Python中异常处理：10大常见异常及其处理实例

原创悠悠 2025-02-24 12:30 2阅读 0赞

在Python编程中，异常处理是一种机制，用于在程序执行过程中遇到错误时进行适当的处理。以下是Python中10种常见的异常以及相应的处理实例：

1. **ZeroDivisionError**：当除数为零时引发。示例：
   ```python
   try:
       division = 1 / 0
   except ZeroDivisionError as e:
       print(f"Error: {e}. Avoid dividing by zero.")
   ```

2. **TypeError**：当操作或函数应用于不合适的类型时引发。示例：
   ```python
   try:
       int_string = "32"
       float_number = int_string + ".5"
       print(float_number)
   except TypeError as e:
       print(f"Error: {e}. Type conversion may be required.")
   ```

3. **ValueError**：当数据不符合预期格式时引发。示例：
   ```python
   try:
       email = "invalid-email"
       validate_email(email)
   except ValueError as e:
       print(f"Error: {e}. Email validation failed.")
   ```

4. **KeyError**：当试图访问字典中不存在的键时引发。示例：
   ```python
   try:
       my_dict = {"name": "Alice", "age": 25}
       print(my_dict["address"]))
   except KeyError as e:
       print(f"Error: {e}. Key 'address' not found in dictionary.")
   ```

5. **IndexError**：当尝试访问列表中的某个索引超出范围时引发。示例：
   ```python
   try:
       my_list = [1, 2, 3]
       print(my_list[4])
   except IndexError as e:
       print(f"Error: {e}. Index '4' is out of range for list.")
   ```

6. **FileNotFoundError**：当尝试打开一个不存在的文件时引发。示例：
   ```python
   try:
       file_to_open = "nonexistent_file.txt"
       with open(file_to_open, 'r') as f:
           print(f.read())
   except FileNotFoundError as e:
       print(f"Error: {e}. File 'nonexistent_file.txt' not found.")
   ```

7. **IOError**：这是`FileNotFoundError`的父类，当文件操作遇到更广泛的错误时引发。示例：
   ```python
   try:
       file_to_open = "broken_file"
       with open(file_to_open, 'r') as f:
           print(f.read())
   except IOError as e:
       print(f"Error: {e}. File 'broken_file' could not be opened due to an error.")
   ```

8. **SystemExit**：在Python中，当调用`os.system()`或`sys.exit()`时会引发。示例：
   ```python
   try:
       exit_message = "Program gracefully stopped."
       os.system("echo " + exit_message)
       sys.exit(0)  # Normal exit, no error code
   except SystemExit as e:
       print(f"Error: {e}. Program was terminated via 'sys.exit()'.")
   ```

9. **Timeout**：当使用`time.sleep()`或其他可能导致阻塞的操作时，可能会遇到超时问题。示例：
   ```python
   try:
       time_to_wait = 5  # seconds
       sleep(time_to_wait)
       print("Action completed within the timeout.")
   except TimeoutError as e:
       print(f"Error: {e}. Action timed out after '{time_to_wait}' seconds.".format(time_to_wait)))
   ```

10. **SyntaxError**：当Python解析器遇到语法错误时，会引发此错误。示例：
    ```python
    try:
        invalid_code = "print('Hello, World!')\ninvalid_line"
        exec(invalid_code)  # Raises SyntaxError
       except SyntaxError as e:
           print(f"Error: {e}. Invalid syntax found in code.".format(invalid_code)))
   ```

以上就是Python中常见异常及其处理的示例。在实际编程中，根据具体需求和场景进行异常处理是非常重要的。