Python exception handling skills are revealed to help you become a programming master

1. try...except...finally

   This is the most commonly used exception handling structure in python, which is used to catch exceptions and execute corresponding processing logic. The try block contains the code to be executed, the except block contains the handling logic after catching the exception, and the finally block contains the code that will be executed regardless of whether an exception occurs. For example:

try:
# 执行代码
except Exception as e:
# 捕获异常并处理
finally:
# 无论是否发生异常都会执行的代码

2. raise

   The

   raise statement is used to throw exceptions, and you can specify the exception type and exception information to be thrown. For example:

raise ValueError("无效的参数值")

3. assert

   The assert statement is used to check whether a certain condition is true. If it is not true, an AssertionError exception is thrown. For example:

assert x > 0, "x must be greater than 0"

4. Custom exception

   You can create your own exception class, which inherits from the Exception class. For example:

class MyError(Exception):
pass

raise MyError("我的错误")

5. Use the logging module to record exceptions

   The logging module can be used to record exception information. For example:

import logging

try:
# 执行代码
except Exception as e:
logging.error("发生异常", exc_info=True)

6. Use context manager to handle exceptions

   The context manager is a mechanism used to simplify exception handling. For example:

with open("file.txt", "r") as f:
# 执行代码

If an exception occurs in the with block, file f will be automatically closed.

7. Use exceptions to control program flow

   Exceptions can also be used to control program flow. For example, you can use exceptions to implement loops or branches. For example:

while True:
try:
# 执行代码
except KeyboardInterrupt:
break

8. Use exceptions for unit testing

   Exceptions can also be used for unit testing. For example, you can use exceptions to check whether a function throws the correct exception. For example:

import unittest

class MyTestCase(unittest.TestCase):

def test_my_function(self):
with self.assertRaises(ValueError):
my_function(-1)

The above tips can help you handle exceptions better and improve the robustness of your code.

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