Modification of a Vector based on elements sequence

Question

How is it possible to transform the following vector:

x <- c(0, 0, 0, 1, 0, 3, 2, 0, 0, 0, 5, 0, 0, 0, 8)

into the desired form:

y <- c(1, 1, 1, 1, 3, 3, 2, 5, 5, 5, 5, 8, 8, 8, 8)

Any idea would be highly appreciated.

Answer 1

Here's another approach using only base R:

idx <- x != 0
split(x, cumsum(idx) - idx) <- x[idx]

The x-vector is now:

x
#[1] 1 1 1 1 3 3 2 5 5 5 5 8 8 8 8