[Rd] seq.Date requires by

Gabor Grothendieck ggrothendieck at myway.com
Sat Dec 4 03:50:20 CET 2004

Oops.  I had my own as.Date routines loaded.  (These
will be made available in the next version of zoo
but here they are in the meantime.)

If you want to get the as.Date(xD:yD) and similar
to come out you should define these:

as.Date.numeric <- function (x, ...) 
           structure(floor(x + 0.001), class = "Date")
as.Date.integer <- function (x, ...) 
           structure(x, class = "Date")

Date:   Fri, 3 Dec 2004 21:42:37 -0500 (EST) 
From:   Gabor Grothendieck <ggrothendieck at myway.com>
To:   <vograno at evafunds.com>, <r-devel at stat.math.ethz.ch> 
Subject:   RE: [Rd] seq.Date requires by 


Don't know the answer to your question but note
that chron can do it without by=.

xD <- as.Date("1996-01-01")
yD <- as.Date("1996-12-01")
xc <- chron(xD)
yc <- chron(yD)

seq(xc, yc)

# Also one can do this in either chron or Date:


Date: Fri, 3 Dec 2004 11:29:08 -0800 
From: Vadim Ogranovich <vograno at evafunds.com>
To: <r-devel at stat.math.ethz.ch> 
Subject: [Rd] seq.Date requires by 


What is the reason for seq.Date to require the 'by' argument and not to
default it to 1 in the example below?

> seq(from=as.Date("1996-01-01"), to=as.Date("1996-12-01"))
Error in seq.Date(from = as.Date("1996-01-01"), to =
as.Date("1996-12-01")) : 
exactly two of `to', `by' and `length.out' / `along.with' must be

This is R-1.9.1, but I haven't seen anything pertaining in the release
notes of 2.0.x.


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