Python怎样处理异常_Python异常处理技巧总结

try...except

try:
    # 可能会出错的代码
    # 例如：读取文件、网络请求、类型转换等
    result = 10 / 0  # 这会引发 ZeroDivisionError
except ZeroDivisionError:
    # 如果发生 ZeroDivisionError 错误，执行这里的代码
    print("除数不能为零！")
except FileNotFoundError:
    # 如果发生 FileNotFoundError 错误，执行这里的代码
    print("文件不存在！")
except Exception as e:
    # 捕获所有其他类型的异常，并打印错误信息
    print(f"发生了未知错误：{e}")
else:
    # 如果 try 块中的代码没有发生任何异常，执行这里的代码
    print("一切正常！")
finally:
    # 无论是否发生异常，最终都会执行这里的代码
    print("程序执行完毕！")

try

try

except

except

except

except

else

try

finally

class MyCustomError(Exception):
    def __init__(self, message):
        super().__init__(message)
        self.message = message

    def __str__(self):
        return f"MyCustomError: {self.message}"

try:
    raise MyCustomError("这是一个自定义错误！")
except MyCustomError as e:
    print(e)

try...except

try...except

try...except

try...except

except

logging

import logging

logging.basicConfig(filename='error.log', level=logging.ERROR)

try:
    result = 10 / 0
except ZeroDivisionError as e:
    logging.error(f"除数为零错误：{e}")
    print("除数不能为零！")

ZeroDivisionError

error.log

assert

assert

assert

AssertionError

def divide(a, b):
    assert b != 0, "除数不能为零！"
    return a / b

try:
    result = divide(10, 0)
    print(result)
except AssertionError as e:
    print(e)

assert

assert

-O

assert

try...finally

file = None
try:
    file = open("my_file.txt", "r")
    # 读取文件内容
    content = file.read()
    print(content)
finally:
    if file:
        file.close()

with

with open("my_file.txt", "r") as file:
    # 读取文件内容
    content = file.read()
    print(content)
# 文件会自动关闭

with

__enter__

__exit__

__exit__