[R] using ifelse with surprising results

Steve_Friedman at nps.gov Steve_Friedman at nps.gov
Fri Oct 17 22:50:17 CEST 2008

Thanks for the gracious assistance in advance

I'm working on a non-metric scaling problem and am calculating the distance
for input to isoMDS

Here is the code

vegdata <- tapply(Percent, list(PRIMARY_VE, MASTERID), sum)
x.mat <- matrix(x, nrow=40, ncol=2750, byrow=TRUE, dimnames =
c(dimnames(x)[1], dimnames(x)[2]))

 vegdata.dd <- dist(x)
 vegdata.dd <- ifelse(vegdata.dd==NA, 0.01, x.dd)

Everything works as expected until I try to replace the NA values in the
distance matrix.
the ifelse statement converts the entire dataset to NA.

What am I doing incorrectly?

Once again, Thanks


Steve Friedman Ph. D.
Spatial Statistical Analyst
Everglades and Dry Tortugas National Park
950 N Krome Ave (3rd Floor)
Homestead, Florida 33034

Office (305) 224 - 4282
Steve_Friedman at nps.gov

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