Dear Jeff, thanks for the effort, but the use of I() when preparing the dataset is suggested by the authors (Mevik & Wehrens, section 3.2):
+If Z is a matrix, it has to be protected by the ‘protect function’ I() in calls +to data.frame: mydata <- data.frame(..., Z = I(Z)). Otherwise, it will be split into +separate variables for each column, and there will be no variable called Z in the data frame, +so we cannot use Z in the formula. One can also add the matrix to an existing data frame: +R> mydata <- data.frame(...) +R> mydata$Z <- Z In the dataset "gasoline" that is supplied with the pls package, there are two variables; octane and NIR, where NIR is a frame with 401 columns and possible to work with like: plsr(octane ~NIR, data = gasoline) I thought "gasoline" was made like the example above, but I must be missing something else. Whatever I do ends with " invalid type (list) for variable 'n96'" So I am still stuck /CG Från: Jeff Newmiller [mailto:jdnew...@dcn.davis.ca.us] Skickat: den 14 januari 2016 05:16 Till: CG Pettersson; r-help@r-project.org Ämne: Re: [R] Problems with data structure when using plsr() from package pls 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.petters...@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 data frame 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 docum entation 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 Phone: +46 10 556 19 85 Mobile: + 46 70 330 66 85 Email: cg.petters...@lantmannen.com<mailto:cg.petters...@lantmannen.com> Visiting Address: S:t G�ransgatan 160 A Address: Box 30192, SE-104 25 Stockholm Webb: http://www.lantmannen.com<http://www.lantmannen.com/> Registered Office: Stockholm Before printing, think about the environment [[alternative HTML version deleted]] R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
