title: pandas aggregate sum of two columns and make it as one column
body: <p>I am looking for solution to group by and then find the sum of two columns in pandas dataframe and display as one column.</p>
  
  <p>Sum of Net and Gross column for each row and add a new column 'Total' as teh sum of both.</p>
  
  <p>Sample dataset as below</p>
  
  <pre><code>    Name  state    Net  Gross
      A1    TN       100     60
      A2    AP       200     40
      A3    KAR      300     -10 
      A1    TN       10      60
      A2    AP       20      40
      A3    KAR      10     -10 
  </code></pre>
  
  <p>Expected output</p>
  
  <pre><code>    Name  state    Total Amount
      A1    TN       230     
      A2    AP       300     
      A3    KAR      290      
  </code></pre>
  
  <p>I have tried as below in two steps as below</p>
  
  <pre><code>df2 = df1.groupby(['Name', 'State', ]).agg({'Net': 'sum', 'Gross':'sum'})
  df2['Total Amount'] = df2['Net'] + df2['Gross']
  </code></pre>
  
  <p>Is there a way to do this in a single step.Thanks.</p>