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.
Allin