title: Ordering bars in barplot()
body: <p>I have a dataframe, and one of the variables (let's call it Q1) has several levels: "No use", "30 min", "1 hour", "2 hours", "3+ hours".</p>
  
  <p>How can I plot a barplot(), where the bars are in the order of factor levels? I tried using sort(), but that doesn't do the trick.</p>
  
  <p>EDIT: As requested, some sample data:</p>
  
  <pre><code>Q1
  1 hour
  1 hour
  30 min
  2 hours
  3+ hours
  3+ hours
  3+ hours
  3+ hours
  2 hours
  1 hour
  2 hours
  1 hour
  30 min
  </code></pre>
  
  <p>I've tried:</p>
  
  <pre><code>barplot(table(sort(Q1)), main = "Q1 Answer Distribution", ylim = c(0, 250), cex.axis=0.9)
  </code></pre>
  
  <p>but it doesn't give me what I need.</p>