title: Pandas drop duplicate base on 2 columns, having differents value
body: <p>How to drop duplicate in that specific way:</p>
  <pre><code>Index B C
  1     2 1
  2     2 0
  3     3 1
  4     3 1
  5     4 0
  6     4 0 
  7     4 0
  8     5 1
  9     5 0
  10    5 1
  </code></pre>
  <p>Desired output :</p>
  <pre><code>Index B C
  3     3 1
  5     4 0
  </code></pre>
  <p>So dropping duplicate on B but if C is the same on all row and keep one sample/record.</p>
  <p>For example, B = 3 for index 3/4 but since C = 1 for both, I do not destroy them all</p>
  <p>But for example B = 5 for index 8/9/10 since C = 1 or 0, it get destroy.</p>