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]]
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)) 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]] > > ______________________________________________ > 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. > >-- 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
Dear Muhammad, Try also: 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) [1] 2 HTH, Jorge On Wed, Sep 3, 2008 at 9:45 AM, Muhammad Azam <mazam72@yahoo.com> 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]] > > ______________________________________________ > 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 > and provide commented, minimal, self-contained, reproducible code. >[[alternative HTML version deleted]]