looping over a big file

[martian]

Hi,

I've a couple of questions regarding the processing of a big text file
(16MB).

1) how does python handle:

> for line in big_file:

is big_file all read into memory or one line is read at a time or a buffer
is used or ...?

2) is it possible to advance lines within the loop? The following doesn't
work:

> for line in big_file:
         line_after  = big_file.readline()

the function readline (file pointer) is "out of sync" with the loop (and
this suggests bug_file is not read one line at a time in the loop).

Thanks,
Fernando Martins