title: Dataframe pandas split str
body: <p>I got a dataframe that contains columns with numbers where some are a single number (1234) and others contains multiple numbers(12340-567-8900)
  I found a way to split the multiple numbers, but if my columns contains single numbers my code fails. </p>
  
  <p>Can anyone point me in the right direction?</p>
  
  <pre><code>    `lens = df['EPDNr'].str.split('-').map(len)
       res = pd.DataFrame({'Title':np.repeat(df['Title'],lens),
                  'Kundenummer':np.repeat(df['Kundenummer'],lens),
                  'Avvikstype':np.repeat(df['Avvikstype'],lens),
                  'Ordrenummer':np.repeat(df['Ordrenummer'],lens),
                  'EPDNr':chainer(df['EPDNr']),
                 'Antall':chainer(df['Antall'])})
  </code></pre>
  
  <p>I want my output to look like
   Column header: EPDNR
  Cell a1 1234
  Cell a2 12340
  Cell a3 567
  cell a4 8900 ect..</p>