I was thinking of delegating stuff to IO.read when dealing with lines
On Thu, 12 May 2016 15:08:15 +0200
José Valim <jose.va...@plataformatec.com.br> wrote:
> Not in your example but if you want to do it per line, then yes.
>
> On Thursday, May 12, 2016, Charles Okwuagwu <okwuagwu...@gmail.com>
> wrote:
>
> > def read(file, start, length) do
> > {ok, f} = :file.open(file, [:binary])
> > * {ok**, data} = :file.pread(f, start,** length)*
> > :file.close(f)
> > dataend
> >
> > We are not reading the whole file, or are we? *:file.pread/3*
> >
> >
> > On Thursday, May 12, 2016 at 1:36:05 PM UTC+1, José Valim wrote:
> >>
> >> We need to consider that performance wise they are quite
> >> different. We can move the cursor when reading lines, we can't
> >> move the cursor when reading bytes. We would actually need to load
> >> the file into Elixir. It would probably be more interesting to add
> >> a File.position instead of hiding the underlying behaviour.
> >>
> >>
> >> *José Valim*
> >> www.plataformatec.com.br
> >> Skype: jv.ptec
> >> Founder and Director of R&D
> >>
> >> On Thu, May 12, 2016 at 2:25 PM, eksperimental
> >> <eksper...@autistici.org> wrote:
> >>
> >>> Hi Charles,
> >>> thank you for your proposal.
> >>>
> >>> I think it could be an interesting addition. But rather than just
> >>> a convenience function, make it behave more like its IO
> >>> conterpart: IO.read/2
> >>>
> >>> Where you can pass the byte length, or :line.
> >>> Because sometimes is not about the bytes, but about the
> >>> information held in a certain number of lines in the file.
> >>>
> >>> I'm thinking something like
> >>>
> >>> File.read(file_path, :line, 1)
> >>>
> >>> # or to read the first five lines
> >>> File.read(file_path, :line, 1..5)
> >>>
> >>> I would like to know how the rest of the list feels about it.
> >>>
> >>>
> >>> On Mon, 9 May 2016 10:36:15 -0700 (PDT)
> >>> Charles Okwuagwu <okwua...@gmail.com> wrote:
> >>>
> >>> > Can we have this convenience as a function in the File module?
> >>> >
> >>> > read(file, start, length)
> >>> >
> >>> >
> >>> >
> >>> > http://stackoverflow.com/q/37121605/44080
> >>> >
> >>> > The suggested solution is not immideiately obvious
> >>> >
> >>> > {:ok, file} = :file.open(source_file, [:read, :binary])
> >>> >
> >>> > :file.position(file, 5) # start_position = 5
> >>> >
> >>> > :file.read(file, 10) # bytes to read = 10
> >>> >
> >>> >
> >>> >
> >>>
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> >>
>
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