How do I calculate the duration between two times?

Hi,

I have two different data sets that each contain times in the format 'HH:mm:ss'.

results_start_array (see attached) contains a list of general start times in the first column (each representing the general start time of a participant). Each time indicates when a participant started their task.

results_start_end (see attached) is a cell array of cells, with 12 tables in each cell. Each table has two times. Each of these tables represents a sub-task. In each table, the first row is a start time and the second row is a end time of each respective sub-task.

My goal is to calcualate all the different durations between (for each participant):

• start time of sub-task 1 - general start time
• end time of sub-task 1 - general start time
• start time of sub-task 2 - general start time
• end time of sub-task 2 - general start time
• start time of sub-task 3 - general start time
• end time of sub-task 3 - general start time
• etc. ...

I tried this out by calculating only the start time of sub-task 1 - general start time using this code:

% Extract the start time from results_start_array
start_time = results_start_array(1);

% Extract the end time from the first row in the first table in the first cell of results_start_end
end_time_str = results_start_end{1}{1, 'Time'};

% Convert the end time string to datetime object
end_time = datetime(end_time_str{1}, 'InputFormat', 'HH:mm:ss');

% Convert the start time to datetime object assuming it is in the same day
start_time_dt = datetime(start_time, 'ConvertFrom', 'duration', 'Format', 'HH:mm:ss');

% Calculate the duration between the two times
time_duration = end_time - start_time_dt;

% Display the duration
disp(time_duration);

Which didnt seem to work. What am I doing wrong and how can I fix this?

Thx

Answer 1

[Star Strider]

This seems to work —

load('results_start_array.mat')
whos('-file','results_start_array.mat')

  Name                     Size            Bytes  Class       Attributes

  results_start_array       -                216  duration              

load('results_start_end.mat')
whos('-file','results_start_end.mat')

  Name                    Size             Bytes  Class    Attributes

  results_start_end      25x1             338300  cell               

r_start = results_start_array

r_start = 25x1 duration array
   13:19:21
   17:55:46
   15:30:17
   17:01:24
   09:37:57
   12:28:59
   14:06:50
   15:33:28
   09:40:56
   12:35:40
   14:16:12
   15:42:35
   09:43:18
   10:59:57
   14:01:05
   09:29:51
   11:06:01
   12:30:32
   15:25:37
   09:47:49
   11:08:48
   12:37:49
   09:43:26
   11:18:47
   13:52:57

r_start_end = results_start_end

r_start_end = 25x1 cell array
    {1x12 cell}
    {1x12 cell}
    {1x12 cell}
    {1x12 cell}
    {1x12 cell}
    {1x12 cell}
    {1x12 cell}
    {1x12 cell}
    {1x12 cell}
    {1x12 cell}
    {1x12 cell}
    {1x12 cell}
    {1x12 cell}
    {1x12 cell}
    {1x12 cell}
    {1x12 cell}

r_start_end{1}{1}

ans = 2x1 table
      Time  
    ________

    13:21:26
    13:21:56

r_start_end{end}{1}

ans = 2x1 table
      Time  
    ________

    13:52:57
    13:53:27

for k1 = 1:numel(r_start)
    % Q1 = numel(r_start_end{k1})
    for k2 = 1:numel(r_start_end{k1})
        % Q2 = r_start_end{k1}{k2}
        ET{k1,k2} = r_start_end{k1}{k2}.Time - r_start(k1);
    end
end

ET

ET = 25x12 cell array
  Columns 1 through 10

    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}    {2x1 duration}

  Columns 11 through 12

    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}
    {2x1 duration}    {2x1 duration}

r_start(1)

ans = duration
   13:19:21

r_start_end{1}{1}

ans = 2x1 table
      Time  
    ________

    13:21:26
    13:21:56

ET{1,1}

ans = 2x1 duration array
   00:02:05
   00:02:35

% ET{1,end}
% ET{end,1}

r_start(end)

ans = duration
   13:52:57

r_start_end{end}{end}

ans = 2x1 table
      Time  
    ________

    14:02:12
    14:02:42

ET{end,end}

ans = 2x1 duration array
   00:09:15
   00:09:45

I suggest that you check the results to be certain they make sense. However from my brief inspection of selected results, it doew what I believee you want.

.

[lil brain]

Great! Yes I checked the values and calculated by hand and it all checks out. Great help thx!

[Star Strider]

Thank you!

As always, my pleasure!