python3.4读写.txt文件出错，而。py文件正常？

>>> f=open("D:\\python34\2.txt",'w')
Traceback (most recent call last):
  File "<pyshell#19>", line 1, in <module>
    f=open("D:\\python34\2.txt",'w')
OSError: [Errno 22] Invalid argument: 'D:\\python34\x02.txt'
>>> f=open("D:\\python34\safdsf.py",'w')