Message-ID: <20121013115636.83862ji0vycz675w.mkarhune@webmail.helsinki.fi>
Date: 2012-10-13T08:56:36Z
From: Markku Karhunen
Subject: Loss of dimensions in subsetting arrays
In-Reply-To: <E45CC400-F3DC-4C83-80BB-B57597CCB041@comcast.net>
Ok, apologies.
>
> On Oct 12, 2012, at 2:52 AM, Markku Karhunen wrote:
>
>>
>> Hi all,
>>
>> I've been wondering for a long time why R drops the dimensions of
>> an array/matrix when you try to take a subset of one column. I mean
>> this:
>>
>> dim(A)
>> [1] 2 5 2
>> B=A[1,,]
>> dim(B)
>> 5 2 # so now dim(B)[3] doesn't work
>> C=B[2,]
>> dim(C)
>> NULL # so now nrow(C) doesn't work
>>
>> Typically, you can get rid of this by writing as.matrix,
>> as.array(...) but that generates extra lines of code. This is
>> really annoying. Does anybody know how to turn this behaviour off?
>
> Read the help page for:
>
> ?"[" # especially regarding the drop parameter.
>
> --
>
> David Winsemius, MD
> Alameda, CA, USA
>
>