title: How to change ylim per facet with coord_cartesian in ggplot?
body: <p><a href="https://stackoverflow.com/questions/9505270/r-ggplot2-smooth-on-entire-dataset-while-enforcing-a-ylim-cap">This answer</a> describes how to change the y limits of a plot in ggplot.  Suppose I have a faceted plot with a different ylim for each facet, e.g.</p>
  
  <pre><code>facet_wrap(~some_facet, scales="free_y")
  </code></pre>
  
  <p>How can I change the y limits for each facet differently?</p>