[R] Problems with data structure when using plsr() from package pls

[Jeff Newmiller]

Using I() in the data.frame seems ill-advised to me. You complain about 96 variables but from reading your explanation that seems to be what your data are. I have no idea whether it makes sense to NOT have 96 variables if that is what your data are. Note that a reproducible example supplied by you might help us guess better,  but it might just be that your expectations are wrong. 
-- 
Sent from my phone. Please excuse my brevity.

On January 13, 2016 11:02:25 AM PST, CG Pettersson <cg.pettersson at lantmannen.com> wrote:
>R version 3.2.3, W7 64bit.
>
>Dear all!
>
>I am trying to make pls-regression using plsr() from package pls, with
>Mevik & Wehrens (2007) as tutorial and the datasets from the package.
>Everything works real nice as long as I use the supplied datasets, but
>I don�t understand how to prepare my own data.
>This is what I have done:
>
>> frame1 <- data.frame(gushVM, I(n96))
>
>Where gushVM is a vector with fifteen reference analysis values of a
>quality problem in grain and n96 is a matrix with fifteen rows and 96
>columns from an electronic nose. I try to copy the methods as in 3.2 in
>Mevik & Wehrens, and want to keep n96 as one variable to avoid
>addressing 96 different variables in the plsr call. If I don�t use I()
>in the call I get 96 variables instead.
>Looking at the dataframe by summary(frame1) get a return quite like
>summary(gasoline) from the package (not shown here).
>But when I try to use plsr() with my own data it doesn�t work due to an
>error in the data structure:
>
>> pls1 <- plsr(gushVM ~ n96, data = frame1)
>Error in model.frame.default(formula = gushVM ~ n96, data = frame1) :
>  invalid type (list) for variable 'n96'
>>
>So, n96 has turned into a list, and that is a problem. If gushVM is a
>vector (one variable) och a matrix (five variables) does not seem to
>change anything, managing n96 is the problem
>I have tried all alternative ways of creating a proper data frame
>suggested in the article with exactly the same result.
>I have tried the documentation for data.frame() but I probably don�t
>understand what it says.
>
>What should I do to change "n96" into something better than "list"?
>
>Thanks
>/CG
>
>Med v�nlig h�lsning/Best regards
>CG Pettersson
>Scientific Project Manager, PhD
>______________________
>Lantm�nnen Corporate R&D
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