Hi Nymphita, ?upper.tri
x <- as.data.frame(matrix(1:6,6,6)) x[upper.tri(x,diag=TRUE)] <- 0 x Cheers, Tsjerk On Wed, Feb 15, 2012 at 4:33 PM, nymphita <nymph...@gmail.com> wrote: > Hello! > > I'm trying to build a lower triangular matrix (with zeros in the diagonal) > from a particular dataframe. > > The matrix I have to construct has 203 rows and 203 columns and that makes > 20503 values to be included within (that's why I can't do it manually). > > To illustrate the dataframe I have, I'll give you an example of a dataframe > and matrix with dimensions 6x6 (to make it shorter!) > > My dataframe looks more or less like this (but longeeeer): > (i= number of row, j=number of column, k=value to be included in the matrix) > > http://r.789695.n4.nabble.com/file/n4390813/df.png > > An the matrix I should look like this: > > http://r.789695.n4.nabble.com/file/n4390813/matrix.png > > Can anyone help me about how to do it? > > I'm a new R user, and I've tried several combinations of diag(), > lower.tri(), matrix(), etc. without any luck... and I don't know if I'm > unaware of a command that can work this out. > > > > -- > View this message in context: > http://r.789695.n4.nabble.com/built-a-lower-triangular-matrix-from-dataframe-tp4390813p4390813.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > 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. -- Tsjerk A. Wassenaar, Ph.D. post-doctoral researcher Molecular Dynamics Group * Groningen Institute for Biomolecular Research and Biotechnology * Zernike Institute for Advanced Materials University of Groningen The Netherlands ______________________________________________ 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.
