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。

   [dywang@dywmac zzz]$ cat except5.py 
   #!/usr/bin/python
   # coding: utf-8
   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。

   [dywang@dywmac zzz]$ ./except5.py /etc/qwe
   Error: can't read file /etc/qwe
   Error number = 2
   程式結束