For each element of
nvec the sequence
is created. These are concatenated and the result returned.
a non-negative integer vector each element of which specifies the end point of a sequence.
Earlier versions of
sequence used to work for 0 or negative inputs as
seq(x) == 1:x.
sequence <- function(nvec) unlist(lapply(nvec, seq_len))
and it mainly exists in reverence to the very early history of R.