Reason, I need to do this in awk and not R:

Let's say 'x' is the tabular representation of a sparse contingency table
> x
   x10 x11 x12 x13 x14 x15 x16 x17 x18 x19 Freq
1    0   0   0   2   2   2   0   2   0   2   54
5    1   0   0   2   2   2   0   2   1   2    1
6    1   0   1   0   2   2   0   2   0   2  137
7    1   0   1   1   2   1   0   1   0   1   14
10   1   0   1   1   2   2   0   2   1   2  110


I need to generate that dataset from which such a contingency table could be
made. That dataset would have sum(x$Freq) = 316 rows. Note that this is only
a sample example. Real examples that I could be dealing with would have up
to 50 variables and tens of thousands of cases. I can definitely make a
dataset in R itself by replicating the first row 54 times, the third row 137
times and so on (for a real example, each replication could be a 1000
times), but I bet this is going to be as inefficient way of doing things as
it could be.

However, if I write 'x' to file and then call the awk script above, I get my
dataset within fraction of seconds (including the time to write and read
files on the OS).

Any suggestions now on how to get the 'pipe' command work?

Thanks






On Tue, Apr 8, 2008 at 4:45 AM, Jan T. Kim <jtk@cmp.uea.ac.uk> wrote:

> On Mon, Apr 07, 2008 at 07:42:50PM -0500, born.to.b.wyld@gmail.com wrote:
> > Can anyone point out why this is not working?
> >
> > y<-read.table(pipe('  awk '{ n = $1; sub( ".*" $1 " " ,"") ; while ( n--
> )
>                            ^
> > print }'  temp.txt '))
>          ^
>
> one problem is that your single-quoted R string contains single quotes
> which I've pointed to with "^" above. You probably intend these single
> quotes to be part of the awk command line, but R can\'t know that unless
> you escape them...  ;-)
>
> In the future, can you please describe explicitly how it "is not working",
> and also give a bit more context, such as a few lines of description of
> the content of temp.txt, and why you're trying to use awk (rather than R
> itself) to achieve whatever you're trying to achieve?
>
> Best regards, Jan
> --
>  +- Jan T. Kim -------------------------------------------------------+
>  |             email: jtk@cmp.uea.ac.uk                               |
>  |             WWW:   http://www.cmp.uea.ac.uk/people/jtk             |
>  *-----=<  hierarchical systems are for files, not for humans  >=-----*
>
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