title: Pandas selection by MultiIndex
body: <p>Question about selecting rows by MultiIndex.</p>
  
  <p>df:</p>
  
  <pre><code>              colA   ColB
  
     A1   B1   1  ca1  cb1
               2  ca2  cb2
          B2   1  ca3  cb3
               2  ca4  cb4 
     A2   B1   1  ca5  cb5
               2  ca6  cb6
          B2   1  ca7  cb7
               2  ca8  cb8
  </code></pre>
  
  <p>I want to select colA from A2/B1 where MultiIndex levels(2) > 1.
  I'm doing it in multiple steps:</p>
  
  <pre><code>df1=df.loc[A2,[B7],:,]  
  </code></pre>
  
  <p>for some reason I have to present level(1) in brackets</p>
  
  <pre><code>df1.index = x1.index.droplevel(0)
  
  df1.index = x1.index.droplevel(0)
  
  df1.loc[1:,'colA']
  </code></pre>
  
  <p>I know it is way too much but I cant figure how to do it simpler. Ways I can think of don't want to work.</p>