title: Number formatting axis labels in ggplot2?
body: <p>I'm plotting a fairly simple chart using ggplot2 0.9.1.</p>
  <pre><code>x &lt;- rnorm(100, mean=100, sd = 1) * 1000000
  y &lt;- rnorm(100, mean=100, sd = 1) * 1000000
  df &lt;- data.frame(x,y)
  
  p.new &lt;- ggplot(df,aes(x,y)) +
    geom_point()
  print(p.new)
  </code></pre>
  <p>Which works, but ggplot2 defaults to scientific notation that is inappropriate for my audience. If I want to change the x-axis label format by entering:</p>
  <pre><code>p.new + scale_x_continuous(labels = comma)
  </code></pre>
  <p>I get:</p>
  <blockquote>
  <p>Error in structure(list(call = match.call(), aesthetics = aesthetics,  :
  object 'comma' not found</p>
  </blockquote>
  <p>What am I doing wrong? I note that the language changed recently from &quot;formatter&quot; to &quot;labels&quot;. Perhaps I'm misreading the man page?</p>
  <p><strong>Edit: I was indeed misreading the man page</strong></p>
  <p>Need to load <code>library(scales)</code> before attempting this.</p>