There seems to be a bug in seq.Date such that it will not allow the user to pass in length.out =3D NULL, despite the fact that this is the = default argument.
For example: > dt1 <- as.Date("2004-12-31") > dt2 <- as.Date("2005-12-31") > seq.Date(dt1, dt2, length.out =3D NULL, by =3D "month") Error in seq.Date(dt1, dt2, length.out =3D NULL, by =3D "day") :=20 'length.out' must be of length 1 This might be an issue if I want to wrap seq.Date in another function that reports or modifies on length.out. For instance, suppose I want to create a simple function that simply reports when length.out is NULL (or missing), as below, but otherwise works identically to seq.Date. FUN <- function(to, from, length.out =3D NULL, by, ...) { if (is.null(length.out)) cat("length.out is missing\n") seq.Date(to, from, length.out =3D length.out, by =3D by, ...) } > seq.Date(dt1, dt2, by =3D "month") [1] "2004-12-31" "2005-01-31" "2005-03-03" "2005-03-31" "2005-05-01" [6] "2005-05-31" "2005-07-01" "2005-07-31" "2005-08-31" "2005-10-01" [11] "2005-10-31" "2005-12-01" "2005-12-31" > FUN(dt1, dt2, by =3D "month") length.out is missing Error in seq.Date(dt1, dt2, length.out =3D NULL, by =3D "day") :=20 'length.out' must be of length 1 I believe the patch to fix this error is as follows (on R2.4.0(alpha) Revision 39430) - } else if (!missing(length.out)) { + } else if (!missing(length.out) && !is.null(length.out)) { Another (perhaps better) patch would be to not have NULL be the default for length.out. HTH, Robert Robert McGehee Quantitative Analyst Geode Capital Management, LLC 53 State Street, 5th Floor | Boston, MA | 02109 Tel: 617/392-8396 Fax:617/476-6389 mailto:[EMAIL PROTECTED] This e-mail, and any attachments hereto, are intended for us...{{dropped}} ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel