Python Exception

1 異常的處理

#!/usr/bin/python3

# exceptions.py by Bill Weinman [http://bw.org/]
# This is an exercise file from Python 3 Essential Training on lynda.com
# Copyright 2010 The BearHeart Gorup, LLC


def main():
    try:
       fh = open('sslines.txt')  #當文件不存在時
    except IOError as e:
        print("Could not open the file.come back tommorow",e)
    else:
         for line in fh: print(line.strip())

if __name__ == "__main__": main()

2 拋出異常

#!/usr/bin/python3
# exceptions.py by Bill Weinman [http://bw.org/]
# This is an exercise file from Python 3 Essential Training on lynda.com
# Copyright 2010 The BearHeart Gorup, LLC


def main():
    try:    
        for line in readFile("han.doc"):
            print(line.strip())
    except IOError: print('file does not exist')
    
    except ValueError as e:print(e)
    
def  readFile(filename):
     if filename.endswith('.txt'):
         fh=open(filename)
         return fh.readlines()
     else:
          raise ValueError('File name must end with .txt')
    


if __name__ == "__main__": main()