Hi all, I have data that looks like number|grouping I would like to preform stats for each grouping so 1|5 6|5 10|5 11|5 3|9 5|9 10|9 Say I would like to take the median for above, I should be returned 2 lines, one for group #5 and one for group #9 Does this make sense? I am sorry for the basic question, can someone give me the name of a good book as well? Thanks, Lotta [[alternative HTML version deleted]]
# I am sure there is a better way than this a <- c(1,6,10,11,3,5,10) group <- c(5,5,5,5,9,9,9) my.df <- cbind(a,group) a.5 <- subset(my.df, group==5) median(a.5[,1]) a.9 <- subset(my.df, group==9) median(a.9[,1]) # MASS 4 is a good book On Fri, Aug 1, 2008 at 1:30 PM, Lotta R <lottajane at gmail.com> wrote:> Hi all, > > I have data that looks like > > number|grouping > > > I would like to preform stats for each grouping > > so > > 1|5 > 6|5 > 10|5 > 11|5 > 3|9 > 5|9 > 10|9 > > Say I would like to take the median for above, I should be returned 2 lines, > one for group #5 and one for group #9 > > Does this make sense? > > I am sorry for the basic question, can someone give me the name of a good > book as well? > > Thanks, > Lotta > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at 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. >-- Let's not spend our time and resources thinking about things that are so little or so large that all they really do for us is puff us up and make us feel like gods. We are mammals, and have not exhausted the annoying little problems of being mammals. -K. Mullis
Dear Lotta, Try my.df <- data.frame(a <- c(1,6,10,11,3,5,10), group <- c(5,5,5,5,9,9,9)) tapply(my.df$a,my.df$group,median) 5 9 8 5 See ?tapply and/or ?aggregate for more information. HTH, Jorge On Fri, Aug 1, 2008 at 1:30 PM, Lotta R <lottajane@gmail.com> wrote:> Hi all, > > I have data that looks like > > number|grouping > > > I would like to preform stats for each grouping > > so > > 1|5 > 6|5 > 10|5 > 11|5 > 3|9 > 5|9 > 10|9 > > Say I would like to take the median for above, I should be returned 2 > lines, > one for group #5 and one for group #9 > > Does this make sense? > > I am sorry for the basic question, can someone give me the name of a good > book as well? > > Thanks, > Lotta > > [[alternative HTML version deleted]] > > ______________________________________________ > 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. >[[alternative HTML version deleted]]