title: R: Calculating mean() from a list
body: <p>I have cut of a frame from a data.set. 
  <img src="https://i.stack.imgur.com/C1zRa.jpg" alt="picture"></p>
  
  <p>The problem is, that I can not calculate the mean Value of Var1, as it is probably not numeric.</p>
  
  <p>How do I proceed?</p>
  
  <pre><code>mean(c1[, "Var1"])
  mean(c1$Var1)
  </code></pre>
  
  <p>Doesn't work...</p>
  
  <pre><code>&gt; c1["Var1"]
          Var1
  116   661574
  128   671194
  331   847073
  454   933425
  652  1113353
  761  1220950
  764  1223786
  978  1580029
  1150 1987981
  1367 2900735
  1380 2976310
  1383 3002309
  1404 3149761
  1408 3178648
  1439 3431430
  1488 3754229
  1506 3910297
  &gt; mean(c1[, "Var1"])
  [1] NA
  </code></pre>