CODEWITHSUNDEEP
rgbm
chittip
chittip

Reputation: 31

extract predictor names from varImp

I am using the caret package to run a gbm model. Once the model is run, I use the varImp function to extract the list of important predictors (displays top 20). However I would like to capture the names of the predictors in a character list. How do I do that? The object returned from the varImp does not seem to have the attribute that lists the predictor name - only the variable importance. Here is a sample :

gbmModel= train(target ~. , data = trainData, ....other params )
varimp = varImp(gbmModel, scale=TRUE)
str(varimp)
List of 3
 $ importance:'data.frame': 77 obs. of  1 variable:
..$ Overall: num [1:77] 6.63 0 5.35 2.01 0 ...
$ model     : chr "gbm"
$ calledFrom: chr "varImp"
- attr(*, "class")= chr "varImp.train"
## Display the important variables

varimp

gbm variable importance

 only 20 most important variables shown (out of 77)

           Overall
Var126     100.000
Var189      99.647
Var113      41.994
... And so on

I would like a list like ("Var126", "Var189", "Var113" ...)

Thanks in advance,

Upvotes: 3

Views: 4159

Answers (2)

forever
forever

Reputation: 149

varImp(gbmModel, scale = TRUE)$importance

Return all variables

Upvotes: 1

MrFlick
MrFlick

Reputation: 206308

From the structure of the output you provided, it appears that 

rownames(varimp$importance)

will return the values you are after.

Upvotes: 6

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