I have used the script below to read in my data (Sample below) and am able to compute the hourly and daily mean of Heat flux (H) by use of accumarraying the date and time stamps. The difficulty is that I also want to accumarray for 15 minute, 30 minute etc averages. How can one do this with the kind of data I have ?
LASfile=fopen('../../data/heat.txt');
Data = textscan(LASfile, '%16c %*24c %s %s %f %f %f %d %d %d %d','headerlines',1);
fclose(LASfile);
H = Data {6};
%%
date_num = datestr(Data{1});
formatIn = 'dd-mmm-yyyy HH:MM:SS';
DateVector = datevec(date_num, formatIn);
%%
% Group by day and hour
[unDates, ~, subs] = unique(DateVector(:,1:4),'rows');
% Accumulate by day
[unDates accumarray(subs, H, [], @mean)]; %computes hourly heat flux
#timeStamp date time Cn2 CT2 H
2012-02-07 11:56:00 2/7/2012 11:56:00 3.11E-13 3.64E-01 330.5
2012-02-07 11:57:00 2/7/2012 11:57:00 2.22E-13 2.60E-01 256.4
2012-02-07 11:58:00 2/7/2012 11:58:00 2.92E-13 3.42E-01 315.3
2012-02-07 11:59:00 2/7/2012 11:59:00 4.07E-13 4.77E-01 404.4
2012-02-07 12:00:00 2/7/2012 12:00:00 3.56E-13 4.17E-01 365.7
2012-02-07 12:01:00 2/7/2012 12:01:00 4.41E-13 5.17E-01 429.3
2012-02-07 12:02:00 2/7/2012 12:02:00 4.23E-13 4.96E-01 416.3
2012-02-07 12:03:00 2/7/2012 12:03:00 3.17E-13 3.72E-01 335.3
2012-02-07 12:04:00 2/7/2012 12:04:00 3.42E-13 4.00E-01 354.7
2012-02-07 12:05:00 2/7/2012 12:05:00 3.43E-13 4.02E-01 355.6
2012-02-07 12:07:00 2/7/2012 12:07:00 2.92E-13 3.42E-01 315.3
2012-02-07 12:08:00 2/7/2012 12:08:00 2.63E-13 3.09E-01 291.7
2012-02-07 12:09:00 2/7/2012 12:09:00 2.45E-13 2.87E-01 276.1
2012-02-07 12:10:00 2/7/2012 12:10:00 3.00E-13 3.52E-01 321.8
2012-02-07 12:11:00 2/7/2012 12:11:00 3.77E-13 4.42E-01 382
2012-02-07 12:12:00 2/7/2012 12:12:00 4.40E-13 5.16E-01 428.9
2012-02-07 12:13:00 2/7/2012 12:13:00 3.60E-13 4.22E-01 369.2
2012-02-07 12:14:00 2/7/2012 12:14:00 4.56E-13 5.35E-01 440.4
2012-02-07 12:15:00 2/7/2012 12:15:00 3.62E-13 4.24E-01 370.5
2012-02-07 12:16:00 2/7/2012 12:16:00 3.48E-13 4.07E-01 359.3
2012-02-07 12:17:00 2/7/2012 12:17:00 3.94E-13 4.62E-01 394.9
2012-02-07 12:18:00 2/7/2012 12:18:00 3.53E-13 4.14E-01 363.5
2012-02-07 12:19:00 2/7/2012 12:19:00 4.47E-13 5.24E-01 433.6
2012-02-07 12:20:00 2/7/2012 12:20:00 4.33E-13 5.07E-01 423.6
2012-02-07 12:21:00 2/7/2012 12:21:00 3.18E-13 3.73E-01 336
2012-02-07 12:22:00 2/7/2012 12:22:00 2.91E-13 3.41E-01 314.7
2012-02-07 12:23:00 2/7/2012 12:23:00 2.71E-13 3.17E-01 297.8
2012-02-07 12:24:00 2/7/2012 12:24:00 3.72E-13 4.36E-01 378.2
2012-02-07 12:25:00 2/7/2012 12:25:00 3.25E-13 3.81E-01 341.8
2012-02-07 12:26:00 2/7/2012 12:26:00 3.66E-13 4.29E-01 373.3
2012-02-07 12:27:00 2/7/2012 12:27:00 3.95E-13 4.63E-01 395.3
2012-02-07 12:28:00 2/7/2012 12:28:00 3.73E-13 4.37E-01 378.9
2012-02-07 12:29:00 2/7/2012 12:29:00 3.31E-13 3.89E-01 346.7
2012-02-07 12:30:00 2/7/2012 12:30:00 3.05E-13 3.57E-01 325.7