Python异常处理：try/except的多种使用场景

原创 ╰+哭是因爲堅強的太久メ 2025-02-17 07:54 5阅读 0赞

在Python编程中，异常处理是通过try/except语句来实现的。这用于捕获和处理可能在程序执行过程中出现的问题。以下列举了try/except的一些常见使用场景：

1. 文件操作：
   ```python
   try:
       file = open("myfile.txt", "r")
       contents = file.read()
       file.close()  # 关闭文件以释放资源
   except FileNotFoundError:
       print("File not found.")
   ```

2. 网络请求：
   ```python
   import requests

response = try_response():
       response = requests.get('https://example.com')
       return response.text
   except (requests.exceptions.RequestException, ConnectionError)):
       print("An error occurred while making a request to the internet.")
       return None

if response is not None:
       process_data(response)
   ```

3. 业务逻辑错误：
   ```python
   def calculate_total(order_items):
       total = 0
       try:
           for item in order_items:
               price = float(item['price'])
               quantity = int(item['quantity'])
               total += price * quantity
       except ValueError as ve:
           print(f"Value error occurred: {ve}. Skipping this item.")
       return total

# 假设order_items是一个列表，每个元素代表一个订单项目
   order_total = calculate_total(order_items)
   ```

4. 自定义异常处理：
   ```python
   class CustomException(Exception):
       def __init__(self, message):
           self.message = message
           super().__init__(message)

try:
       raise CustomException("This is a custom error.")
   except CustomException as ce:
       print(ce.message)
   ```

以上就是Python中try/except语句的多种使用场景。在实际编程过程中，根据具体情况灵活运用异常处理机制。