title: NAs introduits lors de la conversion automatique
body: <p>I'm presently learning R and I'm suppose to do a knn model on my dataset </p>
  
  <p><a href="https://i.stack.imgur.com/lqmsw.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/lqmsw.png" alt="enter image description here"></a></p>
  
  <p>I've tested this but that doesn't work at all. </p>
  
  <pre><code> predKNN = knn(app[,1:19], test[,1:19],test[,20], k = 3)
  </code></pre>
  
  <p>I get the following error</p>
  
  <pre><code>NAs introduced during the automatic conversion
  </code></pre>