[Rd] strange bahaviour of predict.lm
ru|pb@rr@d@@ @end|ng |rom @@po@pt
Tue Mar 17 16:32:03 CET 2020
I'm glad that it worked.
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Às 07:10 de 17/03/20, Moshe Olshansky escreveu:
> It works, thank you!
> On Tuesday, 17 March 2020, 5:47:05 pm AEDT, Rui Barradas
> <ruipbarradas using sapo.pt> wrote:
> The problem seems to be that A is a matrix. The following solves the error.
> # create A and b as in your code then run
> A <- as.data.frame(A)
> df1 <- cbind(A, b)
> reg <- lm(b ~ ., df1)
> # etc
> Hope this helps,
> Rui Barradas
> Às 04:36 de 17/03/20, Moshe Olshansky via R-devel escreveu:
> > Hello,
> > Below is my code:
> >> A <- matrix(rnorm(10*3),ncol=3)
> >> b <- runif(10)
> >> reg <- lm(b ~ A)
> >> A1 <- matrix(rnorm(5*3),ncol=3)
> >> A1 <- as.data.frame(A1)
> >> b1 <- predict(reg,A1)
> > Warning message:
> > 'newdata' had 5 rows but variables found have 10 rows
> > And instead of being an array of length 5, b1 is of length 10 and
> is identical to reg$fitted.values
> > I think that it should not be like this.
> > Let me note that for lm I do not care about this as much since I can
> use reg$coefficients, but unfortunately this behaviour is "inherited" by
> other methods. When I am trying to fit a regression tree, predicting
> from the object without using 'predict' method is less trivial.
> > Thank you,Moshe.
> > P.S. just in case:> sessionInfo()
> > R version 3.6.2 (2019-12-12)
> > Platform: x86_64-pc-linux-gnu (64-bit)
> > Running under: Linux Mint 19.1
> > Matrix products: default
> > BLAS: /usr/lib/x86_64-linux-gnu/blas/libblas.so.3.7.1
> > LAPACK: /usr/lib/x86_64-linux-gnu/lapack/liblapack.so.3.7.1
> > locale:
> >  C
> > attached base packages:
> >  stats graphics grDevices utils datasets methods base
> > loaded via a namespace (and not attached):
> >  compiler_3.6.2 tools_3.6.2
> > [[alternative HTML version deleted]]
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