[R] Inconsistency among mean, median, max, var

ripley@stats.ox.ac.uk ripley at stats.ox.ac.uk
Sat Mar 30 21:25:02 CET 2002

On Sat, 30 Mar 2002 ggrothendieck at yifan.net wrote:

> I found a strange inconsistency:

Well, these do work as documented, and I don't find it even ordinarily

> If m is a matrix and d is a data frame then
> - mean(m), median(m), max(m) and max(d) all return a single value
> but
> - mean(d) returns the column means
> - median(d) fails
> - both var(m) and var(d)  return the variance covariance matrix
> You pretty much have to experiment to figure this out since much of this
> behavior is not readily obvious from the help files.

I don't think that is even 1% fair:

?mean clearly says what it does for a data frame.
?median clearly says it only works for numeric vectors.
?var clearly says that it works for `a numeric vector, matrix or data

Whatever is the problem with that?

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 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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