title: Visual correlation between numerical and categorical
body: <p>Is it possible to create a visual correlation map wit numerical and categorical variables?</p>
  
  <p>For example with this values:</p>
  
  <pre><code>val1 &lt;- rep(c(1:2),5)
  val2 &lt;- rep(c('a','b'),5)
  val3 &lt;- paste(val1,val2)
  val4 &lt;- c(1:10)^2
  val5 &lt;- paste('x',val4)
  </code></pre>
  
  <p>Following on the question <a href="https://stackoverflow.com/questions/41053431/how-to-find-the-correlation-between-continuous-and-categorical-variables-in-r">here</a> I can do see the correlation as a table like:</p>
  
  <pre><code>table(val1,val2)
  table(val1,val3)
  etc...
  </code></pre>
  
  <p>This somehow helps, but I'm looking to produce something like a correlation map.</p>
  
  <p>Also, there is a problem as it works between numeric &amp; categorical and categorical &amp; categorical, but it doesn't work with numeric &amp; numeric, like table(val1,val4).</p>
  
  <p>Does anyone has an example of how to achieve a visual correlation representation for mixed numerical &amp; categorical variables?</p>