HI, Probably, this is the case. It is better to provide a reproducible example data as mentioned in the posting guide. set.seed(24) dat1<- data.frame(ID=c(1:3,5:8,10:14),value=sample(1:40,12,replace=TRUE)) IDs<- 1:14 #the possible ID list setdiff(IDs,dat1$ID) #[1] 4 9 length(setdiff(IDs,dat1$ID)) #[1] 2 A.K.
Hi, Unfortunately somehow it won't help. The unused values are not NA, the unused values are simply not there. Since these are student Ids, for instance there is no 4,8,9 etc... I need to find out which of these are not there. ----- Original Message ----- From: arun <smartpink...@yahoo.com> To: R help <r-help@r-project.org> Cc: Sent: Tuesday, June 18, 2013 10:32 AM Subject: Re: Elementary Help Hi, May be this helps: set.seed(24) dat1<- data.frame(ID=1:200,value=sample(c(5:200,NA),200,replace=TRUE)) which(is.na(dat1$value)) #[1] 56 146 184 sum(which(is.na(dat1$value))) #Not clear about the 2nd part of the question #[1] 386 sum(is.na(dat1$value)) #[1] 3 table(is.na(dat1$value)) #FALSE TRUE # 197 3 A.K. >I am totally new to R, therefore probably this question will be very easy for most of you. I have a range of values in a column ranging from 5 to 200. >Some of the values are missing, that is, not all student numbers are there. How do I find which are these missing numbers and obtain the sum of >these integers? ______________________________________________ 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.
