How can I group days into weeks?

Question

In R, how can I associate between a vector of dates (days) and weeks?

Edit: \"weeks\" should be the week index within the date range and not within the year. My apol

Answer 1

Do you just want the number of completed 7 day intervals since the first record?

dvec <- as.Date("2001-04-01")+0:90
dweek <- as.numeric(dvec-dvec[1]) %/% 7
dweek[1:21]
# [1] 0 0 0 0 0 0 0 1 1 1 1 1 1 1 2 2 2 2 2 2 2