My data:
id<-c(1,1,1,1,1,1,1,2,2,2)
start<-c(0,1,3,5,7,8,10,0,0,1)
end<-c(1,3,5,7,8,9,12,0,1,4)
mydata<-data.frame(id,start,end)
Question:
What code would I use to indicate that rows 1-7 are linked to the unique id(1), and rows 8-10 are linked to id(2)? The output should look as follows:
Indexes[1:2]
$ '1'
1 2 3 4 5 6 7
$ '2'
8 9 10`
Attempt:
I have looked around StackOverflow but don't really see this being done. I did try
split(mydata,mydata$id)
I know that if I say:
which(mydata$id==1)
It will tell me rows 1-7. But don't know how to use this to my advantage to get the output above.
but that certainly doesn't work.
You were almost there. split can be used on the rownames as well. Since they'll be character values, you coerce them to numeric with as.numeric
> Indexes <- split(as.numeric(rownames(mydata)), mydata$id)
> Indexes[1:2] ## or just 'Indexes' for your sample data
## $`1`
## [1] 1 2 3 4 5 6 7
## $`2`
## [1] 8 9 10