Collapsing data frame by selecing one row per group
- by jkebinger
I'm trying to collapse a data frame by removing all but one row from each group of rows with identical values in a particular column. In other words, the first row from each group.
For example, I'd like to convert this
> d = data.frame(x=c(1,1,2,4),y=c(10,11,12,13),z=c(20,19,18,17))
> d
x y z
1 1 10 20
2 1 11 19
3 2 12 18
4 4 13 17
…