Problem: How can I fill backwards all rows in a group before an occurrence of a certain value. I am not trying to fill in NA or missing value using zoo na.locf. In the following I would like to fill all previous rows in A with 1.00 before the 1.00 occurs by each ID group, ideally using dplyr.
Input:
data<- data.frame(ID=c(1,1,1,1,2,2,2,3,3,3,4,4,4,4,4),
time=c(1,2,3,4,1,2,3,1,2,3,1,2,3,4,5),
A=c(0.10,0.25,1,0,0.25,1,0.25,0,1,0.10,1,0.10,0.10,0.10,0.05))
ID time A
1 1 0.10
1 2 0.25
1 3 1.00
1 4 0.00
2 1 0.25
2 2 1.00
2 3 0.25
3 1 0.00
3 2 1.00
3 3 0.10
4 1 1.00
4 2 0.10
4 3 0.10
4 4 0.10
4 5 0.05
Desired output:
ID time A
1 1 1.00
1 2 1.00
1 3 1.00
1 4 0.00
2 1 1.00
2 2 1.00
2 3 0.25
3 1 1.00
3 2 1.00
3 3 0.10
4 1 1.00
4 2 0.10
4 3 0.10
4 4 0.10
4 5 0.05