Different according to the function's type
argument. If
"both_num"
(the default), a vector of 6-digit integers is returned, in a
YYYYWW format. If "week"
or "year"
, only the week number or year is
returned, respectively. If "both_text"
, then a character vector of the same
length as x
is returned, containing both the year and week number, seperated
by sep
, and inverted if inv=TRUE
. Finally, if type="matix"
, both
year and week numbers are returned in a two-column matrix, with the columns named as
in colnames
.