saving a regression model to a file
On Apr 14, 2011, at 12:45 PM, Alison Callahan wrote:
Hello all,
First off, I am using R version 2.13.0 in Ubuntu.
I have read previous posts in the R mailing list on saving models for
later use, and the responses indicate using the R save() function to
save a model and then using load() to load it is one way to go.
However, when I use the save() function to save a model to a file, and
then try to load it using load(), the loaded "model" is just an object
of class Character. Here is the relevant R code:
#######creating the model#########
data <- read.table("../synthetic_data_4.csv", header=TRUE, sep=",")
data <- data.frame(data)
data$type <- factor(data$type)
pcrmodel <- pcr(formula=count~week+type+total, data=data, x=TRUE, y=TRUE)
#########getting summary of model########
summary(pcrmodel)
Output:
Data: X dimension: 318 4
Y dimension: 318 1
Fit method: svdpc
Number of components considered: 4
TRAINING: % variance explained
1 comps 2 comps 3 comps 4 comps
X 99.57 100.00 100.00 100.00
count 13.70 16.01 16.17 16.54
########saving the model#########
save(pcrmodel, file='model.rda')
########loading the model#########
model <- load('model.rda')
Your error is above, in that you are assigning the result of load() to a new object and presuming that the new object contains 'pcrmodel'. If you look at ?load, you will see that the function returns a character vector of the names of the objects contained in the file you are loading. Thus, 'model' is a character vector as show below, in this case, likely containing a single entry of "pcrmodel". Type: model at the R prompt.... If you use: summary(pcrmodel) after the load() call, you should get your normal model summary output. When using load(), it restores the saved objects in the file to the current workspace. If you use: ls() you should see 'pcrmodel' listed, along with anything else in your current workspace. HTH, Marc Schwartz
########getting summary of model after loading###########
summary(model)
Output:
Length Class Mode
1 character character
##################################
What am I doing wrong? Or is this not the correct way to save a model
to be used later? Thanks,
Alison