Hi, R is having the following weird behavior and I am not sure if that is a feature or a bug: I am working on the following "3D" array:> bIm, , 1 [,1] [1,] TRUE [2,] TRUE [3,] TRUE [4,] TRUE [5,] TRUE> class(bIm)[1] "array"> dim(bIm)[1] 5 1 1 When I try to get the first 2D subarray, the whole thing folds into a vector:> bIm[,,1][1] TRUE TRUE TRUE TRUE TRUE This causes a lot of trouble in the R code as one would have expected to get a 2D array but ends up with this "logical" vector. Is this the way it was meant to be? Does not this behavior bother anyone else besides me? Thanks for the help, Firas.
On Tue, 1 Aug 2006, Swidan, Firas wrote:> Hi, > > R is having the following weird behavior and I am not sure if that is a > feature or a bug:It's a feature. And a very old FAQ (#7.5)> I am working on the following "3D" array: > >> bIm > , , 1 > > [,1] > [1,] TRUE > [2,] TRUE > [3,] TRUE > [4,] TRUE > [5,] TRUE > >> class(bIm) > [1] "array" >> dim(bIm) > [1] 5 1 1 > > When I try to get the first 2D subarray, the whole thing folds into a > vector: > >> bIm[,,1] > [1] TRUE TRUE TRUE TRUE TRUE > > This causes a lot of trouble in the R code as one would have expected to get > a 2D array but ends up with this "logical" vector. > > Is this the way it was meant to be? Does not this behavior bother anyone > else besides me?Yes, it is the way it was meant to be. It has bothered other people, but the alternatives are probably worse. -thomas
Hi,
Try this:
bIm <-array(rep(TRUE,5),c(5,1,1))
bIm[,,1]
#[1] TRUE TRUE TRUE TRUE TRUE
bIm[,,1,drop=FALSE]
, , 1
[,1]
[1,] TRUE
[2,] TRUE
[3,] TRUE
[4,] TRUE
[5,] TRUE
See ?'[' for details on drop
drop: For matrices and arrays. If 'TRUE' the result is coerced to
the lowest possible dimension
>From: "Swidan, Firas" <swidanf at janelia.hhmi.org>
>To: "r-help at stat.math.ethz.ch" <r-help at
stat.math.ethz.ch>
>Subject: [R] Indexing issue
>Date: Tue, 01 Aug 2006 15:57:01 -0400
>
>Hi,
>
>R is having the following weird behavior and I am not sure if that is a
>feature or a bug:
>
>I am working on the following "3D" array:
>
> > bIm
>, , 1
>
> [,1]
>[1,] TRUE
>[2,] TRUE
>[3,] TRUE
>[4,] TRUE
>[5,] TRUE
>
> > class(bIm)
>[1] "array"
> > dim(bIm)
>[1] 5 1 1
>
>When I try to get the first 2D subarray, the whole thing folds into a
>vector:
>
> > bIm[,,1]
>[1] TRUE TRUE TRUE TRUE TRUE
>
>This causes a lot of trouble in the R code as one would have expected to
>get
>a 2D array but ends up with this "logical" vector.
>
>Is this the way it was meant to be? Does not this behavior bother anyone
>else besides me?
>
>Thanks for the help,
>Firas.
>
>______________________________________________
>R-help at stat.math.ethz.ch 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.