xreadlines() being used with file.tell() and file.seek()

[midtoad]

maybe you could re-post your code with standard indenting of 4 or 8
characters.   I have trouble telling where I am with the single-character
indenting you are using. 

but, a few questions:

Do you need to read in the entire file, or just certain lines?
Do you always know the pattern in advance? i.e. will it always be every 5th
line?  If so, you may not need two loops.  

If you want to read every line but only split out every nth line, you could
use integer div operator so that when you get to line no. count / n = 0,
you print .

cheers
Stewart