title: Overlay bar and line plots using ggpubr
body: <p>I am trying to make a overlaid plot, having 2 y-axes. I want one plot to be a bar plot, the other to be a line plot. I know how to do this in ggplot2 (i.e. <a href="https://stackoverflow.com/questions/37094586/ggplot2-overlay-of-barplot-and-line-plot">ggplot2 overlay of barplot and line plot</a>) but I would like to learn how to do this using the <code>ggpubr</code> package. I'd be grateful for any insight anyone can provide! <strong>I know is is an elementary question, so thank you for bearing with me!</strong></p>
  <p>In the interest of clarity, I have included the sample data frame provided by @SpencerTrinh in the linked question.</p>
  <pre><code># Sample data
  df1 &lt;- data.frame(frax = c(16,30,60,64), solvb = c(0,0,100,100))
  df2 &lt;- data.frame(type = factor(c(&quot;mascot&quot;,&quot;mstat&quot;), levels = c(&quot;mascot&quot;,&quot;mstat&quot;)), 
                   frax = c(30,35,40,45,50,55), phos = c(542,413,233,500,600,650))
  </code></pre>
  <p>This is what I'm looking for:
  <a href="https://i.stack.imgur.com/8i78J.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/8i78J.png" alt="enter image description here" /></a></p>