[Head First Python]3. 文件与异常:处理错误

datafile.txt

Man: Is this the right room for an argument?
Other Man: I've told you once.
Man: No you haven't
Other Man:Yes I have
Man: When? and :
(pause)
Other Man: Just now.
Man: No you didn't!

sketch.py

 try:
     data = open ("datafile.txt")

     for each_line in data:
         try:
             (role, line_spoken) = each_line.split(":", 1)
             print(role, end = '')
             print(" said :", end = '')
             print(line_spoken, end = '')
         except ValueError:
             pass

     data.close()
 except IOError:
     print('this data file is missing!')

if语句取反用 not

if not each_line.find(':') == -1