Exception 參數

1. 要取得異常發生之參數，可使用以下語法：

   try:
   	You do your operations here;
   	......................
   # 舊語法
   except ExceptionType, Argument:
   # 新語法
   except ExceptionType as Argument:
   	You can print value of Argument here...
   

2. 範例：列印異常屬性 IOError 的編號，參數變數設為 e。

   pyuser@deyu:~/zzz$ cat try5.py 
   #!/usr/bin/python
   import sys
   
   try:
       fo = open(sys.argv[1], "r")
       data = fo.read()
   except IOError as e:
       print("Error: can\'t read file", sys.argv[1])
       print("Error number =", e.errno)
   else:
       wordlist = data.split()
       print("Word count for", sys.argv[1], "=", len(wordlist))
       fo.close()
   finally:
       print("程式結束")
   

3. 執行結果：IOError 的錯誤碼為 2。

   pyuser@deyu:~/zzz$ ./try5.py /etc/qwe
   Error: can't read file /etc/qwe
   Error number = 2
   程式結束