HI, Try this: df1<-read.table(text=" FID MID IID EW_INCU EW_17.5 EMW EEratio 1 4621 TWF2H5 45.26 NA 15.61 NA 1 4621 TWF2H6 48.02 44.09 13.41 0.3041506 2 4630 TWF2H19 51.44 47.81 NA NA 2 4631 TWF2H21 NA 52.72 16.70 0.3167678 2 4632 TWF2H22 55.70 50.45 16.48 0.3266601 2 4633 TWF2H23 44.42 40.89 12.96 0.3169479 ",sep="",header=TRUE,stringsAsFactors=FALSE) aggregate(df1[,4:7],by=list(df1[,1]),function(x) mean(x,na.rm=T)) # Group.1 EW_INCU EW_17.5 EMW EEratio #1 1 46.6 44.1 14.5 0.304 #2 2 50.5 48.0 15.4 0.320
----- Original Message ----- From: Yao He <yao.h.1...@gmail.com> To: r-help@r-project.org Cc: Sent: Saturday, December 15, 2012 10:44 PM Subject: [R] how to handle NA values in aggregate() Dear All: I am trying to calculate four columns' means in a dataframe like this: FID MID IID EW_INCU EW_17.5 EMW EEratio 1 4621 TWF2H5 45.26 NA 15.61 NA 1 4621 TWF2H6 48.02 44.09 13.41 0.3041506 2 4630 TWF2H19 51.44 47.81 NA NA 2 4631 TWF2H21 NA 52.72 16.70 0.3167678 2 4632 TWF2H22 55.70 50.45 16.48 0.3266601 2 4633 TWF2H23 44.42 40.89 12.96 0.3169479 I try this code > aggregate(df[,4:7],df[,1],mean) But I couldn't set the agrument na.rm=T in the mean() function,so the results are all NAs Please tell me how to handle NA values in the use of aggregate() Thanks a lot Yao He ————————————————————————— Master candidate in 2rd year Department of Animal genetics & breeding Room 436,College of Animial Science&Technology, China Agriculture University,Beijing,100193 E-mail: yao.h.1...@gmail.com —————————————————————————— ______________________________________________ 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. ______________________________________________ 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.
