MATLAB: Elapsed Time for specific month

time

i have dataset as follow 1976/1/30 20:45:48.81 1976/2/2 3:58:35.29 1976/2/3 10:3:31.11 1976/2/3 13:14:40.79 1976/2/6 16:24:49.9 1976/2/16 10:9:0 1976/3/16 10:9:36.8 1976/3/23 3:34:1.2 1976/3/26 5:12:39.4 1976/4/26 11:19:0 1976/4/26 11:19:26.77 1976/5/26 21:50:20 1976/5/2 5:1:14.5 1976/5/3 18:25:0 1976/6/3 18:25:17.25 1976/7/12 23:28:0 1976/7/12 23:28:20.7 1976/7/14 4:10:20 1976/7/19 14:14:8.12 1976/7/20 18:53:1.2 1976/7/22 20:52:0 1976/7/22 20:52:51.92 1976/7/23 15:58:18.92 1976/7/24 17:58:0 1976/8/24 17:58:39.35 1976/8/25 6:33:31.49 i want to group the data monthly.after that i want to find elapsed time of specific month, first time and last time… the data is from 1976 to 2013…

Best Answer

Better in the future to attach a properly-formatted file.
Here's a solution, using a table, datetimes, and splitapply. The result is a duration in units of days:hours: minutes:seconds.
>> dstr = { ...
    '1976/1/30 20:45:48.81'
    '1976/2/2 3:58:35.29'
    '1976/2/3 10:3:31.11'
    '1976/2/3 13:14:40.79'
    '1976/2/6 16:24:49.9'
    '1976/2/16 10:9:0.0'
    '1976/3/16 10:9:36.8'
    '1976/3/23 3:34:1.2'
    '1976/3/26 5:12:39.4'
    '1976/4/26 11:19:0.0'
    '1976/4/26 11:19:26.77'
    '1976/5/26 21:50:20.0'
    '1976/5/2 5:1:14.5'
    '1976/5/3 18:25:0.0'
    '1976/6/3 18:25:17.25'
    '1976/7/12 23:28:0.0'
    '1976/7/12 23:28:20.7'
    '1976/7/14 4:10:20.0'
    '1976/7/19 14:14:8.12'
    '1976/7/20 18:53:1.2'
    '1976/7/22 20:52:0.0'
    '1976/7/22 20:52:51.92'
    '1976/7/23 15:58:18.92'
    '1976/7/24 17:58:0.0'
    '1976/8/24 17:58:39.35'
    '1976/8/25 6:33:31.49'};
>> timestamp = datetime(dstr,'InputFormat','uuuu/M/d H:m:s.SS');
>> timestamp.Format = 'uuuu/MM/dd HH:mm:ss.SS';
>> t = table;
>> [g,t.Year,t.Month] = findgroups(timestamp.Year,timestamp.Month);
>> t.Min = splitapply(@min,timestamp,g);
>> t.Max = splitapply(@max,timestamp,g);
>> t.Elapsed = t.Max - t.Min;
>> t.Elapsed.Format = 'dd:hh:mm:ss'
      Year    Month             Min                       Max                Elapsed   
      ____    _____    ______________________    ______________________    ____________
      1976    1        1976/01/30 20:45:48.81    1976/01/30 20:45:48.81        00:00:00
      1976    2        1976/02/02 03:58:35.29    1976/02/16 10:09:00.00     14:06:10:24
      1976    3        1976/03/16 10:09:36.80    1976/03/26 05:12:39.40     09:19:03:02
      1976    4        1976/04/26 11:19:00.00    1976/04/26 11:19:26.77        00:00:26
      1976    5        1976/05/02 05:01:14.50    1976/05/26 21:50:20.00     24:16:49:05
      1976    6        1976/06/03 18:25:17.25    1976/06/03 18:25:17.25        00:00:00
      1976    7        1976/07/12 23:28:00.00    1976/07/24 17:58:00.00     11:18:30:00
      1976    8        1976/08/24 17:58:39.35    1976/08/25 06:33:31.49        12:34:52
Had to add ".0" to the strings that had no fractional seconds part.
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