获取用户列表并筛选成年人
const getAdults = (users) => {
  return users
    .filter(user => user.age >= 18)
    .map(user => ({
      name: user.name,
      age: user.age
    }));
};

const users = [
  { name: "Alice", age: 25 },
  { name: "Bob", age: 17 }
];
console.log(getAdults(users));

# Python: 获取用户列表并筛选成年人
def get_adults(users):
    return [
        {"name": user["name"], "age": user["age"]}
        for user in users
        if user["age"] >= 18
    ]

users = [
    {"name": "Alice", "age": 25},
    {"name": "Bob", "age": 17}
]
print(get_adults(users))

# 安装 requests 库（类似 axios，用于 HTTP 请求）
pip install requests

# 安装指定版本
pip install requests==2.31.0

# 导出当前环境的所有依赖
pip freeze > requirements.txt

# 从 requirements.txt 安装依赖（类似 npm install）
pip install -r requirements.txt

# 安装 uv（Windows）
powershell -c "irm https://astral.sh/uv/install.ps1 | iex"

# 安装 uv（macOS/Linux）
curl -LsSf https://astral.sh/uv/install.sh | sh

# 使用 uv 安装包（速度极快）
uv pip install requests

# 创建虚拟环境并激活（类似 npm 的 node_modules 隔离）
uv venv
source .venv/bin/activate  # macOS/Linux
.venv\Scripts\activate    # Windows

# 运行 Python 脚本（自动管理依赖）
uv run script.py

# 安装 miniconda（轻量版，推荐）
# 下载地址: https://docs.conda.io/en/latest/miniconda.html

# 创建隔离环境（类似 nvm 管理 Node 版本）
conda create -n myproject python=3.11

# 激活环境
conda activate myproject

# 安装包
conda install numpy pandas

# 退出环境
conda deactivate

Python: Select Interpreter
# 选择你安装的 Python 版本，如 Python 3.11.x

{
  "python.defaultInterpreterPath": "python",
  "editor.formatOnSave": true,
  "editor.defaultFormatter": "charliermarsh.ruff",
  "ruff.organizeImports": true,
  "python.analysis.typeCheckingMode": "basic",
  "python.analysis.autoImportCompletions": true,
  "files.exclude": {
    "**/__pycache__": true,
    "**/.venv": true,
    "**/*.pyc": true
  }
}

{
  "version": "0.2.0",
  "configurations": [
    {
      "name": "Python: 当前文件",
      "type": "debugpy",
      "request": "launch",
      "program": "${file}",
      "console": "integratedTerminal"
    }
  ]
}

# 使用 pip 安装
pip install jupyter

# 或使用 uv（更快）
uv pip install jupyter

jupyter notebook
# 自动打开浏览器，地址通常为 http://localhost:8888

$ python
Python 3.11.4 (main, Jun  7 2023, 10:13:09)
>>> print("Hello, World!")
Hello, World!
>>> name = "前端开发者"
>>> print(f"欢迎你，{name}！")
欢迎你，前端开发者！
>>> exit()  # 退出解释器

# hello.py
# 这是我的第一个 Python 程序

name = "前端开发者"
language = "Python"

print(f"Hello, {name}!")
print(f"欢迎来到 {language} 的世界！")

# 简单的计算
a = 10
b = 20
print(f"{a} + {b} = {a + b}")

$ python hello.py
Hello, 前端开发者!
欢迎来到 Python 的世界！
10 + 20 = 30

# macOS 安装（使用 Homebrew）
brew install pyenv

# Linux 安装
curl https://pyenv.run | bash

# Windows 安装（使用 pyenv-win）
# 通过 PowerShell 安装：
Invoke-WebRequest -UseBasicParsing -Uri "https://raw.githubusercontent.com/pyenv-win/pyenv-win/master/pyenv-win/install-pyenv-win.ps1" -OutFile "./install-pyenv-win.ps1"; &"./install-pyenv-win.ps1"

# 常用工作流示例
# 1. 安装 Python 3.12
pyenv install 3.12.0

# 2. 在项目中指定 Python 版本（类似 .nvmrc）
cd my-project
pyenv local 3.12.0
# 这会创建 .python-version 文件

# 3. 查看当前使用的版本
pyenv version
# 输出: 3.12.0 (set by /path/to/my-project/.python-version)

# macOS 安装
brew install pipx
pipx ensurepath

# Linux 安装
sudo apt install pipx
pipx ensurepath

# Windows 安装
pip install pipx
# 然后用 pipx 安装其他工具

# 安装常用开发工具
pipx install ruff       # 代码检查和格式化
pipx install black      # 代码格式化
pipx install poetry     # 包管理器
pipx install httpie     # 类似 curl 但更友好

# 查看已安装
pipx list

$ python -c "import this"
The Zen of Python, by Tim Peters

Beautiful is better than ugly.        # 优美胜于丑陋
Explicit is better than implicit.      # 明了胜于晦涩
Simple is better than complex.         # 简单胜于复杂
Complex is better than complicated.    # 复杂胜于凌乱
Flat is better than nested.            # 扁平胜于嵌套
Sparse is better than dense.           # 间隔胜于紧凑
Readability counts.                    # 可读性很重要
Special cases aren't special enough to break the rules.
Although practicality beats purity.    # 但实用性打败纯粹性
Errors should never pass silently.
Unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one-- and preferably only one --obvious way to do it.
Although that way may not be obvious at first unless you're Dutch.
Now is better than never.
Although never is often better than *right* now.
If the implementation is hard to explain, it's a bad idea.
If the implementation is easy to explain, it may be a good idea.
Namespaces are one honking great idea -- let's do more of those!