Question on File Input and AST

[joy99]

Dear Group,

I have a file "test1.txt". Now, as I do the file handling, i try to do
any one of the following operations.

1. open_file=open("/python26/test1.txt","r") # FOR READING
2. open_file=open("/python26/test1.txt","r+") # FOR READING AND
WRITING BOTH
[Either of 1 or 2 to open as the need be]
3. read_file=open_file.read()
etc...

But how to work with "fileinput" or "ast".

I tried to read python docs and some backlog question answer in the
group but it did not help much.

If any one can kindly give one or two small examples. It would help me
much.

Best Regards,
Subhabrata.