[R] function ave() with seq_along returning char sequence instead of numeric

[Nordlund, Dan (DSHS/RDA)]

Jeff,

Thanks for the response.  You are right of course. I went back and reread the help page.  I guess I just glossed over the 'x is numeric' statement because the default FUN was the mean, and seq_along doesn't care about type.  I should know better than to disregard what I read in the help pages.  But you are right, using any numeric vector of appropriate size as the first argument does what I need.

Dan

Daniel Nordlund, PhD
Research and Data Analysis Division
Services & Enterprise Support Administration
Washington State Department of Social and Health Services


> -----Original Message-----
> From: Jeff Newmiller [mailto:jdnewmil at dcn.davis.ca.us]
> Sent: Monday, October 31, 2016 4:34 PM
> To: Nordlund, Dan (DSHS/RDA); r-help at r-project.org
> Subject: Re: [R] function ave() with seq_along returning char sequence
> instead of numeric
> 
> The help page describes the first argument x as a numeric... it is not
> designed to accept character, so the fact that you get anything even close to
> right is just a bonus.
> 
> As the doctor says, "if it hurts, don't do that".
> 
> ave( rep( 1, length( v ), v, FUN=seq_along )
> --
> Sent from my phone. Please excuse my brevity.
> 
> On October 31, 2016 3:29:01 PM PDT, "Nordlund, Dan (DSHS/RDA)"
> <NordlDJ at dshs.wa.gov> wrote:
> >Given  the following R statements
> >
> >v <-  c('a', 'a', 'a', 'b', 'b', 'b', 'c', 'c', 'c', 'c') ave(v,
> >list(v), FUN=seq_along)  [1] "1" "2" "3" "1" "2" "3" "1" "2" "3" "4"
> >
> >I was expecting to get a numeric vector back.  I apparently have missed
> >something in the documentation.  If vector v is character, then the
> >numeric sequence is converted to character before returning.  I can
> >work around by doing something like
> >
> >ave(seq_along(v), list(v), FUN=seq_along)  [1] 1 2 3 1 2 3 1 2 3 4
> >
> >Is the work around the best way to go, or have I missed an option in
> >the documentation?
> >
> >
> >Thanks,
> >
> >Dan
> >
> >Daniel Nordlund, PhD
> >Research and Data Analysis Division
> >Services & Enterprise Support Administration Washington State
> >Department of Social and Health Services
> >
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