[R] model.frame: object is not a matrix [solved]

[Ross Boylan]

The problem was that my formula had 2 "~" in it.  It also had a lot of 
duplicate terms, but by themselves they don't cause trouble.
Ross
On 4/4/2013 5:30 PM, Ross Boylan wrote:
> Over a decade ago there was a problem with model.frame when the 
> variable names were long:
> https://stat.ethz.ch/pipermail/r-help/2002-August/024492.html
>
> I have similar symptoms with R 2.15.3 on Windows 7:
>
> Browse[2]> x <- model.matrix(formula(myform), p$data)
> Error in model.frame.default(object, data, xlev = xlev) (from 
> mice.R#601) :
>   object is not a matrix
>
> My attempt at a work-around did not help:
> Browse[2]> x <- model.matrix(formula(myform), as.matrix(p$data))
> Error in model.frame.default(object, data, xlev = xlev) (from 
> mice.R#601) :
>   'data' must be a data.frame, not a matrix or an array
> Browse[2]> formula(myform)
> ~educ_sg + ethnic_sg + hiv + J10 + A5 + mar_stat + orientation +
>     Born_US ~ educ_sg + ethnic_sg + hiv + J10 + A5 + mar_stat +
>     orientation + Born_US + (DWPAD_ActAvoid + DWPAD_EducConf +
>     DWPAD_PasAvoid + DWPAD_Support) * ethnic_sg * racGayDiscStress +
>     0
>
> Notice there are many three-way interactions, which certainly will 
> produce long column names.
>
> There was a suggestion in the old thread to set width= in aov, for use 
> by deparse, but I'm not using aov and there are no obvious hooks to 
> deparse.  The level names are also long and include spaces, inequality 
> signs, and periods (also "-" if it uses raw numeric values); perhaps 
> that is the culprit.
>
> Any suggestions for how to diagnose or fix?  This is all happening 
> inside a package that is for general use, and so require recoding of 
> variable and level names to something brief is not very attractive. 
> However, changing these within the program might be workable.
>
> Ross Boylan