R has a very powerful array slicing ability that allows for some very slick data processing.
Suppose we have a data.frame “d“, and for every row where d$n_observations < 5 we wish to “NA-out” some other columns (mark them as not yet reliably available). Using slicing techniques this can be done quite quickly as follows.
d[d$n_observations < 5,
qc(mean_cost, mean_revenue, mean_duration)] <- NA