Re: [R] Elementary Help

Hi, Based on the information you provided, the solution should be the one I provided earlier.  Otherwise, I must have misunderstood your question.  In your first post, you mentioned the IDs range from 5:200.   So, the question is not clear. dat1<- read.table(text=" timeSec pupilId pupilName 13

Re: [R] Elementary Help

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

Re: [R] 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