beginner's questions - manipulating text files

[Cédric Lucantis]

Le Wednesday 02 July 2008 01:16:30 Ben Keshet, vous avez écrit :
> Hi,
>
> I am a very beginner Python programmer with limited programming
> experience overall.
>
> I am trying to write a script that will search for the second and third
> appearance of the symbol '@' in a file, will read a random line between
> them, and write the line into a new file. So far I was only able to open
> the file using 'open', but I am not sure how to proceed. I tried to read
> it line by line using 'readline' but was not sure how to manipulate the
> text the way I need to.
>

If the file you're reading is not too big, you can use file.readlines() which 
read all the files and returns its content as a list of lines.

> Could anyone please give me |a basic guidance as for what functions may
> be useful for my purpose? (e.g how to search for a string '@' in a text?
> how to identify its location?

text.find('@') will return the position of the first occurence of '@', or a 
negative value if not found.

> how to choose a random number in a defined 
> range?

random.randrange(start, stop)

> how to read that line number from a text file? etc.)| 

if you read the file with readlines(), just lines[lineno]

you'll find more infos in the following sections:

http://docs.python.org/lib/bltin-file-objects.html
http://docs.python.org/lib/string-methods.html
http://docs.python.org/lib/module-random.html

-- 
Cédric Lucantis