Python Development

Python开发

Core Python language concepts, idioms, and best practices.

Python 核心语言概念、惯用写法与最佳实践。

Core Expertise

核心专业技能

Python Language: Modern Python 3.10+ features and idioms
Best Practices: Pythonic code, design patterns, SOLID principles
Debugging: Interactive debugging and profiling techniques
Performance: Optimization strategies and profiling
Async Programming: async/await patterns and asyncio

Python语言: 现代Python 3.10+版本特性与惯用写法
最佳实践: Pythonic代码、设计模式、SOLID原则
调试: 交互式调试与性能分析技术
性能: 优化策略与性能剖析
异步编程: async/await模式与asyncio

Modern Python Features (3.10+)

现代Python特性（3.10+）

Type Hints

类型提示

python

undefined

python

undefined

Modern syntax (Python 3.10+)

def process_items( items: list[str], # Not List[str] mapping: dict[str, int], # Not Dict[str, int] optional: str | None = None, # Not Optional[str] ) -> tuple[bool, str]: # Not Tuple[bool, str] """Process items with modern type hints.""" return True, "success"

Type aliases

type UserId = int type UserDict = dict[str, str | int]

def get_user(user_id: UserId) -> UserDict: return {"id": user_id, "name": "Alice"}

undefined

type UserId = int type UserDict = dict[str, str | int]

def get_user(user_id: UserId) -> UserDict: return {"id": user_id, "name": "Alice"}

undefined

Pattern Matching (3.10+)

模式匹配（3.10+）

python

def handle_command(command: dict) -> str:
    match command:
        case {"action": "create", "item": item}:
            return f"Creating {item}"
        case {"action": "delete", "item": item}:
            return f"Deleting {item}"
        case {"action": "list"}:
            return "Listing items"
        case _:
            return "Unknown command"

python

def handle_command(command: dict) -> str:
    match command:
        case {"action": "create", "item": item}:
            return f"Creating {item}"
        case {"action": "delete", "item": item}:
            return f"Deleting {item}"
        case {"action": "list"}:
            return "Listing items"
        case _:
            return "Unknown command"

Structural Pattern Matching

结构化模式匹配

python

def process_response(response):
    match response:
        case {"status": 200, "data": data}:
            return process_success(data)
        case {"status": 404}:
            raise NotFoundError()
        case {"status": code} if code >= 500:
            raise ServerError(code)

python

def process_response(response):
    match response:
        case {"status": 200, "data": data}:
            return process_success(data)
        case {"status": 404}:
            raise NotFoundError()
        case {"status": code} if code >= 500:
            raise ServerError(code)

Python Idioms

Python惯用写法

Context Managers

上下文管理器

python

undefined

python

undefined

File handling

with open("file.txt") as f: content = f.read()

Custom context manager

from contextlib import contextmanager

@contextmanager def database_connection(): conn = create_connection() try: yield conn finally: conn.close()

with database_connection() as conn: conn.execute("SELECT * FROM users")

undefined

from contextlib import contextmanager

@contextmanager def database_connection(): conn = create_connection() try: yield conn finally: conn.close()

with database_connection() as conn: conn.execute("SELECT * FROM users")

undefined

List Comprehensions

列表推导式

python

undefined

python

undefined

List comprehension

squares = [x**2 for x in range(10)]

Dict comprehension

word_lengths = {word: len(word) for word in ["hello", "world"]}

Set comprehension

unique_lengths = {len(word) for word in ["hello", "world", "hi"]}

Generator expression

sum_of_squares = sum(x**2 for x in range(1000000)) # Memory efficient

undefined

sum_of_squares = sum(x**2 for x in range(1000000)) # Memory efficient

undefined

Iterators and Generators

迭代器与生成器

python

def fibonacci():
    a, b = 0, 1
    while True:
        yield a
        a, b = b, a + b

python

def fibonacci():
    a, b = 0, 1
    while True:
        yield a
        a, b = b, a + b

Use generator

fib = fibonacci() first_ten = [next(fib) for _ in range(10)]

