From: Marc Schwartz <MSchwartz_at_mn.rr.com>

Date: Sun 22 Oct 2006 - 02:12:12 GMT

R-help@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. Received on Sun Oct 22 12:16:15 2006

Date: Sun 22 Oct 2006 - 02:12:12 GMT

On Sat, 2006-10-21 at 21:04 -0400, Wensui Liu wrote:

*> Dear Listers,
**>
**> I am wondering how to convert multiple dummy variables to 1 factor variable.
**>
**> Thanks.
**>
*

> wensui

However, I suppose that something along the lines of the following would work.

Level1 Level2 Level3 Level4 Level5 [1,] 0 1 0 0 0 [2,] 1 0 0 0 0 [3,] 0 0 0 1 0 [4,] 0 0 1 0 0 [5,] 0 0 0 0 1

# Create a new factor based upon the index of each 1 in each row # Use the matrix column names as the labels for each level NewFactor <- factor(apply(mat, 1, function(x) which(x == 1)),

labels = colnames(mat))

> NewFactor

[1] Level2 Level1 Level4 Level3 Level5

Levels: Level1 Level2 Level3 Level4 Level5

**HTH,
**
Marc Schwartz

R-help@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. Received on Sun Oct 22 12:16:15 2006

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