converting numeric to ordered
On Fri, 14 Sep 2001, Duncan Mackay wrote:
Hello all, would someone please tell me why the following code doesn't "work" (i.e. do what i expected!). I wanted to convert numeric variables in a matrix to ordered (for input as nominal variables into the 'daisy' program). Why does the following code seem to work, but the "is.ordered" command reports that the variables are not ordered (factors)??
It's a matrix. "ordered" is a class. Only data frames can have columns of different classes. I think you want
xxx <- as.data.frame(xxx) xxx
V1 V2 V3
1 0 1 0
2 1 0 1
3 0 1 0
xxx[] <- lapply(xxx, as.ordered)
When ?daisy says
x: data matrix or dataframe. Dissimilarities will be computed
between the rows of `x'. Columns of mode `numeric' will be
recognized as interval scaled variables, columns of class
`factor' will be recognized as nominal variables, and columns
of class `ordered' will be recognized as ordinal variables.
the comment applies to data frames only. (Martin: might you clarify
this?)
xxx <- matrix(c(0,1,0,1,0,1,0,1,0),ncol=3) xxx
[,1] [,2] [,3] [1,] 0 1 0 [2,] 1 0 1 [3,] 0 1 0
yyy <- apply(xxx,2,as.ordered) yyy
[,1] [,2] [,3] [1,] 1 2 1 [2,] 2 1 2 [3,] 1 2 1
apply(yyy,2,is.ordered)
[1] FALSE FALSE FALSE Duncan ******************************************* Dr. Duncan Mackay Biology Flinders University GPO Box 2100 Adelaide S.A. 5001 AUSTRALIA Ph (08) 8201 2627 FAX (08) 8201 3015 http://www.bio.flinders.edu.au/dam/damres.htm -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
Brian D. Ripley, ripley at stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272860 (secr) Oxford OX1 3TG, UK Fax: +44 1865 272595 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._