[R] Error in 'Contrasts<-' while using GBM.

[Max Kuhn]

Providing a reproducible example and the results of `sessionInfo` will help
get your question answered.

My only guess is that one or more of your predictors are factors and that
the in-sample data (used to build the model during resampling) have
different levels than the holdout samples.

Max

On Sat, Nov 28, 2015 at 10:04 PM, Karteek Pradyumna Bulusu <
kartikpradyumna92 at gmail.com> wrote:

> Hey,
>
> I was trying to implement Stochastic Gradient Boosting in R. Following is
> my code in rstudio:
>
>
>
> library(caret);
>
> library(gbm);
>
> library(plyr);
>
> library(survival);
>
> library(splines);
>
> library(mlbench);
>
> set.seed(35);
>
> stack = read.csv("E:/Semester 3/BDA/PROJECT/Sample_SO.csv", head
> =TRUE,sep=",");
>
> dim(stack); #displaying dimensions of the dataset
>
>
>
> #SPLITTING TRAINING AND TESTING SET
>
> totraining <- createDataPartition(stack$ID, p = .6, list = FALSE);
>
> training <- stack[ totraining,]
>
> test <- stack[-totraining,]
>
>
>
> #PARAMETER SETTING
>
> t_control <- trainControl(method = "cv", number = 10);
>
>
>
>
>
> # GLM
>
> start <- proc.time();
>
>
>
> glm = train(ID ~ ., data = training,
>
>              method = "gbm",
>
>              metric = "ROC",
>
>              trControl = t_control,
>
>              verbose = FALSE)
>
>
>
> When I am compiling last line, I am getting following error:
>
>
>
> Error in `contrasts<-`(`*tmp*`, value = contr.funs[1 + isOF[nn]]) :
>
>   contrasts can be applied only to factors with 2 or more levels
>
>
>
>
>
> Can anyone tell me where I am going wrong and How to rectify it. It’ll be
> greatful.
>
>
>
> Thank you. Looking forward to it.
>
>
>
> Regards,
> Karteek Pradyumna Bulusu.
>
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>
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