Cumulative sum for positive numbers only

Question

I have this vector :

x = c(1,1,1,1,1,0,1,0,0,0,1,1)

And I want to do a cumulative sum for the positive numbers only. I should have the fol

Answer 1

Here's a possible solution using data.table v >= 1.9.5 and its new rleid funciton

library(data.table)
as.data.table(x)[, cumsum(x), rleid(x)]$V1
## [1] 1 2 3 4 5 0 1 0 0 0 1 2