title: String to time python in hours and minutes and calculate difference
body: <p>I am taking time as input from the user in the <code>HH:MM</code> format. Let's say 00:00 and now I want to keep adding a minute to the time and make it 00:01, 00:02 and so on.</p>
  
  <p>Also, I am taking two inputs form the user <code>start_time</code> and <code>end_time</code> as strings. How can I calculate the difference between the two times as well in minutes?</p>
  
  <p>I am new to Python and any help would be appreciated!</p>
  
  <p>I am using the below code:</p>
  
  <pre><code>#to calculate difference in time
  time_diff = datetime.strptime(end_time, '%H:%M') - datetime.strptime(start_time, '%H:%M')
  minutes = int(time_diff.total_seconds()/60)
  print minutes
  
  #to convert string to time format HH:MM
  start_time = datetime.strptime(start_time, '%H:%M').time()
  
  #to increment time by 1 minute
  start_time = start_time + datetime.timedelta(minutes=1)
  </code></pre>
  
  <p>I am not able to increment the <code>start_time</code> using timedelta.</p>