[BangPypers] How to handle files efficiently in python

[Vishal]

On Wed, Mar 23, 2011 at 11:57 AM, Senthil Kumaran <orsenthil at gmail.com>wrote:

> On Wed, Mar 23, 2011 at 2:24 PM, Senthil Kumaran <orsenthil at gmail.com>
> wrote:
> > - file IO based. Seek to end of file and do a seek in the reverse
> >  direction based on a factor matching the size, and process and
> >  display. ( I found a good discussing on StackOverflow after writing
> >  this).
>
>
> http://stackoverflow.com/questions/136168/get-last-n-lines-of-a-file-with-python-similar-to-tail
>
> --
> Senthil
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if you could read the entire file in one go...(i.e. unless your file is more
than 50MB)...how about the following?

# n is the number of lines you want to read.
l = open(filename).read().rsplit('\n', n+1)
# following is to keep the memory requirement low.
# but this is optional, if you only want to print the lines, and then end
the python process.
l[0] = None
gc.collect()
print '\n'.join(l[1:])
... do other stuff

if you cannot read the entire file in one go...then the stackoverflow answer
above from S.Lott is best.

Enjoy,
Vishal

-- 
Thanks and best regards,
Vishal Sapre

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