title: ggplot geom_bar is plotting counts rather than values, even with stat="identity" setting enabled
body: <p>I am using ggplot in python and just trying to make a basic bar chart. For reasons I don't understand, the bar heights are corresponding to counts of variable names, rather than the actual variables.</p>
  
  <p>Simple example</p>
  
  <pre><code>pattern = pd.Series(['standard', 'woolly', 'brown', 'spotted', 'red', 'wheat', 'grey'], dtype = 'category')
  population = pd.Series([12, 2, 7, 3, 2, 4,5])
  patternCount = pd.DataFrame({'color':pattern, 'population':population})
  
  ggplot(aes(x = 'attribute', y = 'population'), data = animalCounts) +\
  geom_bar(stat = "identity")
  </code></pre>
  
  <p>Gives me a bar chart that looks like this.
  <a href="https://i.stack.imgur.com/AvDVF.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/AvDVF.png" alt="Barplot that shows counts rather than values"></a></p>
  
  <p>I know these are counts, rather than just the number one, since if I have duplicate of any of these names, that variable shows as "2".</p>
  
  <p>I presume I am making some really simple mistake here.  Thanks for any help.</p>
  
  <p>Edit: As per Ron Norris's request, here is the same figure, but scaled to 12, rather than 1.</p>
  
  <p><a href="https://i.stack.imgur.com/vUxW0.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/vUxW0.png" alt="as above but scaled differently"></a></p>