title: Pandas merging 2 DataFrames into one graph
body: <p>I am trying to plot two pandas dataframes. One dataframe needs to be displayed as a line graph and another as a scatter plot on the same graph.</p>
  
  <p>This plots the first dataframe:</p>
  
  <pre><code>line = pd.read_csv('nugt_daily.csv',parse_dates=['Date'])
  line = line.sort_values(by='Date')
  line.set_index('Date',inplace=True)
  line['Close'].plot(figsize=(16, 12))
  </code></pre>
  
  <p>I want to plot the following dataframe on top of the previous graph - but as a scatter plot (rather than a line graph):</p>
  
  <pre><code>points = pandas.read_csv('test_doc.csv')
  points = points.sort_values(by='Date')
  points.set_index('Date',inplace=True)
  points.plot(figsize=(16, 12))
  </code></pre>
  
  <p>How can I achieve this? When I run the two codes one after the other, I see two separate graphs for each dataframe.</p>