title: Convert factor containing AM/PM to 24 hours HH:MM time format using R programming
body: <p>I use R.</p>
  
  <p>It should not be a difficult thing at all. All I am missing is the sintax I guess.
  I have a data frame named 'twyrs' and in that one column is a time column. 
  when I do  class(twyrs$TIME) it's showing 'factor'.
  The time is in the format "9:00 PM","00:15 AM" and so on.  </p>
  
  <p>All i need is the time to be in the format "21:00" and "00:15" format respectively. That is 24 hours HH MM format. I dont have any seconds attached to my time. Only Hours and mins.</p>
  
  <p>I have tried </p>
  
  <p>library(chron)<br>
  x &lt;- chron(times=twyrs$TIME)</p>
  
  <p>Any help?</p>