tail

[Chris Angelico]

On Sun, 24 Apr 2022 at 21:11, Antoon Pardon <antoon.pardon at vub.be> wrote:
>
>
>
> Op 23/04/2022 om 20:57 schreef Chris Angelico:
> > On Sun, 24 Apr 2022 at 04:37, Marco Sulla<Marco.Sulla.Python at gmail.com>  wrote:
> >> What about introducing a method for text streams that reads the lines
> >> from the bottom? Java has also a ReversedLinesFileReader with Apache
> >> Commons IO.
> >
> > 1) Read the entire file and decode bytes to text
> > 2) Split into lines
> > 3) Iterate backwards over the lines
> >
> > Tada! Done. And in Python, quite easy. The downside, of course, is
> > that you have to store the entire file in memory.
>
> Why not just do:
>
> tail = collections.deque(text_stream, maxlen = nr_of_lines)
> tail.reverse()
> ...
>

You still need to read the entire file, and you also restrict the max
line count, so you can't iterate this to take the next block of lines.

ChrisA