Python Basic Programming Syntax — Tutorials & Examples

A comprehensive, beginner-friendly collection of Python notes and runnable scripts. Topics include core syntax, OOP, exceptions, files & OS, modules/packages, web scraping, and mini Pygame projects. Each example is small, focused, and easy to run from the command line.

Why This Repository

• Practical, hands-on learning with minimal boilerplate
• Organized by topic for quick lookup and reference
• Examples are self-contained and demonstrate one concept at a time
• Suitable for self-study, coursework, and interview warm‑ups

Folder Structure

基本编程语法学习笔记/
├─ 单例设计/                 # design patterns: singleton via __new__
├─ 封装系统项目集/           # simple encapsulation exercises & projects
├─ 异常/                     # try/except, raise, propagation
├─ 文件的基本操作/           # file I/O, copy, read/write, os utilities
├─ 模块/                     # imports, packages, aliases, setup
│  └─ hm_message/            # tiny example package (send/receive)
├─ 爬虫/                     # requests, BeautifulSoup, regex, CSV outputs
│  ├─ 学习案例/              # small learning demos
│  └─ 实战正式项目/          # full scraping scripts with data
├─ pygame项目实战/           # step-by-step Pygame demos & mini games
├─ test/ test1/              # small sandboxes for experiments
└─ resources/screenshots/    # put screenshots used in README here

Detailed Contents

单例设计 (Singleton via __new__)

• __new__方法重写.py: Demonstrates overriding __new__ to ensure only one instance is created. Explains lifecycle differences between __new__ and __init__, object identity (id()), and typical pitfalls such as multiple inheritance.
• Use cases: configuration managers, connection pools, and loggers.

封装系统项目集 (Encapsulation Exercises)

• 士兵开枪封装案例.py: Encapsulates Soldier and Gun interactions; methods like fire(), ammo management, and responsibility boundaries between objects.
• 名片管理系统: cards_main.py, cards_tools.py: CLI CRUD demo with functions for add/search/update/delete, file persistence patterns to extend, and simple input validation.
• 房子家具增添系统: 家具类与房屋类的组合关系、面积占用、可用空间检测与异常处理建议。

异常 (Exceptions)

• 完整的异常语法.py: Full try/except/else/finally flow; where to place cleanup.
• 异常的传递.py: Shows stack propagation and where exceptions surface.
• 异常的简单捕获.py, 捕获错误类型.py: Catching broad vs specific exceptions; trade-offs.
• 抛出异常.py: Raising custom exceptions with helpful messages.

文件的基本操作 (Files & OS)

• Read/Write: 读取文件.py, 写入文件.py, line-by-line 分行读取文件.py for memory efficiency.
• Copying: 复制小文件.py vs 复制大文件.py (buffered reads and chunk sizes).
• Utilities: os模块.py for path ops, listing, and existence checks.
• eval计算器.py: Parsing simple arithmetic safely; caveats and safer alternatives (ast.literal_eval).
• Notes: Readme and Readme[复件] contain quick tips.

模块 (Modules & Packages)

• Import styles: 导入模块.py, from_import 导入.py, aliases 导入模块指定别名.py.
• Package example hm_message/: send_message.py, receive_message.py, __init__.py layout and relative imports.
• setup.py: Minimal packaging primer; how Python finds modules; PYTHONPATH basics.
• Name guard demos: _name_测试导入.py, _name_测试模块.py illustrate if __name__ == "__main__": usage.

爬虫 (Web Scraping)

• 学习案例:
  • requests爬虫.py: Basic GET requests, headers, response handling.
  • Beautiful soup 爬虫.py: Parsing HTML with bs4, element selection.
  • 正则表达式*.py: Extracting structured data via regex; pros/cons vs DOM parsers.
  • JSON conversions: json转换为python.py, 把python转变为json.py, sample text.json.
• 实战正式项目:
  • 豆瓣高分电影排行榜*.py: Fetch and write douban_movies.csv with columns like title, rating, url.
  • 番茄小说采集: 番茄小说数据爬取*.py, fanqie_*.csv outputs; pagination and category selection.
  • 当当网爬取数据.py: Example of multi-page scraping and deduplication strategies.
  • 爬取网页所有图片.py: Download images; file naming, collision handling, and retry policies.
  • 疫情采集信息项目.py: Data extraction into CSV/JSON; rate-limit and error handling notes.
  • Ethics & legality: obey robots.txt, add delays, and do not overload servers.

