> sapply(seq(4,ncol(dat)), function(i) > survdiff(Surv(time,completion=="2")~dat[,i], data=dat, > subset=group=="3")$chisq) [1] 0.0944 4.4854 3.4990
Chris -----Original Message----- From: Charles Determan Jr [mailto:deter...@umn.edu] Sent: Thursday, October 18, 2012 3:04 PM To: r-help@r-project.org Subject: [R] looping survdiff? Hello, I am trying to set up a loop that can run the survdiff function with the ultimate goal to generate a csv file with the p-values reported. However, whenever I try a loop I get an error such as "invalid type (list) for variable 'survival_data_variables[i]". This is a subset of my data: structure(list(time = c(1.51666666666667, 72, 72, 25.7833333333333, 72, 72, 72, 72, 72, 72, 1.18333333333333, 0.883333333333333, 1.15, 0.866666666666667, 72, 1.03333333333333, 72, 1.05, 72, 22.7666666666667), group = c(2L, 1L, 3L, 3L, 3L, 4L, 4L, 1L, 3L, 3L, 3L, 3L, 4L, 3L, 3L, 4L, 3L, 4L, 3L, 4L), completion = structure(c(2L, 1L, 1L, 2L, 1L, 1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 1L, 2L, 1L, 2L, 1L, 2L), .Label = c("1", "2"), class = "factor"), var1 = structure(c(2L, 2L, 3L, 1L, 1L, 3L, 1L, 1L, 1L, 3L, 2L, 2L, 4L, 3L, 2L, 4L, 2L, 4L, 2L, 4L), .Label = c("1", "2", "3", "4"), class = "factor"), var2 = structure(c(3L, 3L, 1L, 1L, 2L, 4L, 3L, 3L, 2L, 4L, 2L, 1L, 2L, 1L, 2L, 2L, 4L, 4L, 2L, 3L), .Label = c("1", "2", "3", "4"), class = "factor"), var3 = structure(c(4L, 2L, 3L, 1L, 3L, 4L, 4L, 2L, 2L, 4L, 2L, 2L, 1L, 2L, 2L, 2L, 1L, 3L, 4L, 1L), .Label = c("1", "2", "3", "4"), class = "factor")), .Names = c("time", "group", "completion", "var1", "var2", "var3"), row.names = c(NA, 20L), class = "data.frame") The loop I have been trying for just group 3 is: d=data.frame() for(i in 4:6){ a=assign(paste("p-value",i,sep=""), survdiff(Surv(time, completion=="2")~dat[i], data=dat[group=="3",], rho=0)) b=as.matrix(a$chisq) d=rbind(d, b) write.csv(d, file="C:/.../junk.csv", quote=FALSE)} Perhaps I am making this more difficult than it needs to be. Thanks for any help, Charles [[alternative HTML version deleted]] ********************************************************** Electronic Mail is not secure, may not be read every day, and should not be used for urgent or sensitive issues ______________________________________________ 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.
