[R] getting a variable from an object named using paste
costas at mit.edu
Sat Jul 9 13:01:55 CEST 2005
The subject could be articulated better ;(, but I am stuck...
In any case, my problem is the following: I am trying to use knn, and
it requires a classification. So I am using cmeans for this. What I
want to do is add the classification as a new column in my data.frame
(to be used for knn). Now, the trick is that I would like to name the
output of the cmeans classification based on the number of clusters
(e.g. cmeans30 for 30 clusters). To do this, I do the following:
[The file for this example can be downloaded from:
lala <- read.csv("station-1-120103.txt",header=F)
ll <- cbind(lala$V25,lala$V22)
and sure enough if I type cmeans50 I get the output of this cmeans run.
This also works, naturally:
[and I now get three columns, where the third column is the cluster ID.]
However, when I do what I really want (i.e. not call cmeans50
explicitly, but through the name that I constructed programmatically):
llc <- cbind(ll,(paste("cmeans",num.of.clust,sep=""))$cluster)
I only get two columns (the last term has no effect).
Any ideas as to what I am doing wrong?
Thanks a lot!
Constantinos Antoniou, Ph.D.
Massachusetts Institute of Technology
Intelligent Transportation Systems Program
77 Massachusetts Ave., Rm. 1-249, Cambridge, MA 02139
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