Hi, I would like to construct a transition matrix from a data frame with annual transitions of marked plants.
plant<-c(1:6) class<-c("seed","seed", "seed", "veg", "rep", "rep") fate<-c("dead", "veg","veg","rep", "rep", "veg") trans<-data.frame(plant, class, fate) plant class fate 1 1 seed dead 2 2 seed veg 3 3 seed veg 4 4 veg rep 5 5 rep rep 6 6 rep veg I have been using sql queries to do this, but I would like to construct the matrix in R since I plan to resample transitions using trans[sample(nrow(trans), 6, replace=T), ] I know I can get the original size vector using table() data.matrix(table(trans$class)) [,1] rep 2 seed 3 veg 1 but I don't know how to get counts of each class-fate combination where fate does NOT equal dead seed veg = 2 veg rep = 1 rep rep = 1 rep veg = 1 or how to divide the class-fate count by the original class count in the size vector to get survival probabilities seed veg = 2 / 3 seed = 0.67 veg rep = 1 / 1 veg = 1 rep rep = 1 / 2 rep = 0.5 rep veg = 1 / 2 rep = 0.5 or construct the square matrix with rows and columns in the same developmental sequence like dev<- c("seed","veg", "rep"). seed veg rep seed 0 0 0 veg 0.67 0 0.5 rep 0 1 0.5 Any help or suggestions would be appreciated. Thanks, Chris Stubben -- Los Alamos National Lab BioScience Division MS M888 Los Alamos, NM 87545 ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html