[R] pipe

[Prof Brian D Ripley]

On Sun, 24 Mar 2002 ggrothendieck at yifan.net wrote:

>     [this msg was first bounced and the manually approved;
>      don't capitalize "xxx": it looks too much like a word
>      used in a particular kind of spam.   Your list maintainer, MM]
>
>
> I would like to read in a .csv file ignoring all lines
> before the header line.  I am counting on the header
> line being the first line that has xxx in it.   I don't
> know how many lines to skip prior to that line, otherwise
> I would use the skip= feature of read.csv.
>
> This is sort of what I would like to do, although I gather
> this is not real R since I tried it without success:
>
> my.table <- read.csv("gawk '/xxx/{++z};z' myfile.csv |")
>
> The gawk program prints out only those lines starting from
> the first line containing xxx.
>
> I have played around with pipe() but could not get anything
> to work.
>
> I am using R 1.4.1 on Windows 2000.
>
> Any ideas on how to accomplish this?

Windows has very limited support for pipes on GUI executables.  A
version with pipe should work under Rterm.

However, one could use R to read the file with a line at a time with
readLines, check each line until you get the header, then pass the
connection to read.csv. If the header is to be read by read.csv, push it
back.

-- 
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 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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