Using dplyr $ library(dplyr) $ x<-data.frame(Length=c(321,350,340,180,198), ID=c(rep('A234',3),'B123','B225') ) $ x %>% group_by(ID) %>% summarise(m=mean(Length))
On Tue, May 24, 2016 at 3:46 PM, Matthew <mccorm...@molbio.mgh.harvard.edu> wrote: > I have a data frame with 10 columns. > In the last column is an alphaneumaric identifier. > For most rows, this alphaneumaric identifier is unique to the file, > however some of these alphanemeric idenitifiers occur in duplicate, > triplicate or more. When they do occur more than once they are in > consecutive rows, so when there is a duplicate or triplicate or > quadruplicate (let's call them multiplicates), they are in consecutive rows. > > In column 7 there is an integer number (may or may not be unique. does not > matter). > > I want to identify each multiple entries (multiplicates) occurring in > column 10 and then for each multiplicate calculate the mean of the integers > column 7. > > As an example, I will show just two columns: > Length Identifier > 321 A234 > 350 A234 > 340 A234 > 180 B123 > 198 B225 > > What I want to do (in the above example) is collapse all the A234's and > report the mean to get this: > Length Identifier > 337 A234 > 180 B123 > 198 B225 > > > Matthew > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.