title: stop printing na in plot
body: <p>I am plotting a categorical variable. There is no <code>NA</code> but the plot is coming up with <code>NA</code> bar with no observation in it. How do I stop prinint this <code>NA</code> ber in my plot?</p>
  
  <pre><code>ggplot(data.frame(cat.hour), 
         aes(x=factor(cat.hour, levels=c("1 min","2 min","3 min","4 min","5 min","6 min","7 min","8 min","9 min","10 min")))) + 
    geom_bar(fill="lightgreen")
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/PqL36.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/PqL36.png" alt="enter image description here"></a></p>