I have a vector of integers and I want to filter it by eliminating the components that are "isolated". What do I mean by "isolated"? those components that does not lie in an 4-neighbourhood of other component. The components in the vector are ordered increasingly, and there are no repetitions.
For example if I have
c(1,2,3,8,15,16,17) then I need to eliminate
8 because is not in a 4-neighbourhood of other element.
I've tried applying
for (p in 1:(length(index)-2)) if((index
index is my vector of interest, but there's some problem with the logical condition. Could you please give me some hints?
Thanks in advance.
You can achieve it with a combination of
x[colSums(abs(outer(x, x, `-`)) >= 4) == length(x)-1] # 8
To eliminate the values, we can do,
i1 <- colSums(outer(x, x, FUN = function(i, j) abs(i - j) >= 4)) == length(x) - 1 x[!i1] # 1 2 3 15 16 17
x <- c(1,2,3,8,15,16,17)