类的继承_派生 (OOP: Inheritance & Polymorphism)

• 单继承.py, 多继承.py: Linear vs diamond inheritance; method resolution order (MRO).
• 覆盖父类方法.py, 拓展父类方法.py: Overriding and calling super() correctly.
• 多态案例.py: Interface-based programming; behavior substitution.
• Attributes/methods: 类属性.py, 类方法.py, 静态方法.py differences and use cases.
• Privacy: 父类的私有属性及方法.py, 私有属性与方法.py show name mangling and access patterns.

pygame项目实战 (Pygame Demos)

• 1.pygame入门.py → 9.事件监听.py: Progressive steps from window creation, drawing backgrounds and sprites, Rect usage, to game loop and event handling.
• 大鱼吃小鱼.py: A small playable demo; movement, collision detection, scoring, and simple state management.
• 测试模块.py: Quick checks and sandboxes for Pygame utilities.
• Images under pygame项目实战/images/ used by demos.

Tests & Sandboxes

• test/, test1/ subfolders provide scratch space for experimenting with code snippets and quick validations.

Setup

• Requirements: Python 3.8+
• Optional dependencies for specific folders are listed in requirements.txt:
  • requests and beautifulsoup4 for web scraping
  • pygame for Pygame demos

Install all optional dependencies at once:

pip install -r requirements.txt

How to Run Examples

1. Navigate to the folder of the example.
2. Run the script in cmd:

python 路径\到\示例.py

3. For scraping scripts in 爬虫/实战正式项目/, make sure you have network access and note that outputs like CSV files will be created next to the script.
4. For pygame项目实战/, ensure pygame is installed and a windowed environment is available.
5. For package demos under 模块/hm_message/, run a module or import functions:

python 模块\_name_测试模块.py
python -c "from 模块.hm_message.send_message import send; send()"

Running Tips

• Prefer virtual environments for isolating dependencies.
• On Windows, enable UTF‑8 in cmd if you see encoding issues:

chcp 65001

• Use python -m pip install ... if pip is not on PATH.

Highlights by Topic

• OOP & Patterns: inheritance, polymorphism, overriding, singleton via __new__
• Exceptions: error types, simple/advanced catching, raising, propagation
• Files & OS: safe read/write, copying large files, os utilities, eval demo
• Modules & Packages: absolute/relative imports, aliases, simple package layout
• Web Scraping: requests, BeautifulSoup, regex parsing, data export to CSV
• Pygame: window setup, drawing, events, game loop, small playable demos

Example Outputs

• Scraping: CSV files like douban_movies.csv, fanqie_*.csv with headers; logs printed on progress and failures.
• Files: Copies created in destination folders; large file copies use chunked reads.
• Pygame: Window renders sprites and detects collisions; close with Esc or window button.

FAQ

• Q: Why are there many small scripts?
  • A: Each script focuses on one concept to reduce cognitive load.
• Q: Do I need all dependencies?
  • A: No. Install only what's needed per folder, or use requirements.txt to install all.
• Q: Can I use this for teaching?
  • A: Yes. The examples are designed for classroom demos and assignments.

Maintainers Notes

• This repository is actively curated for teaching and self‑study.
• Examples are intentionally small and focused; feel free to extend.

Contributing

• Fork the repository and create a feature branch.
• Keep examples small and focused; match folder/topic organization.
• Add a short docstring and minimal comments to explain intent.
• Provide sample inputs/outputs when relevant (CSV, JSON, screenshots).

License

MIT