Generator expression

even_squares = (x**2 for x in range(10) if x % 2 == 0)

undefined

even_squares = (x**2 for x in range(10) if x % 2 == 0)

undefined

Debugging

调试

Interactive Debugging

交互式调试

python

import pdb

def problematic_function():
    value = calculate()
    pdb.set_trace()  # Debugger breakpoint
    return process(value)

bash

undefined

python

import pdb

def problematic_function():
    value = calculate()
    pdb.set_trace()  # Debugger breakpoint
    return process(value)

bash

undefined

Debug on error

python -m pdb script.py

pytest with debugger

uv run pytest --pdb # Drop into pdb on failure uv run pytest --pdb --pdbcls=IPython.terminal.debugger:TerminalPdb

undefined

uv run pytest --pdb # Drop into pdb on failure uv run pytest --pdb --pdbcls=IPython.terminal.debugger:TerminalPdb

undefined

Performance Profiling

性能分析

bash

undefined

bash

undefined

CPU profiling

uv run python -m cProfile -s cumtime script.py | head -20

Line-by-line profiling (temporary dependency)

uv run --with line-profiler kernprof -l -v script.py

Memory profiling (temporary dependency)

uv run --with memory-profiler python -m memory_profiler script.py

Real-time profiling (ephemeral tool)

uvx py-spy top -- python script.py

Quick profiling with scalene

uv run --with scalene python -m scalene script.py

undefined

uv run --with scalene python -m scalene script.py

undefined

Built-in Debugging Tools

内置调试工具

python

undefined

python

undefined

Trace execution

import sys

def trace_calls(frame, event, arg): if event == 'call': print(f"Calling {frame.f_code.co_name}") return trace_calls

sys.settrace(trace_calls)

import sys

def trace_calls(frame, event, arg): if event == 'call': print(f"Calling {frame.f_code.co_name}") return trace_calls

sys.settrace(trace_calls)

Memory tracking

import tracemalloc

tracemalloc.start()

import tracemalloc

tracemalloc.start()

... code to profile

snapshot = tracemalloc.take_snapshot() top_stats = snapshot.statistics('lineno') for stat in top_stats[:10]: print(stat)

undefined

snapshot = tracemalloc.take_snapshot() top_stats = snapshot.statistics('lineno') for stat in top_stats[:10]: print(stat)

undefined

Async Programming

异步编程

Basic async/await

基础async/await

python

import asyncio

async def fetch_data(url: str) -> dict:
    async with httpx.AsyncClient() as client:
        response = await client.get(url)
        return response.json()

async def main():
    result = await fetch_data("https://api.example.com")
    print(result)

asyncio.run(main())

python

import asyncio

async def fetch_data(url: str) -> dict:
    async with httpx.AsyncClient() as client:
        response = await client.get(url)
        return response.json()

async def main():
    result = await fetch_data("https://api.example.com")
    print(result)

asyncio.run(main())

Concurrent Tasks

并发任务

python

async def process_multiple():
    # Run concurrently
    results = await asyncio.gather(
        fetch_data("url1"),
        fetch_data("url2"),
        fetch_data("url3"),
    )
    return results

python

async def process_multiple():
    # Run concurrently
    results = await asyncio.gather(
        fetch_data("url1"),
        fetch_data("url2"),
        fetch_data("url3"),
    )
    return results

With timeout

async def with_timeout(): try: result = await asyncio.wait_for(fetch_data("url"), timeout=5.0) except asyncio.TimeoutError: print("Request timed out")

undefined

async def with_timeout(): try: result = await asyncio.wait_for(fetch_data("url"), timeout=5.0) except asyncio.TimeoutError: print("Request timed out")

undefined

Design Patterns

设计模式

Dependency Injection

依赖注入

python

from typing import Protocol

class Database(Protocol):
    def query(self, sql: str) -> list: ...

def get_users(db: Database) -> list:
    return db.query("SELECT * FROM users")

python

from typing import Protocol

class Database(Protocol):
    def query(self, sql: str) -> list: ...

def get_users(db: Database) -> list:
    return db.query("SELECT * FROM users")

Factory Pattern

工厂模式

python

def create_handler(handler_type: str):
    match handler_type:
        case "json":
            return JSONHandler()
        case "xml":
            return XMLHandler()
        case _:
            raise ValueError(f"Unknown handler: {handler_type}")

python

def create_handler(handler_type: str):
    match handler_type:
        case "json":
            return JSONHandler()
        case "xml":
            return XMLHandler()
        case _:
            raise ValueError(f"Unknown handler: {handler_type}")

Decorator Pattern

装饰器模式

python

from functools import wraps
import time

def timer(func):
    @wraps(func)
    def wrapper(*args, **kwargs):
        start = time.time()
        result = func(*args, **kwargs)
        end = time.time()
        print(f"{func.__name__} took {end - start:.2f}s")
        return result
    return wrapper

@timer
def slow_function():
    time.sleep(1)

python

from functools import wraps
import time

def timer(func):
    @wraps(func)
    def wrapper(*args, **kwargs):
        start = time.time()
        result = func(*args, **kwargs)
        end = time.time()
        print(f"{func.__name__} took {end - start:.2f}s")
        return result
    return wrapper

@timer
def slow_function():
    time.sleep(1)

