title: Python replacing partial string in a dataframe column
body: <p>I have a dataframe similar to the following: -</p>
  
  <pre><code>df = pd.DataFrame(data={'Date':['12/05/2014', '12/05.2015', '12/05//2016'], 'Day':['Monday','Tuesday','Thursday']})
  
            Date       Day
  0   12/05/2014    Monday
  1   12/05.2015   Tuesday
  2  12/05//2016  Thursday
  </code></pre>
  
  <p>I want to clean the <strong>Date</strong> column where some dates are not in proper format. The dates are in string format which I will convert to date format after cleaning.</p>
  
  <p>I found some help from other stackoverfolw posts and tried the following: -</p>
  
  <pre><code>1. Loop method
  
     for idx, row in df.iterrows():
         if '.' in df.loc[idx,'Date']:
             df.loc[idx,'Date'].replace('.','/')
  
  2. Regex method
  
     df.Date.replace({'.','/'}, regex=True)
  </code></pre>
  
  <p>None of the above methods return the dates in desired format and return the dataframe unchanged. Is there another method which works?</p>
  
  <p>Also, is there a method by which it is possible to replace in one command both kinds of strings ('.' and '//') with the correct string ('/')?</p>