title: Adding two columns in Python
body: <p>I am trying to add two columns and create a new one. This new column should become the first column in the dataframe or the output csv file. </p>
  
  <pre><code>column_1 column_2
  84       test
  65       test
  </code></pre>
  
  <p>Output should be </p>
  
  <pre><code>column         column_1 column_2
  trial_84_test   84      test
  trial_65_test   65      test
  </code></pre>
  
  <p>I tried below given methods but they did not work:</p>
  
  <pre><code>sum = str(data['column_1']) + data['column_2']
  
  data['column']=data.apply(lambda x:'%s_%s_%s' % ('trial' + data['column_1'] + data['column_2']),axis=1)
  </code></pre>
  
  <p>Help is surely appreciated. </p>