I have the following data.table object:
USER active rate day # of elements by hour
4q7C0o 1 1.48 1 c(0, 0, 0, 0, 0, 0, 5, 98, 167, 211, 246)
2BrKY63 1 0.5 3 c(0, 0, 0, 0, 0, 0, 0, 5, 15, 24, 89, 187)
3drUy6I 1 2.58 5 c(0, 0, 0, 0, 0, 0, 0, 0, 1, 112, 265, 309)
G5ALtO 1 1.1 7 c(0, 0, 0, 0, 0, 0, 0, 2, 20, 153, 170)
Where each element of the column # of elements by hour is a list with varying length. I would like to apply the function pexp() to each element of each list (ex. pexp(0, rate = 1.48) to the first element of the first list and pexp(246, rate = 1.48) to the last element of the first list) and if a value less than 'x' occurs then it is displayed in a new column. Something like :
DT[, ifelse(any(lapply( of elements by hour, pexp, rate = rate) < x), 'no.usable','usable' ) ,]
However I don't know how could this be done in a short way in data.table.