Python异常处理（下）

三.实例

1. def boxPrint(symbol, width, height):
2. if len(symbol) != 1:
3. raise Exception('Symbol must be a single character string.')
4. if width <= 2:
5. raise Exception('Width must be greater than 2.')
6. if height <= 2:
7. raise Exception('Height must be greater than 2.')
8. print(symbol * width) #打印
9. for i in range(height - 2):
10. print(symbol + (' ' * (width - 2)) + symbol)
11. print(symbol * width)
12. for sym, w, h in (('*', 4, 4), ('O', 20, 5), ('x', 1, 3), ('ZZ', 3, 3)):
13. try:
14.         boxPrint(sym, w, h)
15. except Exception as err: #返回自定义错误
16. print('An exception happened: ' + str(err))