title: Splitting a Dataframe column on Delimiter and retaining all other columns
body: <p>I have the "raw_input" dataframe below. If you look at the "Summary" column. There is a 
     <strong>delimiter ':'</strong> that I would like to create two additional columns on, and append to the existing dataframe  </p>
  
  <p>I would like to split that "Summary" column into two columns('Work
     Package' and 'Task')</p>
  
  <p>I can split the delimiter using command below. But I don't know how to append/merge it back to the existing dataframe</p>
  
  <pre><code>split_data = pd.DataFrame(raw_input['Summary'].str.split(':',1).tolist(),columns=['Work Package','Task'])
  
  print(raw_input)
  
           Key                                     Summary       Status                                        Description     Updated
  0  XTBOW-310  Data Mgmt: Product Assesment and Selection  In Analysis  - To establish a provider for the solution of ...  2017-05-26
  1  XTBOW-420       Data Mgmt: Vendor &gt; CIBC Implemention          NaN  - Integrate with Vendor to fetch Corporate Act...  2017-05-19
  2  XTBOW-421             Trade Migration: PVs and Greeks          NaN  - PVs and Greeks regression gap analysis betwe...  2017-05-19
  3  XTBOW-422       Trade Migration: Reports (XTC vs XT2)          NaN                                                NaN  2017-05-19
  
  
  
  print(split_data)
  
        Work Package                              Task
  0        Data Mgmt   Product Assesment and Selection
  1        Data Mgmt        Vendor &gt; CIBC Implemention
  2  Trade Migration                    PVs and Greeks
  3  Trade Migration              Reports (XTC vs XT2)
  </code></pre>