Re: [Gretl-devel] refinement to export to R

On Wed, 13 Sep 2017, Riccardo (Jack) Lucchetti wrote: > I was thinking that we might want to map what we call "discrete" series > into what R calls "factors". The idea is quite simple, and exemplified in > the script below. My question to the list is: is this a good idea? Is it > worth the coding effort (very small IMO)? > > Comments welcome. > > <hansl> > nulldata 50 > > cont1 = normal() > cont2 = normal() > disc1 = floor(uniform(1,5)) > disc2 = floor(uniform(4,18)) > > discrete disc1 disc2 > > list D = dataset > loop foreach i D > if !isdiscrete($i) > D -= $i > endif > endloop > > matrix mD = D > mwrite(mD, "discrete.mat", 1) > > foreign language=R --send-data > D <- gretl.loadmat("discrete.mat"); > for (i in D) {gretldata[,i] <- as.factor(gretldata[,i])}; > summary(gretldata); > end foreign > </hansl> Not sure about this, but my initial reaction is that it may be assuming too much about our "discrete" series. In R, isn't a "factor" a variable that (in gretl parlance) has to be "dummified" before use in regression? That is, an arbitrary encoding of a qualitative characteristic? If so, then I think the above is wrong, since a gretl-discrete series could be a perfectly valid (albeit quantized) quantitative variable; for example, years of education or number of bedrooms. But If I'm wrong about what a "factor" is to R, my objection may fall.