title: How to get all combinations of three columns in a dataframe in pandas python>
body: <p>All possible combinations of three columns</p>
  
  <p>I am not able to do it with itertools.combinations or itertools.permutations.</p>
  
  <p>Input dataframe :</p>
  
  <pre><code>a   b   c
  1   101 1001
  2   102 1002
  3   103 1003
  </code></pre>
  
  <p>Expected dataframe :</p>
  
  <pre><code>a   b   c
  1   101 1001
  1   101 1002
  1   101 1003
  1   102 1001
  1   102 1002
  1   102 1003
  1   103 1001
  1   103 1002
  1   103 1003
  2   101 1001
  2   101 1002
  2   101 1003
  2   102 1001
  2   102 1002
  2   102 1003
  2   103 1001
  2   103 1002
  2   103 1003
  3   101 1001
  3   101 1002
  3   101 1003
  3   102 1001
  3   102 1002
  3   102 1003
  3   103 1001
  3   103 1002
  3   103 1003
  </code></pre>