On 9/9/2010 10:54 AM, William Dunlap wrote:
-----Original Message----- From: r-devel-boun...@r-project.org [mailto:r-devel-boun...@r-project.org] On Behalf Of Arni Magnusson Sent: Wednesday, September 08, 2010 11:55 AM To: r-devel@r-project.org Cc: Simon Urbanek Subject: [Rd] Drop single-dimensional arrayHi Simon, thank you for the concise reply. Do you mean the reported behavior of drop() is not a bug? It looks like a borderline bug to me (see below), but I'm not the judge of that. If this is the intended behavior and serves an actual purpose, then that could be explicitly documented in a \note{} on the help page. Such a note would slightly reduce the surprise of users running into this behavior. This is related to the oddity that one-dimensional arrays are: array(month.abb, dim=c(1,1,12)) # array array(month.abb, dim=c(1,12)) # matrix array(month.abb, dim=12) # array Firstly, one would expect the pattern to be array-matrix-vector.I would expect the array() constructor function to return something of class array. (I guess matrix is acceptable because it inherits from array). One dimensional arrays and vectors act very similarly when used in R code. E.g., names(array1d) gives you the same thing as dimnames(array1d)[[1]]. Accessing them from C code probably shows more differences. Are there features beyond drop's behavior that are causing you to be concerned about differences between the 2 types? drop(x) and x[..., drop=TRUE] have always bugged me because you couldn't control which dimensions got dropped. E.g., if you have a n by 2 by 3 array and want to get the 3rd n by 2 slice of it as a matrix you can do array[,,3,drop=TRUE] except when n==1. It would be nice to be able to say "drop the 3rd dimension, throwing an error if that dimension is not 1".
That always bugged me too. The 'abind' package has an 'adrop()' function with this behavior, and I was just working on an enhancement of it that would make it able to convert 1-d arrays to named vectors when this thread started. -- Tony Plate
Bill Dunlap Spotfire, TIBCO Software wdunlap tibco.com
______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
