Hello,
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:
[1] C
attached base packages:
[1] stats graphics grDevices utils datasets methods base
loaded via a namespace (and not attached):
[1] compiler_3.6.2 tools_3.6.2
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