On Tue, Feb 08, 2011 at 08:27:38PM +0530, pankaj borah wrote: > Hi, > > I have two lists > > 1) List1- 30,000 rows and 104 columns > > 2) List2- a list of 14000 selected rownames? from List 1 > > Now, I want to extract all the 104 columns of List1? matching with the 14000 > selected rownames from List2.? > > Psedocode will be something like this: > match rownames(List2) with rownames(List1) > extract selected matched 104 coloumns from (List1) > strore in-> List3 > > So the resulting List3 will contain 14,000 rows and 104 coloumns. > > How do I do it in R ?
Hi. Let me use a small example df <- data.frame(a=1:7, b=11:17, row.names=letters[1:7]) df a b a 1 11 b 2 12 c 3 13 d 4 14 e 5 15 f 6 16 g 7 17 Is the following what you are asking for in terms of this small example? df[c("b", "c", "g"), ] a b b 2 12 c 3 13 g 7 17 Petr Savicky. ______________________________________________ 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.