To create 6th column in the matrix m, you should use the cbind function. To calculate the vector of pairwise min or max values, you should use the pmin and pmax functions:
act.surv.time<-pmin(m[,"censoringTime"],m[,"survivalTime"]) m<-cbind(m,act.surv.time) raymond chiruka wrote: > > hie l would like to create a 6th column "actual surv time" from the > following data > > the condition being > if censoringTime>survivaltime then actual survtime =survival time > else actual survtime =censoring time > > the code l used to create the data is > > s=2 > while(s!=0){ n=20 > m<-matrix(nrow=n,ncol=4) > > colnames(m)=c("treatmentgrp","strata","censoringTime","survivalTime") > for(i in 1:20) > m[i,]<-c(sample(c(1,2),1,replace=TRUE),sample(c(1,2),1,replace=TRUE),rexp(1,.007),rexp(1,.002)) > m<-cbind(m,0) > m[m[,3]>m[,4],5]<-1 > colnames(m)[5]<-"censoring" > print(m) > s=s-1 > treatmentgrp strata censoringTime survivalTime censoring > [1,] 1 1 1.012159 1137.80922 0 > [2,] 2 2 32.971439 247.21786 0 > [3,] 2 1 85.758253 797.04949 0 > [4,] 1 1 16.999171 78.92309 0 > [5,] 2 1 272.909896 298.21483 0 > [6,] 1 2 138.230629 935.96765 0 > [7,] 2 2 91.529859 141.08405 0 > > > l keep getting an error message when i try to create the 6th column > > --------------------------------- > ______________________________________________ > 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 > and provide commented, minimal, self-contained, reproducible code. > -- View this message in context: http://www.nabble.com/creating-a-new-column-tf3704043.html#a10358728 Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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 and provide commented, minimal, self-contained, reproducible code.