On Tue, Nov 15, 2011 at 11:23 AM, Joshua Wiley <jwiley.ps...@gmail.com> wrote: > Hi, > > Look at ?"[" > > anadata <- newdata[, cmn] > ## i.e., extract all rows (the first argument is empty of the 2 column > anadata <- newdata[, 2]
Or, if this is part of a more general problem and the column names are not necessarily in sequence: > newdata <- data.frame(V1=1:3, V2=4:6, V3=7:9) > newdata[, paste("V", 2, sep="")] [1] 4 5 6 Sarah > Hope this helps, > > Josh > > On Tue, Nov 15, 2011 at 8:02 AM, haohao Tsing <haohaor...@gmail.com> wrote: >> hi R,users >> Now I read a data from a txt file >> newdata<-read.table("1.txt") >> in the 1.txt ,there are several column shown as below >> 1 3 4 5 >> 2 3 5 6 >> 4 5 6 7 >> so when I want analysis the second column >> anadata<-newdata$V2 >> >> but my question I can not use some certain variable to indice the column? >> e.g >> cmn=2 >> anadata<-newdata$Vcmn >> >> how can I finish this command ?can anyone help me ? thank yo . -- Sarah Goslee http://www.functionaldiversity.org ______________________________________________ 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.