title: How to combine 2 dataframes on a condition?
body: <p>I have 2 dataframes.</p>
  <p>df1 -</p>
  <pre><code>     T1    T2    T3    T4
  ID1  0     1.3   -1.5   0
  ID2  0.05  0.3    0    -0.004
  </code></pre>
  <p>df2 -</p>
  <pre><code>     Value1    Value2    Value3    Value4    
  T1   0         0         1          0    
  T2   0         1         0          0 
  T3   1         0         0          1 
  T4   0         1         1          1 
  </code></pre>
  <p>Now, I want the following result:</p>
  <pre><code>     Value1    Value2    Value3    Value4 
  ID1  1          1         0         1
  ID2  0          2         2         1 
  </code></pre>
  <p>In the final result, I want to merge df1 and df2.</p>
  <p>For example,
  In df1, ID1 row we have first value zero so we will ignore T1 in df2. We will skip to next value 1.3 in d1 and since this value is not equal to zero, we will take the T2 values frm df2 and put it in output table. Similarly for every cell.</p>