title: Plot lines from pandas dataframe
body: <p>I have a pandas dataframe, and I want to plot for each column a line, from the origin to the point (a,b)</p>
  
  <pre><code>df = pd.DataFrame(data=[[1,2], [7,3]], columns=['a', 'b'])
  df.head(10)
  df.plot(kind='line')
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/CrWmY.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/CrWmY.png" alt="Here the plot that I get"></a></p>
  
  <p>But I want 2 lines, one from (0,0) to (1,2) and the second from (0,0) to (7,3).</p>