How can I vectorize access to neighbour vector elements in R?

Question

I have the following vector

 v = c(F, F, F, T, F, F, F, F, F, T, F, F, F)

How can I change v so that the previous 2 elements and the following

Answer 1

Here's another attempt. It seems to work on your data and also when the first element is TRUE.

as.logical(rowSums(embed(c(FALSE, FALSE, v, FALSE, FALSE), 5)))
#  [1] FALSE  TRUE  TRUE  TRUE  TRUE  TRUE FALSE  TRUE  TRUE  TRUE  TRUE  TRUE FALSE

# another attempt with beginning and end TRUE
v = c(T, F, F, F, F, F, T, F, F, F, F, F, T)
#  [1]  TRUE  TRUE  TRUE FALSE  TRUE  TRUE  TRUE  TRUE  TRUE FALSE  TRUE  TRUE  TRUE

---

Similar to @flodel's idea, one could create a function here as:

rollOR <- function(vec, dir="both", dist=2) {
    stopifnot(dir %in% c("left", "right", "both"))
    stopifnot(dist >= 0)
    stopifnot(is.logical(vec))

    cvec <- rep(FALSE, dist)
    switch(dir, 
        both = {
            vec <- c(cvec, vec, cvec)
            dist <- dist * 2 + 1
        }, 
        left = {
            vec <- c(vec, cvec)
            dist <- dist + 1
        },
        right = {
            vec <- c(cvec, vec)
            dist <- dist + 1
        })

    as.logical(rowSums(embed(vec, dist)))
}   
# direction both sides
rollOR(v, "both", 2)
# [1] FALSE  TRUE  TRUE  TRUE  TRUE  TRUE FALSE  TRUE  TRUE  TRUE  TRUE  TRUE FALSE

# left alone
rollOR(v, "left", 2)
# [1] FALSE  TRUE  TRUE  TRUE FALSE FALSE FALSE  TRUE  TRUE  TRUE FALSE FALSE FALSE

# right alone
rollOR(v, "right", 2)
# [1] FALSE FALSE FALSE  TRUE  TRUE  TRUE FALSE FALSE FALSE  TRUE  TRUE  TRUE FALSE