title: converting year to year-month-day python pandas csv
body: <p>Please I have close to 10 entries in a csv file as follow</p>
  
  <pre><code>PatienceID      Case        Treatment     Admitted_Date      Discharged_Date
  PAT1002         Fever        Yes           1929-02-10         1929-02-13
  PAT1023         Ebola        Yes           2015-10-21         2015-12-29
  PAT1003         HIV          No            2012               2014-02-21
  PAT1991         Headache     Yes           2013               2013
  PAT2028         Epilepsy     Yes           2011               2016
  PAT2931         Malaria      Yes           2016-01-23         2016
  </code></pre>
  
  <p>Please if we study the csv, there are values under <code>Admitted_Date</code> and/or <code>Discharged_Date</code> which only have a year without <strong>Month-Day</strong>. I don't know how to complete date with Month-DAY (I.e so that <code>Discharge_Date</code> will precede the admitted e.g. let's consider <code>Admitted_Date = 2013</code> and <code>Discharged_Date = 2013</code>, if <code>Admitted_Date</code> has <code>01-01-2013</code> then the <code>Discharged_Date</code> should have <code>12-12-2013</code> (January to December)</p>
  
  <p>I have tried out possibilities but it gets messier. I appreciate, thank so much.</p>
  
  <p><strong>Expected output:</strong> </p>
  
  <pre><code>PatienceID      Case        Treatment     Admitted_Date      Discharged_Date
      PAT1002         Fever        Yes        1929-02-10         1929-02-13
      PAT1023         Ebola        Yes        2015-10-21         2015-12-29
      PAT1003         HIV          No         2012-MM-DD       2014-02-21
      PAT1991         Headache     Yes        2013-MM-DD         2013-MM-DD
      PAT2028         Epilepsy     Yes        2011-MM-DD         2016-MM-DD
      PAT2931         Malaria      Yes        2016-01-23         2016-MM-DD
  </code></pre>
  
  <p><strong>What I have tried so far</strong> </p>
  
  <pre><code>import pandas as pd
  
  DF = pd.read_csv('mydata.csv') 
  for Admitted_Date, Discharged_Date in DF
    pd.to_datetime(mydata.pop('Date'), format="%b%Y")
  </code></pre>