Hello,

I'm trying to use tapply to find group means in a function.  It works
outside of a function, but I get the error message from the following code:
"Error in tapply(index, cluster, mean) : arguments must have same length."
Any suggestions?  Thanks.

eric

d <- data.frame(cbind(cluster=1:2, value1=1:10, value2=11:20))
d

FindClusterTraits <- function(framename, index){
    MeanCluster <- with(framename, tapply(index, cluster, mean))
    return(MeanCluster)
}

d2 <- FindClusterTraits(d, 'value1')

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