title: How to remove all characters after the n first in a string dataframe column?
body: <p>Let's take this simple dataframe :</p>
  
  <pre><code>df = pd.DataFrame(dict(Name=['abc','d',np.nan,'vbnc'],NoMatter=[0,6,2,3]))
     Name  NoMatter
  0   abc         0
  1     d         6
  2   NaN         2
  3  vbnc         3
  </code></pre>
  
  <p>I would like to remove in column Name all characters of the strings after the first two ones.</p>
  
  <p>Expected output :</p>
  
  <pre><code>  Name  NoMatter
  0   ab         0
  1    d         6
  2  NaN         2
  3   vb         3
  </code></pre>
  
  <p>How please could I do ?</p>