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

[Prof Brian Ripley]

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 ...

> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

PLEASE do as we ask.


-- 
Brian D. Ripley,                  ripley at 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