title: change timestamp format pandas
body: <p><a href="https://i.stack.imgur.com/RcFOI.png" rel="nofollow noreferrer">Example data</a>How to change the timestamp format which has the format of '2019-12-16-12-40-53' and I want it to convert to '2019-12-16 12:40:53'</p>
  <p>I tried</p>
  <pre><code>    df['timeStamp'] = df['timeStamp'].apply(lambda x: 
                                  dt.datetime.strptime(x,'%Y%b%d:%H:%M:%S'))
  </code></pre>
  <p>and I got the error</p>
  <pre><code>    ValueError: time data '2019-12-16-12-40-53' does not match format '%Y%b%d:%H:%M:%S'
  </code></pre>
  <p>I am attaching an image of data that I am using as timestamp.</p>