From Martin Maechler <maechler@stat.math.ethz.ch>  Wed May  3 11:24:23 2000
From: Martin Maechler <maechler@stat.math.ethz.ch> (Martin Maechler)
Date: Wed, 3 May 2000 12:24:23 +0200 (CEST)
Subject: [Rd] print() "bug" for arrays with 0 columns
Message-ID: <14607.65111.375233.678442@lynne.ethz.ch>

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