title: How to delete the partial values of column in R
body: <p>I have a data "movesdata" and column as Start_time such as:</p>
  
  <pre><code>Group   Start_time                      End_time
  walking 2016-10-10T12:02:54+02:00   2016-10-10T12:06:18+02:00
  walking 2016-10-10T12:06:19+02:00   2016-10-10T12:16:47+02:00
  walking 2016-10-10T12:16:55+02:00   2016-10-10T12:17:14+02:00
  </code></pre>
  
  <p>I want to separate the values of columns Start_time and End_time "2016-10-10T12:02:54+02:00" to just time 12:02:54. I want other values to be removed, but I can not figure it out how? The problem is date changes after 3-4 rows but addition of GMT (+02:00) is constant. I don't want both the date (2016-10-10T) and GMT (+02:00) can anyone help me?</p>