how to generate elements not included in my sample

Question

This is a bit trivial but how can i generate the set of numbers in x not included in the sample.

x=rnorm(6,0,1)
k=sample(x,3)

Answer 1

Rather than sampling the values, sample the indexes.

set.seed(15)
(x <-rnorm(6,0,1))
# [1]  0.2588229  1.8311207 -0.3396186  0.8971982  0.4880163 -1.2553858
idx <- sample(length(x),3)
(selected <- x[idx])
# [1]  0.8971982 -1.2553858  0.4880163
(notselected <- x[-idx])
# [1]  0.2588229  1.8311207 -0.3396186