Best Practices

最佳实践

SOLID Principles

SOLID原则

Single Responsibility:

python

undefined

单一职责原则:

python

undefined

Bad: Class does too much

class User: def save(self): pass def send_email(self): pass def generate_report(self): pass

Good: Separate concerns

class User: def save(self): pass

class EmailService: def send_email(self, user): pass

class ReportGenerator: def generate(self, user): pass

undefined

class User: def save(self): pass

class EmailService: def send_email(self, user): pass

class ReportGenerator: def generate(self, user): pass

undefined

Fail Fast

快速失败

python

def process_data(data: dict) -> str:
    # Validate early
    if not data:
        raise ValueError("Data cannot be empty")
    if "required_field" not in data:
        raise KeyError("Missing required field")

    # Process with confidence
    return data["required_field"].upper()

python

def process_data(data: dict) -> str:
    # Validate early
    if not data:
        raise ValueError("Data cannot be empty")
    if "required_field" not in data:
        raise KeyError("Missing required field")

    # Process with confidence
    return data["required_field"].upper()

Functional Approach

函数式编程方法

python

undefined

python

undefined

Prefer immutable transformations

def process_items(items: list[int]) -> list[int]: return [item * 2 for item in items] # New list

Over mutations

def process_items_bad(items: list[int]) -> None: for i in range(len(items)): items[i] *= 2 # Mutates input

undefined

def process_items_bad(items: list[int]) -> None: for i in range(len(items)): items[i] *= 2 # Mutates input

undefined

Project Structure (src layout)

项目结构（src布局）

my-project/
├── pyproject.toml
├── README.md
├── src/
│   └── my_project/
│       ├── __init__.py
│       ├── core.py
│       ├── utils.py
│       └── models.py
└── tests/
    ├── conftest.py
    ├── test_core.py
    └── test_utils.py

my-project/
├── pyproject.toml
├── README.md
├── src/
│   └── my_project/
│       ├── __init__.py
│       ├── core.py
│       ├── utils.py
│       └── models.py
└── tests/
    ├── conftest.py
    ├── test_core.py
    └── test_utils.py

另请参阅

uv-run - Running scripts, temporary dependencies, PEP 723
uv-project-management - Project setup and dependency management
uv-tool-management - Installing CLI tools globally
python-testing - Testing with pytest
python-code-quality - Linting and type checking with ruff/ty
python-packaging - Building and publishing packages
uv-python-versions - Managing Python interpreters

uv-run - 运行脚本、临时依赖管理、PEP 723
uv-project-management - 项目配置与依赖管理
uv-tool-management - 全局安装CLI工具
python-testing - 使用pytest进行测试
python-code-quality - 使用ruff/ty进行代码检查与类型校验
python-packaging - 构建与发布包
uv-python-versions - 管理Python解释器

References

参考资料

Python docs: https://docs.python.org/3/
Type hints: https://docs.python.org/3/library/typing.html
Async: https://docs.python.org/3/library/asyncio.html
Detailed guide: See REFERENCE.md

Python官方文档: https://docs.python.org/3/
类型提示文档: https://docs.python.org/3/library/typing.html
异步编程文档: https://docs.python.org/3/library/asyncio.html
详细指南: 参考REFERENCE.md

python-development

Original

Translation

Python Development

Python开发

Core Expertise

核心专业技能

Modern Python Features (3.10+)

现代Python特性（3.10+）

Type Hints

类型提示

Modern syntax (Python 3.10+)

Modern syntax (Python 3.10+)

Type aliases

Type aliases

Pattern Matching (3.10+)

模式匹配（3.10+）

Structural Pattern Matching

结构化模式匹配

Python Idioms

Python惯用写法

Context Managers

上下文管理器

File handling

File handling

Custom context manager

Custom context manager

List Comprehensions

列表推导式

List comprehension

List comprehension

Dict comprehension

Dict comprehension

Set comprehension

Set comprehension

Generator expression

Generator expression

Iterators and Generators

迭代器与生成器

Use generator

Use generator

Generator expression

Generator expression

Debugging

调试

Interactive Debugging

交互式调试

Debug on error

Debug on error

pytest with debugger

pytest with debugger

Performance Profiling

性能分析

CPU profiling

CPU profiling

Line-by-line profiling (temporary dependency)

Line-by-line profiling (temporary dependency)

Memory profiling (temporary dependency)

Memory profiling (temporary dependency)

Real-time profiling (ephemeral tool)

Real-time profiling (ephemeral tool)

Quick profiling with scalene

Quick profiling with scalene

Built-in Debugging Tools

内置调试工具

Trace execution

Trace execution

Memory tracking

Memory tracking

... code to profile

... code to profile

Async Programming

异步编程

Basic async/await

基础async/await

Concurrent Tasks

并发任务

With timeout

With timeout

Design Patterns