title: Why this error happen "duplicated name in data frame using '.'?
body: <p>I have a data frame with 30 row and 850 column(features). 
  when I want to use svm or other classifier with caret and e1071 packages, I faced this error!</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>Error in terms.formula(formula, data = data) : 
    duplicated name 'X10Percentile' in data frame using '.'</code></pre>
  </div>
  </div>
  
  Even when I want to use feature selection method such as <strong>Boruta</strong>, I face the same error.
  I double check my feature and found nothing.  I thought I must have the same column name in data frame so I create a sample data and check as follow:</p>
  
  <pre><code>test&lt;-data.frame("w1"=c(1:6),"w1.1"=c(2:7),"w1"=c(3:8), "ta"=c("T","F","T","F","F","T"))
  
  set.seed(100)
  train &lt;- createDataPartition(y=test$ta,p=0.6,list = FALSE)
  TrainSet &lt;- test[train,]
  TestSet &lt;- test[-train,]
  
  trcontrol_rcv&lt;- trainControl(method="cv", number=10) 
  
   svm_test&lt;-svm(ta ~., data=TrainSet,trControl=trcontrol_rcv)
  </code></pre>
  
  <p><strong>It works good and no Error occurs.</strong>
  As I see no error happen when test data even has exactly the same colname.
  I want to know why this error"Error in terms.formula(formula, data = data) : 
    duplicated name 'X10Percentile' in data frame using '.'" happen for my data, and how can I eliminate  it?
  Thank you in advance.</p>