Hello R User
dataset<-data.frame(id=c(1,1,2,3,3,3),time=c(3,5,1,2,4,6))
dataset
id time
1 1 3
2 1 5
3 2 1
4 3 2
5 3 4
6 3 6
ids<-unique(dataset$id)
for(id in ids){
+ dataset$time[dataset$id==id]<-c(0,diff(dataset$time[dataset$id==id]))
+ }
dataset
id time
1 1 0
2 1 2
3 2 0
4 3 0
5 3 2
6 3 2
might not be the fastest though.
On 14.12.2012, at 16:51, bibek sharma wrote:
Hello R User, In the sample data given below, time is recorded for each id subsequently. For the analysis, for each id, I would like to set 1st recorded time to zero and thereafter find the difference from previous time. I.e. for ID==1, I would like to see Time=0,3,1,3,6. This needs to be implemented to big data set. Any suggestions are much appreciated! Thanks, Bibek ID Time 1 3 1 6 1 7 1 10 1 16 2 12 2 18 2 19 2 25 2 28 2 30
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