R devel - Mar 2009 - quantile and IQR do not check for numeric input (PR#13631)

This report follows the post

http://tolstoy.newcastle.edu.au/R/e6/devel/09/03/0760.html

where it is shown that quantile() and IQR() do not work as documented.
In fact they do not check for numeric input even if the documentation says :

?quantile
x      numeric vectors whose sample quantiles are wanted. Missing
values are ignored.

?IQR

x 	a numeric vector.
> quantile(factor(1:9))
  0%  25%  50%  75% 100%
   1    3    5    7    9
Levels: 1 2 3 4 5 6 7 8 9
> IQR(factor(1:9))
[1] 4
> R.version
               _
platform       i386-pc-mingw32
arch           i386
os             mingw32
system         i386, mingw32
status         alpha
major          2
minor          9.0
year           2009
month          03
day            26
svn rev        48224
language       R
version.string R version 2.9.0 alpha (2009-03-26 r48224)

--
______________________________________________________

Simone Giannerini
Dipartimento di Scienze Statistiche "Paolo Fortunati"
Universita' di Bologna
Via delle belle arti 41 - 40126 =A0Bologna, =A0ITALY
Tel: +39 051 2098262 =A0Fax: +39 051 232153
http://www2.stat.unibo.it/giannerini/

On Mon, 30 Mar 2009 sgiannerini at gmail.com wrote:
> This report follows the post
>
> http://tolstoy.newcastle.edu.au/R/e6/devel/09/03/0760.html
>
> where it is shown that quantile() and IQR() do not work as documented.
Nothing of the sort is shown! The thread argued that methods for these functions
for ordered factors would be useful.
> In fact they do not check for numeric input even if the documentation says
> :
>
> ?quantile
> x      numeric vectors whose sample quantiles are wanted. Missing
> values are ignored.
>
> ?IQR
>
> x 	a numeric vector.
>
The documentation says that you are not allowed to pass anything except a
numeric vector to quantile() and IQR(). It doesn't, for example, say you can
pass an arbitrary vector that will be checked to see if it is numeric. If you
have code that passes a factor to IQR(), the bug is in that code.

On the other hand, as someone else has since reported, the 'missing values
are ignored' statement in ?quantile is wrong (or at least incomplete).


     -thomas

Thomas Lumley			Assoc. Professor, Biostatistics
tlumley at u.washington.edu	University of Washington, Seattle