Hi, Try this: dattrial<-data.frame(a=c(1,NA,rnorm(4,10)), Week=c(3,3,3,4,4,4)) aggregate(dattrial$a,list(dattrial$Week),function(x) sum(is.na(x))) # Group.1 x #1 3 1 #2 4 0 #or ddply(dattrial,.(Week),summarize, sum(is.na(a))) # Week ..1 #1 3 1 #2 4 0
#or list1<-split(dattrial,dattrial$Week) unlist(lapply(lapply(list1,`[`, 1),function(x) sum(is.na(x)))) #3 4 #1 0 A.K. ----- Original Message ----- From: Tagmarie <ramga...@gmx.net> To: r-help@r-project.org Cc: Sent: Monday, September 17, 2012 6:03 AM Subject: [R] count NAs per week Even though I work with R since a year or so I still struggle with simple problems. I hope someone can help me with this. Been trying for days and am a little frustrated now. I have a data frame somewhat like the one bellow: dattrial<-data.frame(a=c(1,NA,rnorm(4,10)), Week=c(3,3,3,4,4,4)) I want to know how many NAs I have in week 3 and in week 4. -- View this message in context: http://r.789695.n4.nabble.com/count-NAs-per-week-tp4643351.html Sent from the R help mailing list archive at Nabble.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.
