R users,
I have a vector of dates
days <- seq(as.Date("2007/1/1"), as.Date("2008/1/31"),
"days")
and I would like to have week numbers from 1 to 52 for each year. How
do I do that? Now I get 00-53 using
format(days, "%W")
> range(format(days, "%W"))
[1] "00" "53"
I have read "Date and Time Classes in R" (R news 01/04 by Gabor
Grothendieck and Thomas Petzoldt) with no help.
Thanks
Lauri
On Tue, Mar 18, 2008 at 7:55 AM, Lauri Nikkinen <lauri.nikkinen at iki.fi> wrote:> R users, > > I have a vector of dates > > days <- seq(as.Date("2007/1/1"), as.Date("2008/1/31"), "days") > > and I would like to have week numbers from 1 to 52 for each year. How > do I do that? Now I get 00-53 using > > format(days, "%W") > > > range(format(days, "%W")) > [1] "00" "53" > > I have read "Date and Time Classes in R" (R news 01/04 by Gabor > Grothendieck and Thomas Petzoldt) with no help. >There are more than 7 * 52 days in a year. Try this which labels the first 7 days as 0, the next as 1, ..., up to 52:> d <- seq(as.Date("2008-01-01"), as.Date("2008-12-31"), "day") > (julian(d) - julian(as.Date(cut(d, "years")))) %/% 7[1] 0 0 0 0 0 0 0 1 1 1 1 1 1 1 2 2 2 2 2 2 2 3 3 3 3 3 3 3 4 4 4 4 4 4 4 5 5 5 5 5 5 5 6 6 6 6 6 6 6 7 [51] 7 7 7 7 7 7 8 8 8 8 8 8 8 9 9 9 9 9 9 9 10 10 10 10 10 10 10 11 11 11 11 11 11 11 12 12 12 12 12 12 12 13 13 13 13 13 13 13 14 14 [101] 14 14 14 14 14 15 15 15 15 15 15 15 16 16 16 16 16 16 16 17 17 17 17 17 17 17 18 18 18 18 18 18 18 19 19 19 19 19 19 19 20 20 20 20 20 20 20 21 21 21 [151] 21 21 21 21 22 22 22 22 22 22 22 23 23 23 23 23 23 23 24 24 24 24 24 24 24 25 25 25 25 25 25 25 26 26 26 26 26 26 26 27 27 27 27 27 27 27 28 28 28 28 [201] 28 28 28 29 29 29 29 29 29 29 30 30 30 30 30 30 30 31 31 31 31 31 31 31 32 32 32 32 32 32 32 33 33 33 33 33 33 33 34 34 34 34 34 34 34 35 35 35 35 35 [251] 35 35 36 36 36 36 36 36 36 37 37 37 37 37 37 37 38 38 38 38 38 38 38 39 39 39 39 39 39 39 40 40 40 40 40 40 40 41 41 41 41 41 41 41 42 42 42 42 42 42 [301] 42 43 43 43 43 43 43 43 44 44 44 44 44 44 44 45 45 45 45 45 45 45 46 46 46 46 46 46 46 47 47 47 47 47 47 47 48 48 48 48 48 48 48 49 49 49 49 49 49 49 [351] 50 50 50 50 50 50 50 51 51 51 51 51 51 51 52 52 attr(,"origin") [1] "1970-01-01"
Looks like you can convert to Julian date with the right origin and then divide by 7, and take modulo 52. Something like: julian(days, origin=days[1]-1) %/% 7 %% 52 That gets you 0-51. You just need to add one to get what you want. (I subtract one from days[1] because it's a Monday. I'm sure you can figure out how to do that programatically.) Andy From: Lauri Nikkinen> > R users, > > I have a vector of dates > > days <- seq(as.Date("2007/1/1"), as.Date("2008/1/31"), "days") > > and I would like to have week numbers from 1 to 52 for each year. How > do I do that? Now I get 00-53 using > > format(days, "%W") > > > range(format(days, "%W")) > [1] "00" "53" > > I have read "Date and Time Classes in R" (R news 01/04 by Gabor > Grothendieck and Thomas Petzoldt) with no help. > > Thanks > Lauri > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > > >------------------------------------------------------------------------------ Notice: This e-mail message, together with any attachme...{{dropped:15}}
365/7 != 52. You have more than 52 weeks in each year. --- Lauri Nikkinen <lauri.nikkinen at iki.fi> wrote:> R users, > > I have a vector of dates > > days <- seq(as.Date("2007/1/1"), > as.Date("2008/1/31"), "days") > > and I would like to have week numbers from 1 to 52 > for each year. How > do I do that? Now I get 00-53 using > > format(days, "%W") > > > range(format(days, "%W")) > [1] "00" "53" > > I have read "Date and Time Classes in R" (R news > 01/04 by Gabor > Grothendieck and Thomas Petzoldt) with no help. > > Thanks > Lauri > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, > reproducible code. >