title: print all numbers greater than 4 in a single column
body: <p>I have a data with some numbers in a column named radon. I want to find all numbers bigger than 4 and count total.</p>
  
  <p>I do this:</p>
  
  <pre><code>for(i in 1:ncol(data))
  {
      if(data$radon[i]&gt;=4)
      {
          data$radon[i]
      }
  }
  </code></pre>
  
  <p>but is not working.
  how can i changed it?</p>