如何从插入符号中的`finalModel`中选择不同的模型？

Question

在caret中，使用函数best，tolerance等。我可以选择性能较低（tutorial）的不太复杂的模型。

使用tolerance之后，我现在知道，我希望在caret调整的所有模型中使用第3个模型。是否可以提取类似于我如何选择caret_result$finalModel的模型？或者我是否必须采用该模型的超参数并用它们重新拟合模型？

Answer 1

请参阅update.train：

> mod1 <- train(Species ~ ., data = iris, method = "rpart")
> mod1
CART 

150 samples
4 predictor
3 classes: 'setosa', 'versicolor', 'virginica' 

No pre-processing
Resampling: Bootstrapped (25 reps) 
Summary of sample sizes: 150, 150, 150, 150, 150, 150, ... 
Resampling results across tuning parameters:

  cp    Accuracy   Kappa    
0.00  0.9434796  0.9145259
0.44  0.7609620  0.6544837
0.50  0.4731651  0.2350673

Accuracy was used to select the optimal model using  the largest value.
The final value used for the model was cp = 0. 

> update(mod1, param = list(cp = .44))
CART 

150 samples
4 predictor
3 classes: 'setosa', 'versicolor', 'virginica' 

No pre-processing
Resampling: Bootstrapped (25 reps) 
Summary of sample sizes: 150, 150, 150, 150, 150, 150, ... 
Resampling results across tuning parameters:

  cp    Accuracy   Kappa    
0.00  0.9434796  0.9145259
0.44  0.7609620  0.6544837
0.50  0.4731651  0.2350673

The tuning parameter was set manually.
The final value used for the model was cp = 0.44.