title: ggplot2 error:Discrete value supplied to continuous scale R
body: <p>I have a dataset called &quot;alldata&quot;, which contains 1000 rows and 2 columns named &quot;day_of_Week&quot; and &quot;label&quot;. The dataset look like this :</p>
  <pre><code>day_of_Week    label
        5        Wday, Clicked
        2        Wday, Clicked
        4        Wday, Clicked
        4        Wday, Clicked
        2        Wday, Clicked
        6        Wday, Clicked
        2        Wday, Clicked
        2        Wday, Clicked
        3        Wday, Clicked
        2        Wday, Clicked
  </code></pre>
  <p>I'm using ggplot2 to plot the data,</p>
  <pre><code>ggplot(alldata, aes(day_of_Week, fill = label)) + geom_density(alpha = 0.2) + xlim(55, 70)
  </code></pre>
  <p>But, I get this error</p>
  <blockquote>
  <p>Error: Discrete value supplied to continuous scale</p>
  </blockquote>
  <p>I have changed the value about xlim or alpha, but I still get the error.
  Do you have any idea what's wrong with this code? where is the error from, and how can I make it work?</p>
  <p>Thank you</p>