Hi Jim and Jeff, Thanks for the quick help!
Sorry I didn't state the question clearly: I want the difference between 'neutral' and 'negative' for each subject. And another person offered a solution for it: aggregate(cbind(QM, yi) ~ subject, data = mydata, FUN = diff) On Thu, Jul 28, 2016 at 4:53 PM, jim holtman <jholt...@gmail.com> wrote: > Not sure what you mean by "nice way", but here is a dplyr solution: > >> library(dplyr) >> mydata <- read.table(text = "subject QM emotion yi > + s1 75.1017 neutral -75.928276 > + s2 -47.3512 neutral -178.295990 > + s3 -68.9016 neutral -134.753906 > + s1 17.2099 negative -104.168312 > + s2 -53.1114 negative -182.373474 > + s3 -33.0322 negative -137.420410", header = TRUE) >> agg <- mydata %>% > + group_by(subject) %>% > + summarise(QM = mean(QM), > + yi = mean(yi) > + ) >> >> >> agg > # A tibble: 3 x 3 > subject QM yi > <fctr> <dbl> <dbl> > 1 s1 46.1558 -90.04829 > 2 s2 -50.2313 -180.33473 > 3 s3 -50.9669 -136.08716 > > > > Jim Holtman > Data Munger Guru > > What is the problem that you are trying to solve? > Tell me what you want to do, not how you want to do it. > > On Thu, Jul 28, 2016 at 4:40 PM, Gang Chen <gangch...@gmail.com> wrote: >> >> With the following data in data.frame: >> >> subject QM emotion yi >> s1 75.1017 neutral -75.928276 >> s2 -47.3512 neutral -178.295990 >> s3 -68.9016 neutral -134.753906 >> s1 17.2099 negative -104.168312 >> s2 -53.1114 negative -182.373474 >> s3 -33.0322 negative -137.420410 >> >> I can obtain the average between the two emotions with >> >> mydata <- read.table('clipboard', header=TRUE) >> aggregate(mydata[,c('yi', 'QM')], by=list(subject=mydata$subject), mean) >> >> My question is, what is a nice way to get the difference between the >> two emotions? >> >> Thanks, >> Gang >> >> ______________________________________________ >> 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. > > ______________________________________________ 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.