[R] request: How to get column name

[Petr PIKAL]

r-help-bounces at r-project.org napsal dne 03.09.2008 15:54:08:

> try this:
> 
> x <- c(3,3,3,3,0,0,0,0,5,5,5,5,8,8,8,8)
> x <- matrix(x, nrow=4)
> 
> which(colSums(x == 0) == nrow(x))

Isn't this the same?

which(colSums(x)==0)

Regards
Petr

> 
> I hope it helps.
> 
> Best,
> Dimitris
> 
> 
> Muhammad Azam wrote:
> > Dear R community
> > I have a problem regarding which of the column in a matrix contains 
all of 
> zero elements. e.g.
> > x=c(3,3,3,3,0,0,0,0,5,5,5,5,8,8,8,8); x=matrix(x, nrow=4)
> > the output is
> > 
> >> x
> >> 
> >      [,1] [,2] [,3] [,4]
> > [1,]    3    0    5    8
> > [2,]    3    0    5    8
> > [3,]    3    0    5    8
> > [4,]    3    0    5    8
> > In this case the required column is second so the result should be 
"2". How 
> can i get it? 
> >
> > 
> > best regards
> >
> > Muhammad Azam 
> >
> >
> >
> > 
> >    [[alternative HTML version deleted]]
> >
> > ______________________________________________
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> > PLEASE do read the posting guide 
http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
> >
> > 
> 
> 
> -- 
> Dimitris Rizopoulos
> Assistant Professor
> Department of Biostatistics
> Erasmus University Medical Center
> 
> Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
> Tel: +31/(0)10/7043399
> Fax: +31/(0)10/7044657
> 
> ______________________________________________
> R-help at 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
> and provide commented, minimal, self-contained, reproducible code.