title: rcorr() function for correlations
body: <p>I´m building a correlation between two different matrices with <code>rcorr()</code> function in R:</p>
  
  <pre><code>res &lt;- rcorr(as.matrix(table1), as.matrix(table2),type="pearson")
  </code></pre>
  
  <p>It seems to be working fine, however I want to avoid within table correlations - any suggestion?</p>