title: r: replace_na() not replacing NAs
body: <p>I have a variable with NAs called <code>df$salesContribution</code>.</p>
  
  <p>Using <code>dplyr</code> I've created a statement below, but can't figure out why my <code>df$salesContribution</code> is returning NAs still:</p>
  
  <pre><code>df&lt;- df %&gt;% 
    mutate(salesContribution = as.numeric(salesContribution)) %&gt;% 
    replace_na(0)
  </code></pre>
  
  <p>Is the <code>0</code> not registering? </p>