异常处理和调试：Python的try-catch长什么样？

基础异常处理

try:
    result = 10 / 0
except ZeroDivisionError as e:
    print(f"除零错误: {e}")
except (TypeError, ValueError) as e:
    print(f"类型或值错误: {e}")
except Exception as e:
    print(f"其他错误: {e}")
else:
    print("没有异常时执行")
finally:
    print("总是执行")

区别： Python用except不用catch，可以用元组捕获多种异常，还有else块。

自定义异常

class InsufficientBalanceError(Exception):
    def __init__(self, balance, amount):
        self.balance = balance
        self.amount = amount
        super().__init__(f"余额不足: 当前{balance}元, 取出{amount}元")
class BankAccount:
    def init(self, balance):
        self.balance = balance
  
    def withdraw(self, amount):
        if amount > self.balance:
            raise InsufficientBalanceError(self.balance, amount)
        self.balance -= amount
        return self.balance
account = BankAccount(100)
try:
    account.withdraw(200)
except InsufficientBalanceError as e:
    print(e)  # 余额不足: 当前100元, 取出200元

上下文管理器（with语句）

with open("data.txt", "r") as f:
    content = f.read()
自动关闭文件
自定义上下文管理器
from contextlib import contextmanager
@contextmanager
def database_connection(url):
    print(f"连接到 {url}")
    conn = "模拟连接"
    try:
        yield conn
    finally:
        print("关闭连接")
with database_connection("mysql://localhost/db") as conn:
    print(f"使用 {conn}")

pdb调试器

def complex_function(data):
    result = []
    for item in data:
        processed = item.strip().lower()
        breakpoint()  # Python 3.7+ 自动启动pdb
        if processed:
            result.append(processed)
    return result

常用命令： n(下一步), s(进入函数), c(继续), p var(打印变量), q(退出)

logging模块

import logging
logging.basicConfig(
    level=logging.DEBUG,
    format='%(asctime)s - %(levelname)s - %(message)s',
    handlers=[
        logging.FileHandler('app.log'),
        logging.StreamHandler()
    ]
)
logger = logging.getLogger(name)
logger.info("一般信息")
logger.error("错误")
try:
    1 / 0
except Exception as e:
    logger.exception("除零错误")  # 自动记录堆栈

最佳实践

# 不要吞掉异常
try:
    do_something()
except Exception:
    pass  # BAD!
应该记录并处理
try:
    do_something()
except Exception as e:
    logger.error(f"处理失败: {e}")
    raise  # 或做恢复操作

总结

本系列持续更新中，关注不迷路。