title: Sum only numeric columns in pandas
body: <p>I have a df like below, (initial 2 rows are text and 1st column is date)</p>
  
  <pre><code>In [4]: df
  Out[4]: 
             test          bs         dv         if          ir         md         qb         sy          tb
  0       TESTacc      a10900     a10900     a10900    IJJMKK11     a10900     a10900     a10900      a10900
  1   01-Feb-2019  18.8668013  4.6021207  0.9330807  13.9766832  2.9002571  0.2824343  0.8280988   0.8587644
  2   04-Feb-2019   16.187526  3.1000162  0.4145835  14.6465183   2.848472  0.2516608  0.8618771    0.218063
  </code></pre>
  
  <p>I need to get have this csv with 3 decimal precision
  Also I need to add a "Total" Column (rightmost column)
  I have tried the below things, but these are not proper</p>
  
  <p>To add the total column I did:</p>
  
  <pre><code>ndf=df.iloc[2:,1:] #take only numerics in ndf
  ndf = ndf.apply(pd.to_numeric)
  ndf=ndf.round(3)
  df['total']=ndf.sum(axis=1)
  </code></pre>
  
  <p>This is not a proper way of doing simple thing like adding a total column</p>
  
  <p>So I tried
  <code>df=df.apply(pd.to_numeric,errors='ignore')</code>
  but round still wont work on df
  My intent is to just add a Total column and have all numbers rounded to 3 decimals.
  Additional: Once this is done I would add a last row as median row, having median for each column </p>