title: Partial Plot can't be produced from randomForest in R
body: <p>The model is constructed and all the variable importance plots can be produced. However, when I used <code>partialPlot</code> on continuous variable, for example <code>purchase_value</code>:
  <code>partialPlot(rf, fraud_data_train, purchase_value, which.class = 1)</code>
  the error is</p>
  
  <pre><code>Error in is.finite(x): default method not implemented for type 'list'
  </code></pre>
  
  <p>For the categorical variable(<code>browser</code>) the error is 
  <code>partialPlot(rf, fraud_data_train, browser, which.class = 1)</code></p>
  
  <pre><code>Error in FUN(X[[i]], ...) : 
    only defined on a data frame with all numeric variables
  </code></pre>
  
  <p>The data is available <a href="https://www.dropbox.com/s/o7f91fb9hs1cchl/data.rda?dl=0" rel="noreferrer">here</a> and the code is as below:</p>
  
  <pre><code>rf = randomForest(y = fraud_data_train$class_factor, 
                    x = fraud_data_train[,-predictors_notinclude],
                    ntree = 30, mtry = 4, keep.forest = TRUE,
                    importance = TRUE, proximity = TRUE)
  partialPlot(rf, fraud_data_train, purchase_value, which.class =1)
  </code></pre>
  
  <p><strong>Update:</strong></p>
  
  <p>Here is the screenshot from my R studio console:
  <a href="https://i.stack.imgur.com/YsKaA.png" rel="noreferrer"><img src="https://i.stack.imgur.com/YsKaA.png" alt="enter image description here"></a></p>
  
  <p><strong>Update 2</strong></p>
  
  <p>Somehow the plot showed up in the notebook markdown..but still confused why it can't be output in the console
  <a href="https://i.stack.imgur.com/yujSS.png" rel="noreferrer"><img src="https://i.stack.imgur.com/yujSS.png" alt="enter image description here"></a></p>