# [Rd] print() "bug" for arrays with 0 columns

Martin Maechler Martin Maechler <maechler@stat.math.ethz.ch>
Wed, 3 May 2000 12:24:23 +0200 (CEST)

```The "bug" is that it doesn't print anything;
one might argue that this is not a bug, since such an array *is* empty,
but I don't buy that argument.

It *does* print if #{columns} (= last dimension) > 0 :

> array(NA,dim=c(2,0))
> array(NA,dim=c(2,1,0))

> array(NA,dim=c(0,2))
[,1] [,2]
> array(NA,dim=c(0,2,1))
, , 1

[,1] [,2]

> array(NA,dim=c(0,0,1))
, , 1

S-plus 5.1 does better for matrices
but worse (at least in some cases) for higher-rank arrays :

> array(NA,dim=c(0,2))
logical matrix: 0 rows, 2 columns.
> array(NA,dim=c(0,0,1))
Problem in 1:(length(x)/nm): Missing value where number needed
Use traceback() to see the call stack
> array(NA,dim=c(0,1,0))
Problem in 1:(length(x)/nm): Missing value where number needed
Use traceback() to see the call stack
> array(NA,dim=c(1,0,0))
Problem in 1:(length(x)/nm): Missing value where number needed
Use traceback() to see the call stack
> array(NA,dim=c(1,2,0))

, ,
[,1] [,2]
[1,]   NA   NA

, ,
[,1] [,2]
[1,]   NA   NA
>

---------

What should we be doing instead of the current behavior?
Typing a "sentence" ---as S+5 does for matrices--- seems quite reasonable;
I would want to do this in *all* cases where one of the dimensions is 0.

Other suggestions?

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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