$ price                       : int  11200 27000 16000 12750 14500 14900 16000 16250 14250 14250 ...
 $ transmission                : Factor w/ 3 levels "Automatic","Manual",..: 1 1 1 1 1 1 1 2 2 1 ...
 $ mileage                     : int  67068 14827 62794 26676 39554 35309 38538 10401 42668 36099 ...
 $ fuelType                    : Factor w/ 4 levels "Diesel","Electric",..: 1 4 1 1 1 1 1 4 1 1 ...
 $ tax                         : int  125 145 160 145 160 125 125 145 30 20 ...
 $ mpg                         : num  57.6 42.8 51.4 72.4 50.4 60.1 60.1 52.3 62.8 68.9 ...
 $ engineSize                  : num  2 2 3 1.5 3 2 2 1.5 2 2 ...
 $ automaker                   : Factor w/ 4 levels "BMW","Ford","Mercedes",..: 1 1 1 1 1 1 1 1 1 1 ...
 $ age                         : int  8 4 6 5 8 6 5 4 5 6 ...
 $ model_.1.Series             : int  0 0 0 1 0 0 0 0 0 0 ...
 $ model_.2.Series             : int  0 0 0 0 0 0 0 1 0 0 ...
 $ model_.3.Series             : int  0 0 0 0 0 0 0 0 0 0 ...
 $ model_.4.Series             : int  0 0 0 0 0 0 0 0 1 0 ...
 $ model_.5.Series             : int  1 0 1 0 0 1 1 0 0 1 ...
 $ model_.6.Series             : int  0 1 0 0 0 0 0 0 0 0 ...
 $ model_.7.Series             : int  0 0 0 0 1 0 0 0 0 0 ...
 $ model_.8.Series             : int  0 0 0 0 0 0 0 0 0 0 ...
 $ model_.A.Class              : int  0 0 0 0 0 0 0 0 0 0 ...
 $ model_.Auris                : int  0 0 0 0 0 0 0 0 0 0 ...
 $ model_.Avensis              : int  0 0 0 0 0 0 0 0 0 0 ...
 $ model_.Aygo                 : int  0 0 0 0 0 0 0 0 0 0 ...
 $ model_.B-MAX                : int  0 0 0 0 0 0 0 0 0 0 ...
 $ model_.B.Class              : int  0 0 0 0 0 0 0 0 0 0 ...
 $ model_.C-HR                 : int  0 0 0 0 0 0 0 0 0 0 ...
 $ model_.C-MAX                : int  0 0 0 0 0 0 0 0 0 0 ...
 $ model_.C.Class              : int  0 0 0 0 0 0 0 0 0 0 ...

Hello! I used the dummy function to separate the levels of factors of my original variable named "model". Then I am trying to do random forrest prediction.(i have fixed the spaces for the column names using gsub). Then I am setting the training and the testing.

n_rows <- nrow(my_final_cars)
training_idx <- sample(n_rows, n_rows * 0.7)
training_my_final_cars <- my_final_cars[training_idx,]
test_my_final_cars <- my_final_cars[-training_idx,]

But when I try the following I get an error at the train function

my_final_cars_formula <- reformulate(names(training_my_final_cars[, -1]), response = 'price')

ctrl_parameters <- trainControl(method = 'CV', number = 5)

modelLookup('rpart')

my_final_cars_tree <- train(my_final_cars_formula, data = training_my_final_cars, method = "rpart", trControl = ctrl_parameters)


my_final_cars_tree

Error in eval(predvars, data, env) : object 'model_.B' not found

model_.B I am 100% sure that it doesnt exist in my dataset. Do you know why it happens to tell me that it doesnt find a variable that shouldnt be found from the moment that there isnt something named like this in my dataset? Do you have any suggetions?