How to avoid NA columns in dcast() output?

Question

How can I avoid NA columns in dcast() output from the reshape2 package?

In this dummy example the dcast() o

Answer 1

You could rename the NA column of the output and then make it NULL. (This works for me).

require(reshape2)
data(iris)
iris[ , "Species2"] <- iris[ , "Species"]
iris[ 2:7, "Species2"] <- NA

(x <- dcast(iris, Species ~ Species2, value.var = "Sepal.Width", 
            fun.aggregate = length)) 

setnames(x , c("setosa", "versicolor", "virginica", "newname"))

x$newname <- NULL