search for: 7800x1

...to make a subset of the data using the logical vector R1(length 1024) so that only the cases where R1 is TRUE are included. I can do this by: R1data<-alldata[R1] that gives a vector 7800 long (there are 300 TRUE's in R1) so I do R1data<-as.data.frame(alldata[R1]) which gives a matrix 7800x1 so I write: R1data<-alldata[R1];dim(R1data)<-c(300,26) which gives the data in the right form except I haven't inherited the names at all. (a) How to do that? (b) Is there a convenient one-liner (or more) where I can just write something like the first expression (which is intuit...