title: Difficulties with simple ggplot histogram
body: <p>I'm an absolute beginner at R, so please excuse the simplicity of this question. I'm having trouble loading a file in R and making a histogram plot from a column of data. Here's my code:</p>
  
  <pre><code>library('ggplot2')
  df &lt;- read.csv('/PATH/TO/FILE', sep=' ', head=FALSE)
  vals &lt;- df[,2]
  qplot(df, data=vals, geom="histogram")
  
  Error: ggplot2 doesn't know how to deal with data of class numeric
  </code></pre>
  
  <p>Can anyone show me what the problem is? Thanks in advance for the help.</p>