Hello everyone,

I have got the same problem, with the same error message.

Using R 2.14.1, plyr 1.7.1, R.Studio 0.94.110, Windows XP

The plyr mailing list does not provide any help until now.

 >require(plyr)

 >c(sample(c(1:100), 50, replace=TRUE))->V1

 >c(rep( 1:5, 10))->f1 #variable to group V1

 >data.frame(cbind(V1, f1))->DF

 >str(DF)

 >ddply(DF$V1, DF$f1, "sd")
 >ddply(.(DF$V1), .(DF$f1), "sd")

/>Error in if (empty(.data)) return(.data) : /
/missing value where TRUE/FALSE needed
/

/Thanks everyone,

/

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