[R] Array dimnames
Domenico Vistocco
vistocco at unicas.it
Sat Dec 15 19:24:07 CET 2007
dave mitchell wrote:
> Dear all,
> Possibly a rudimentary question, however any help is greatly appreciated. I
> am sorting a large matrix into an array of dim(p(i),q,3). I put each entry
> into a corresponding matrix (1 of the 3) based on some criteria. I figure
> this will assist me in condensing code as I can loop through the 3rd
> dimension of the array instead of generating 3 separate matrices and using
> the same block of code 3 times. My question is how to get the colnames of
> the 3 nested matrices in the array to match the colnames of the data
> matrix. In other words...
>
Denoting with array3d the array and with matrix2d the data matrix:
colnames(array3d)=colnames(array3d)
Otherwise, using dimnames:
dimnames(array3d)=list(NULL,colnames(array3d),NULL)
You can operate using the "[" operator, that is:
array3d[,"region",] to extract the region columns from each dimension.
You obtain the same effect using the column number, i.e.
array3d[,2,]
domenico
> DATA:
> Exp region Qty Ct ...q
> 1 S CB 3.55 2.15 .
> 2 S TG 4.16 2.18 .
> 3 C OO 2.36 3.65 .
> 4 C . . .
> . . . . .
> . . . . .
> . . . . .
> p ...........................
>
>
>
> ARRAY
> 1
> [,1] [,2] [,3] [,4]...q
> 1 SOME DATA WILL FILL THIS .
> 2 . . . .
> 3 . . . .
> 4 . . . .
> . . . . .
> . . . . .
> . . . . .
> P(1) ...........................
>
> 2
> [,1] [,2] [,3] [,4]...q
> 1 SOME DATA WILL FILL THIS .
> 2 . . . .
> 3 . . . .
> 4 . . . .
> . . . . .
> . . . . .
> . . . . .
> P(2) ...........................
> 3
> [,1] [,2] [,3] [,4]...q
> 1 SOME DATA WILL FILL THIS .
> 2 . . . .
> 3 . . . .
> 4 . . . .
> . . . . .
> . . . . .
> . . . . .
> P(3) ...........................
>
> Again, how to get those [,1], [,2]... to read (and operate) in the same
> fashion as the column names in the data matrix? Also, am I interpreting the
> dimensions of the array incorrectly? Please feel free to post any helpful
> links on the subject, as I have found "dimnames" and "array" in the R-help
> documentation unhelpful. Any help is greatly appreciated.
>
> Dave Mitchell
> Undergraduate: Statistics and Mathematics,
> University of Illinois, Urbana-Champaign
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
>
More information about the R-help
mailing list