Python Exception Handling: A Complete Guide

The exception handling mechanism in Python allows for catching and handling exceptions during program execution to prevent crashes or unexpected outcomes. Here are common uses of exception handling in Python:

1. try-except statement: Use a try block to contain code that may throw an exception, and if an exception occurs, enter the corresponding except block for handling. The syntax is as follows:

try:
    # 可能抛出异常的代码
except ExceptionType:
    # 异常处理代码

1. Multiple except statements: You can add multiple except blocks after the try block, with each block handling a different type of exception. You can catch specific types of exceptions or use the general Exception to catch all exceptions. Syntax as follows:

try:
    # 可能抛出异常的代码
except ExceptionType1:
    # 异常1处理代码
except ExceptionType2:
    # 异常2处理代码
except ExceptionType3:
    # 异常3处理代码
except:
    # 其他异常处理代码

1. Else statement: It can be added after a try-except statement to handle the logic when no exception occurs. The code inside the else block will only be executed if no exception is raised. The syntax is as follows:

try:
    # 可能抛出异常的代码
except ExceptionType:
    # 异常处理代码
else:
    # 没有异常时的处理代码

1. The finally statement: It can be added after a try-except statement, and the code inside the finally block will be executed regardless of whether an exception occurs. It is usually used for releasing resources. The syntax is as follows:

try:
    # 可能抛出异常的代码
except ExceptionType:
    # 异常处理代码
finally:
    # 无论是否发生异常都会执行的代码

1. Throwing Exceptions: You can use the raise statement to actively throw exceptions, in order to interrupt program execution in unexpected circumstances. The syntax is as follows:

raise ExceptionType("异常信息")

By properly utilizing exception handling mechanisms, it is possible to improve the robustness and reliability of a program, ensuring it can correctly handle various unexpected situations during runtime.