title: pandas columns correlation with statistical significance
body: <p>What is the best way, given a pandas dataframe, df, to get the correlation between its columns <code>df.1</code> and <code>df.2</code>? </p>
  
  <p>I do not want the output to count rows with <code>NaN</code>, which <code>pandas</code> built-in correlation does. But I also want it to output a <code>pvalue</code> or a standard error, which the built-in does not.</p>
  
  <p><code>SciPy</code> seems to get caught up by the NaNs, though I believe it does report significance.</p>
  
  <p>Data example:</p>
  
  <pre><code>     1           2
  0    2          NaN
  1    NaN         1
  2    1           2
  3    -4          3
  4    1.3         1
  5    NaN         NaN
  </code></pre>