[R] Re: dates in chron package, split warning message

[Steve Su]

Dear All,

Thank you Professor Ripley for your prompt and helpful reply.

I propose the answer to my question on cut.dates function is do the
following:

months = chron(julian(mdy$m,
1, mdy$y, origin = orig),origin=orig)-1, years = chron(julian(1, 1,
mdy$y, origin = orig),origin=orig)-1)

in the cut.dates function.

As to my second query, I modify the split function by adding the following
line in the split.default function:

if(is.matrix(x)){
return(.Internal(split(c(x),factor(rep(f,length=length(c(x)))))))

which works well for my needs.

Thank you for your attention.

Steve.





----- Original Message -----
From: "Prof Brian Ripley" <ripley at stats.ox.ac.uk>
To: "Steve Su" <s.su at qut.edu.au>
Cc: "R Help" <r-help at stat.math.ethz.ch>
Sent: Thursday, May 22, 2003 4:44 PM
Subject: Re: [R] Re: dates in chron package, split warning message


> On Thu, 22 May 2003, Steve Su wrote:
>
> > > > I am currently using R for windows.
> > > >
> > > > I am wondering why the dates command in chron package does not work
in
> > the
> > > > following situation:
> > > >
> > > > cut(dates(c(23,45,67),origin=c(1,1,2004)),"months")
> > > >
> > > > but will work for:
> > > >
> > > > cut(dates(c(23,45,67),origin=c(1,1,2004)),"days")
> > > > cut(dates(c(23,45,67),origin=c(1,1,2004)),"weeks")
>
> The dates function (not command) does work of course.  It's cut.dates
> which fails.  The short answer to you is this is a great opportunity to
> learn to debug R functions, and the hint is that the line
>
>     from <- switch(by, days = from,
> weeks = (from - day.of.week(mdy$m,mdy$d, mdy$y) +
as.numeric(start.on.monday)),
>         months = chron(julian(mdy$m, 1, mdy$y, origin = orig)),
>         years = chron(julian(1, 1,mdy$y, origin = orig)))
>
> contains two bugs.
>
> > > > My second query is rather trivial but I am wondering why warning
> > messages
> > > > were given when using the split in this manner:
> > > >
> > > > split(matrix(1:12,nrow=4),c(1,1,2,3)) # Which does what I want it to
do.
> > > >
> > > > and no warning messages were given in Splus6 for example?
>
> Try reading the help pages in each system.  They do not define split in
> the same way, and your usage is incorrect in R but not in S-PLUS 6.1.
>
> --
> Brian D. Ripley,                  ripley at stats.ox.ac.uk
> Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
> University of Oxford,             Tel:  +44 1865 272861 (self)
> 1 South Parks Road,                     +44 1865 272866 (PA)
> Oxford OX1 3TG, UK                Fax:  +44 1865 272595
>