类型约束技巧使用typing模块强化类型提示避免运行时类型错误。例如为函数参数和返回值添加明确的类型注解from typing import List, Dict, Optional def process_data(data: List[Dict[str, int]]) - Optional[float]: if not data: return None return sum(item[value] for item in data) / len(data)对可能为None的值使用Optional类型提示结合isinstance进行运行时检查from typing import Optional def safe_divide(a: float, b: Optional[float]) - float: if b is None or b 0: raise ValueError(Divisor cannot be None or zero) return a / b异常处理基础捕获特定异常而非泛化的Exception避免隐藏潜在问题try: result some_risky_operation() except (ValueError, IndexError) as e: logging.error(fSpecific error occurred: {e}) raise CustomError(Operation failed) from e为自定义异常创建清晰的继承结构class DataValidationError(Exception): Base class for data validation errors pass class InvalidFormatError(DataValidationError): Raised when data format is invalid pass上下文管理器使用contextlib处理资源管理确保资源释放from contextlib import contextmanager contextmanager def managed_resource(path): resource acquire_resource(path) try: yield resource finally: release_resource(resource)参数验证结合pydantic进行复杂数据验证from pydantic import BaseModel, validator class InputModel(BaseModel): user_id: int values: list[float] validator(user_id) def validate_user_id(cls, v): if v 0: raise ValueError(User ID must be positive) return v异步代码处理为异步代码添加类型约束和异常处理from typing import Awaitable async def fetch_data(url: str) - Awaitable[dict]: try: async with aiohttp.ClientSession() as session: response await session.get(url) return await response.json() except aiohttp.ClientError as e: raise DataFetchError(fFailed to fetch {url}) from e边界条件检查对输入参数进行前置验证def calculate_percentage(value: float, total: float) - float: if not isinstance(value, (int, float)): raise TypeError(Value must be numeric) if total 0: raise ValueError(Total must be positive) return (value / total) * 100返回值处理处理可能的多类型返回值from typing import Union def parse_input(input: str) - Union[int, float, str]: try: return int(input) except ValueError: try: return float(input) except ValueError: return input.strip()日志记录结合异常处理进行详细日志记录import logging logger logging.getLogger(__name__) def critical_operation(): try: perform_operation() except Exception as e: logger.exception(Critical operation failed) notify_admins(fFailure: {str(e)}) raise测试辅助为测试添加类型约束的mock对象from unittest.mock import MagicMock from typing import Any def create_mock_response(status: int, data: Any) - MagicMock: mock MagicMock() mock.status_code status mock.json.return_value data return mock
