title: Adding secondary y axis to bar line chart in ploty express
body: <p>I have a simple bar line chart. How can I add a secondary y-axis so I could show line chart (Column1) in a more representative way.</p>
  <p>This is the code:</p>
  <pre><code>import pandas as pd
  import dash
  import plotly.express as px
  
  data = [['A',100,880],['B ',50,450],['C',25,1200]]
  df = pd.DataFrame(data,columns=['Letter','Column1','Column2'])
  fig = px.line(x=df['Letter'], y=df['Column1'], color=px.Constant(&quot;Column1&quot;),
               labels=dict(x=&quot;Letter&quot;, y=&quot;Column2&quot;, color=&quot;Legend&quot;))
  fig.add_bar(x=df['Letter'], y=df['Column2'], name=&quot;Letter&quot;)
  fig.show()
  </code></pre>
  <p><a href="https://i.stack.imgur.com/ut7to.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ut7to.png" alt=" " /></a></p>
  <p>Thanks in advance!</p>