Hello R community,
I am hoping for some help with the following problem.
I have a data frame containing various groups. These groups are identified
by a grouping variable. I would like to add a sequential ID number to each
group to later sort these individuals within each group by this ID number.
Here is what the final result should look like:
ID group var2
1 1 1
2 1 2
3 1 3
4 1 4
1 2 5
2 2 6
3 2 7
4 2 8
5 2 9
1 3 10
2 3 11
3 3 12
4 3 13
5 3 14
I have created the following code to loop through this and compare a given
row with the following row for the grouping variable. If a given row would
be different from the then following row, the ID number would be reset and I
would start counting up again. The problem that I am encountering that at
the bottom of the data frame the if statement runs out of a condition
against which to compare the last row.
Here is what I did:
group<- c(1,1,1,1,2,2,2,2,2,3,3,3,3,3,3)
var2<- c(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15)
data<-data.frame(group, var2)
data
#IDN is the desired ID number by group
IDN <-numeric(length(test$var2))
IDN
for (i in 1:(length(data$group))) {
if(data[i,1] < (length(data$group))){
if(data[i,1] == data[i+1,1]){
IDN[i]<- sum(IDN[i-1],1)}
else{
IDN[i]<- -55} #for now an arbitrary value
}
if(data[i,1] == (length(data$group))) {
IDN[i] <- 99 #for now an arbitrary value
}
}
IDN
Is there maybe an easier way to do this? Any thoughts would be very
appreciated since I am running out of ideas.
Thanks
Alexander
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