Re: [R] need to find (and distinguish types of) carriage returns in a file that is scanned using scan

From: Prof Brian Ripley <ripley_at_stats.ox.ac.uk>
Date: Sun 20 Aug 2006 - 01:16:00 EST

On Sat, 19 Aug 2006, Quicke, Donald L J wrote:

> Hope this is not too trivial
> I am reading a large file using scan.

Why scan?

> In one part of this file there is a chunk of text within which i need to
> know the positions of line breaks. But scan seems only

only what?

> An example of the file is:
> "
> a 0 1 0
> bftt 020
> cftt T 1 R
>
> a 0 1 2 1 2
> b 0 1 2 2 2
> c 0 10 00
> "
>
> so precisely i need in the scanned file in R to know where each carriage
> return is in the file so that i can then identify the text strings (i.e.
> a, bftt, cftt, a, b, c ) that immediately follow the carriage return

Sounds like a job for readLines.

> On a subsidiary matter, it would be very helpful if i could distinguish
> between Unix, Dos, and Mac carriage returns in the data file

AFAIK there is only type of carriage return character (ASCII code Ctrl-M). If you mean between CRLF, LF and perhaps CR line endings, you need to read the files as raw bytes since R's text mode regards all three as equally a line ending. But that can perfectly well be done using binary-mode connections.

>
> thanks
>
> i should note also, that the input file contains much other stuff and is
> not in the form of a table that can be read using read.table or other
> read version. Nor do i know beforehand how many elements there are in
> each line

Sounds like a job for connections ...

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>
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PLEASE do as we ask.

-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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Received on Sun Aug 20 01:22:15 2006

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