Dear all of you, I would like if someone can help me to know how I can read a matrix looking for positions in the matrix that are not null. I have a matrix with most of the "cells" or "positions" null, I am trying to know the invasion power of a plant (number 1 in the matrix when t==1). I would like to continue the model writing some condition when the value of the matrix in not null, but I don't know what function or loop I have to use to find the values > than 0 for the next step.
pop <- matrix(0,7,7)# Population matrix when t==0 pop[sample(1:length(pop),1)] <-1 #Population matrix when t==1 Thanks a lot, Judit [[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.