title: How to exclude rows by identifying values from two columns?
body: <p>I have two data-frames:</p>
  
  <p>df1:</p>
  
  <pre><code> X1  X2   X3
    1   2  100
    2   3   90
    1   3  100
    3   1  110
    2   1   20
    1   3   30
    2   3   40
    3   1   50
  </code></pre>
  
  <p>df2:</p>
  
  <pre><code> X1  X2   X3  Y
    1   2  100  1
    2   3   90  1
    1   3  100  1
    3   1  110  0
    2   1   20  0
    1   3   30  0
    2   3   40  1
    3   1   50  0
  </code></pre>
  
  <p>I want to exclude rows from df1, for those who have the value 1 in Y column in df2.
  The identifier is (X1, X2).</p>
  
  <p>Expected result:</p>
  
  <pre><code> X1  X2   X3
    3   1  110
    2   1   20
    3   1   50
  </code></pre>