**Subject: **Re: tapply not simplifying to vector? (PR#320)

*maechler@stat.math.ethz.ch*

**Date: **Thu 11 Nov 1999 - 20:54:10 EST

**Next message:**Peter Dalgaard BSA: "Re: tapply not simplifying to vector? (PR#320)"**Previous message:**maechler@stat.math.ethz.ch: "Re: dimname'less array breaks apply (PR#318)"**Maybe in reply to:**mcw@ln.nimh.nih.gov: "tapply not simplifying to vector? (PR#320)"**Next in thread:**Peter Dalgaard BSA: "Re: tapply not simplifying to vector? (PR#320)"**Maybe reply:**maechler@stat.math.ethz.ch: "Re: tapply not simplifying to vector? (PR#320)"

Message-Id: <199911111054.LAA01914@pubhealth.ku.dk>

*>>>>> "MatW" == Matthew Wiener <mcw@ln.nimh.nih.gov> writes:
*

* MatW> The help file for tapply says that if simplify is true, and the
*

* MatW> result of the calculation is always a scalar, then tapply will
*

* MatW> return a vector.
*

* MatW> Nonetheless:
*

* >> t1 <- tapply(runif(10), rep(1:5, 2), mean)
*

* >> is.vector(t1)
*

* R> [1] FALSE
*

* >> is.array(t1)
*

* R> [1] TRUE
*

<....>

all correct.

The question really is if the bug is in the code or the documentation.

Here you get a 1D array, something quite rare (but appearing more and more

in recent discussions...).

One could argue that the current behavior of tapply() to always return an

array if simplify = TRUE is more consistent, than what the doc says should

happen (coercing 1D arrays to vectors).

Otoh, the protoype *does* return a vector in this case,

and 1D arrays can be a pain... in other places.

I'm pro fixing this.

and I'll do if I don't hear protests..

* MatW> <....>
*

* MatW> Hope this report helps.
*

yes indeed, thank you!

R's quality is growing partly because of such fine bug reports!

* MatW> Thanks for the terrific software.
*

you're welcome!

Martin Maechler <maechler@stat.math.ethz.ch> http://stat.ethz.ch/~maechler/

Seminar fuer Statistik, ETH-Zentrum LEO D10 Leonhardstr. 27

ETH (Federal Inst. Technology) 8092 Zurich SWITZERLAND

phone: x-41-1-632-3408 fax: ...-1228 <><

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**Next message:**Peter Dalgaard BSA: "Re: tapply not simplifying to vector? (PR#320)"**Previous message:**maechler@stat.math.ethz.ch: "Re: dimname'less array breaks apply (PR#318)"**Maybe in reply to:**mcw@ln.nimh.nih.gov: "tapply not simplifying to vector? (PR#320)"**Next in thread:**Peter Dalgaard BSA: "Re: tapply not simplifying to vector? (PR#320)"**Maybe reply:**maechler@stat.math.ethz.ch: "Re: tapply not simplifying to vector? (PR#320)"

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