And one more yearmon solution. Here z is a zoo series as before: tt <- time(z) aggregate(z, ave(tt, as.yearmon(tt), FUN = max), tail, 1)
On 8/30/07, Gabor Grothendieck <[EMAIL PROTECTED]> wrote: > The last line is wrong (see below for correction): > > On 8/30/07, Gabor Grothendieck <[EMAIL PROTECTED]> wrote: > > The zoo package includes the "yearmon" class to facilitate such > > manipulations. Here are a few solutions assuming you store > > you series in a zoo variable: > > > > # test data > > library(zoo) > > z <- zoo(1001:1100, as.Date(101:200))[-(45:55)] > > > > # Solution 1. tapply produces indexes of last of month > > tt <- time(z) > > z[ c(tapply(seq_along(tt), as.yearmon(tt), tail, 1)) ] > > > > # If we want to create a last variable which corresponds > > # to last in sas then do it this slightly longer way: > > > > # Solution 2 > > tt <- time(z) > > last <- seq_along(tt) %in% tapply(seq_along(tt), as.yearmon(tt), tail, 1) > > z[last] > > > > # Solution 3. another solution with a last variable. f(x) is > > # vector same length as x with all 0's except last element is 1. > > tt <- time(z) > > f <- function(x) replace(0*x, length(x), 1) > > last <- ave(seq_along(tt), as.yearmon(tt), FUN = f) > > z[last] > > This last line should be: > > z[last == 1] > > > > > > In all these solutions the last point in the series is always > > included. > > > > We have not assumed that every day is necessarily included in your > > series but if every day is included then even simpler solutions > > are possible. > > > > On 8/29/07, Shubha Vishwanath Karanth <[EMAIL PROTECTED]> wrote: > > > Hi R users, > > > > > > > > > > > > Is there a function in R, which does some calculation only for the month > > > end in a daily data?... In other words, is there a command in R, > > > equivalent to "last." function in SAS? > > > > > > > > > > > > BR, Shubha > > > > > > > > > [[alternative HTML version deleted]] > > > > > > ______________________________________________ > > > R-help@stat.math.ethz.ch 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. > > > > > > ______________________________________________ R-help@stat.math.ethz.ch 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.
