[R] having trouble extracting week from chron object

[Christopher W Ryan]

Running R 2.13.1 on Windows XP.
I would like to get week of the year (1-52) for each date.

library(chron)
dts <- dates(c("02/27/92", "02/27/92", "01/14/92","02/28/92", "02/01/92"))
dts
dts.chron <- as.chron(dts)
dts.chron
class(dts.chron)
# all of these component extractions work:
months(dts.chron)
weekdays(dts.chron)
years(dts.chron)
quarters(dts.chron)
# but weeks() doesn't seem to work
weeks(dts.chron)

?chron tells me: . . . The functions days(), months(), quarters(),
years(), weeks(), weekdays(), hours(), minutes(), and seconds() take
any chron object as input and extract the corresponding time interval
. . . .

Any advice?

Thanks.

Chris Ryan
SUNY Upstate Medical University Clinical Campus at Binghamton
Binghamton, NY