Question

This is the reproducible code:

a <- rep(1, 20)
a[c(1, 12, 15)] <- 0
b <- which(a == 0)
set.seed(123)
d <- round(runif(17) * 100)

I would like to append 0s to d to get the following result:

[1]  0 29 79 41 88 94  5 53 89 55 46  0 96 45  0 68 57 10 90 25

that is equal to d after appending 0s to each element which has index equal to b - 1.

I’ve seen append() accepts just one single “after” value, not more than one.

How could I do?

Please, keep in mind I cannot change the length of d because it is supposed it’s the ouput of a quite long function, not a simple random sequence like in this example.

Answer 1

You can use negative subscripting to assign the non-zero elements to a new vector.

D <- numeric(length(c(b,d)))
D[-b] <- d
D
# [1]  0 29 79 41 88 94  5 53 89 55 46  0 96 45  0 68 57 10 90 25