Many thanks to all for resolving my issue!

On Thu, Aug 27, 2009 at 10:33 PM, Martin Maechler <
maechler@stat.math.ethz.ch> wrote:

> >>>>> "MO" == Moshe Olshansky <m_olshansky@yahoo.com>
> >>>>>     on Wed, 26 Aug 2009 23:36:22 -0700 (PDT) writes:
>
>    MO> You can do
>    MO> for (i in 1:ncol(x)) {names <-
> rownames(x)[which(x[,i]==1)];eval(parse(text=paste("V",i,".ind<-names",sep="")));}
>
> you can, but after   install.packages("fortunes")
>
>  > require("fortunes")
>  > fortune("parse")
>
>  If the answer is parse() you should usually rethink the question.
>     -- Thomas Lumley
>        R-help (February 2005)
>
>
> So please use one of the other answers given in the thread...
>
>
>    MO> --- On Thu, 27/8/09, Steven Kang <stochastickang@gmail.com> wrote:
>
>    >> From: Steven Kang <stochastickang@gmail.com>
>    >> Subject: [R] Help on efficiency/vectorization
>    >> To: r-help@r-project.org
>    >> Received: Thursday, 27 August, 2009, 4:13 PM
>    >> Dear R users,
>    >>
>    >> I am trying to extract the rownames of a data set for which
>    >> each columns
>    >> meet a certain criteria. (condition - elements of each
>    >> column to be equal
>    >> 1)
>    >>
>    >> I have the correct result, however I am seeking for more
>    >> efficient (desire
>    >> vectorization) way in implementing such problem as it can
>    >> get quite messy if
>    >> there are hundreds of columns.
>    >>
>    >> Arbitrary data set and codes are shown below for your
>    >> reference:
>    >>
>    >> x <- as.data.frame(matrix(round(runif(50),0),nrow=5))
>    >>
>    >> rownames(x) <- letters[1:dim(x)[1]]
>    >>
>    >> > x
>    >>   V1 V2 V3 V4 V5 V6 V7 V8 V9 V10
>    >> a  0  1   1
>    >> 1   0   0
>    >> 0   0   1    0
>    >> b  1  1   1
>    >> 1   0   1
>    >> 0   0   1    1
>    >> c  0  1   1
>    >> 0   0   0
>    >> 0   0   0    1
>    >> d  1  0   0
>    >> 1   1   1
>    >> 1   1   0    0
>    >> e  1  0   0
>    >> 0   0   1
>    >> 1   0   1    0
>    >>
>    >> V1.ind <- rownames(x)[x[,"V1"]==1]
>    >> V2.ind <- rownames(x)[x[,"V2"]==1]
>    >> V3.ind <- rownames(x)[x[,"V3"]==1]
>    >> V4.ind <- rownames(x)[x[,"V4"]==1]
>    >> :
>    >> :
>    >> V10.ind <- rownames(x)[x[,"V10"]==1]
>    >>
>    >> > V1.ind
>    >> [1] "b" "d" "e"
>    >> > V2.ind
>    >> [1] "a" "b" "c"
>    >> > V3.ind
>    >> [1] "a" "b" "c"
>    >> :
>    >> :
>    >> > V10.ind
>    >> [1] "b" "c"
>    >>
>    >>
>    >>
>    >> Your expertise in resolving this issue would be highly
>    >> appreciated.
>    >>
>    >>
>    >> Steve
>    >>
>    >>     [[alternative HTML version deleted]]
>    >>
>    >> ______________________________________________
>    >> R-help@r-project.org
>    >> mailing list
>    >> https://stat.ethz.ch/mailman/listinfo/r-help
>    >> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html<http://www.r-project.org/posting-guide.html>
>    >> and provide commented, minimal, self-contained,
>    >> reproducible code.
>    >>
>
>    MO> ______________________________________________
>    MO> R-help@r-project.org mailing list
>    MO> https://stat.ethz.ch/mailman/listinfo/r-help
>    MO> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html<http://www.r-project.org/posting-guide.html>
>    MO> and provide commented, minimal, self-contained, reproducible code.
>

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