title: Querying pandas against each other
body: <p>I am trying to filter a df against another, something like this:</p>
  
  <pre><code>df1:
       myval
  0    1.2
  1    3.5
  2    5.7
  3    0.4
  
  df2:
       thrsh
  0    0.4
  1    5.5
  2    1.0
  3    0.0
  </code></pre>
  
  <p>I would love to query this way:</p>
  
  <pre><code>(df1['myval']&gt;df2['thrsh'])
  </code></pre>
  
  <p>so to come out with a new df which would have all the combinations:</p>
  
  <p>df3:</p>
  
  <pre><code>thrsh  myval 
  0      0    true
         1    true
         2    true
         3    false
  1      0    false
         1    false
         2    true
         3    false
  </code></pre>
  
  <p>basically creating a 3rd dimension out of the combination of the 2 dfs.
  as for now the result is "ValueError: Can only compare identically-labeled Series objects".</p>
  
  <p>any idea? 
  thank you so much!</p>