**From:** Achim Zeileis (*zeileis@ci.tuwien.ac.at*)

**Date:** Sat 03 May 2003 - 05:49:04 EST

**Next message:**Song, Guangchun: "[R] Does R implement Hypergeometric test?"**Previous message:**langensk@fas.harvard.edu: "[R] Creating Dummy Variables with if else phrase"**In reply to:**langensk@fas.harvard.edu: "[R] Creating Dummy Variables with if else phrase"**Next in thread:**Peter Dalgaard BSA: "Re: [R] Creating Dummy Variables with if else phrase"

Message-id: <200305021949.h42Jn43b031320@thorin.ci.tuwien.ac.at>

On Friday 02 May 2003 21:41, langensk@fas.harvard.edu wrote:

*> Dear All,
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*>
*

*> I want to do 52 state dummy variables. In order to make it easier
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*> for me, I thought of using the below commands. (x is the vector with
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*> state variables, matrix will correspond to the dummy variables)
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*>
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*>
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*> x <- c(1,2,NA,4)
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*> matrix <- matrix(0,nrow=4,ncol=4)
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*>
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*> for (i in 1:4) {
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*> if (is.real(x[i])) {
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*> matrix[i,x[i]] <- 1 } else {
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*> matrix[i,] <- rep(NA,4)
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*> }
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*> }
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*>
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*> This gives me the following matrix:
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*>
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*> 1 0 0 0
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*> 0 1 0 0
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*> 0 0 0 0
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*> 0 0 0 1
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*>
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*> But I want it to look as follows:
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*>
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*> 1 0 0 0
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*> 0 1 0 0
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*> NA NA NA NA
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*> 0 0 0 1
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*>
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I don't really understand why you want to create a matrix that way,

but if you want to do it the way described above

is.real(x[i])

seems to be the wrong function (because x is a real vector in the

example above). If you want to test for NA you should use

!is.na(x[i])

instead.

Z

*> I want the forth row to be NA, but it is unchanged, i.e., 0. The
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*> second "else" phrase does not seem to work, and I cannot see what is
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*> wrong.
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*>
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*> I would be very grateful for your help.
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*>
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*> Regards, Sophie
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*>
*

*> ______________________________________________
*

*> R-help@stat.math.ethz.ch mailing list
*

*> https://www.stat.math.ethz.ch/mailman/listinfo/r-help
*

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**Next message:**Song, Guangchun: "[R] Does R implement Hypergeometric test?"**Previous message:**langensk@fas.harvard.edu: "[R] Creating Dummy Variables with if else phrase"**In reply to:**langensk@fas.harvard.edu: "[R] Creating Dummy Variables with if else phrase"**Next in thread:**Peter Dalgaard BSA: "Re: [R] Creating Dummy Variables with if else phrase"

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