title: how to do permuation between values of 2 columns in pandas
body: <p>let s say I have a dataframe containing  tennis matches each match contains the name of the player 1 and the player 2</p>
  <pre><code>di={'player1':[&quot;adam&quot;,&quot;luke&quot;,&quot;roy&quot;], 'player2': [&quot;james&quot;,&quot;steve&quot;,&quot;derek&quot;]}
  df=pd.DataFrame(data=di)
  df
  </code></pre>
  <blockquote>
  <p>so I have something like this</p>
  </blockquote>
  <pre><code>player1   player2
  0    adam   james
  1    luke   steve
  2     roy   derek
  </code></pre>
  <blockquote>
  <p>I want to Randomly do a permutation between the 2 columns which something completely fine because the columns describe the same entity in the same context and have something like this</p>
  </blockquote>
  <pre><code>  player1 player2
  0   james   adam 
  1   steve    luke
  2     roy   derek
  </code></pre>