[R] change in I(x) ? in R 2.6.0
Patrick Giraudoux
patrick.giraudoux at univ-fcomte.fr
Thu Oct 25 09:07:53 CEST 2007
Dear listers,
I am trying to use an old script which was working well in the previous
R version. It looks like if it no longer works in R.6.0. I have a model
of the form:
glm(nath2$Positif ~ n + yearday + x + y + I(x^2) + I(y^2) + yearday:x +
yearday:y, family = poisson, data = nath2)
and want to get predicts from a data.frame whose column names are:
> names(data1)
[1] "x" "y" "yearday" "n"
x and y are geographical coordinates, yearday is equal to 120 and n
equal 100; they are all numerics:
> sapply(data1,is.numeric)
x y yearday n
TRUE TRUE TRUE TRUE
when I use the function predict:
> z1<-predict(mod1b,newdata=data1,type="response")
Error: variables ‘I(x^2)’, ‘I(y^2)’ were specified with different types
from the fit
Any idea about what goes wrong ?
Patrick
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