[R] Does SQL group by have a heavy duty equivalent in R

[hadley wickham]

> I converted the whole data frame to character by using
> as.matrix

You shouldn't need to do that.

> And then using a posting that explained how to get the naming conventions
> back (which had been lost when converting to matrix)
>
> Anything that I did not list with the id's it insisted in including them
> with the measured variables. In other words it would not let me drop.
>
> despite
>
> melted<-melt(BigDF, id=c("SAMPLE_ID","ASSAY_ID"),
> measured=c("GENOTYPE_ID","DESCRIPTION"))

That should be measure=c(...)

Hadley