how to extract time after calculating mean and standard deviation?
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Hello all of my Matlab friends,
I have a data file of every minute data for one year (from march 1 to December 31) as follows:
Date Time O3 Tb TL Prs
2009-03-01 00:00:00 14.0 25.6 56.8 740.2
2009-03-01 00:01:00 13.9 25.6 56.8 740.2
2009-03-01 00:02:00 13.8 25.6 56.8 740.2
2009-03-01 00:03:00 13.6 25.6 56.8 740.2
2009-03-01 00:04:00 13.4 25.6 56.8 740.2
2009-03-01 00:05:00 13.3 25.6 56.8 740.2
2009-03-01 00:06:00 13.2 25.6 56.8 740.2
2009-03-01 00:07:00 13.4 25.6 56.8 740.2
2009-03-01 00:08:00 13.4 25.6 56.8 740.2
2009-03-01 00:09:00 13.3 25.6 56.8 740.2
2009-03-01 00:10:00 13.4 25.6 56.8 740.3
2009-03-01 00:11:00 13.1 25.6 56.8 740.3
2009-03-01 00:12:00 13.6 25.6 56.8 740.2
2009-03-01 00:13:00 13.7 25.6 56.8 740.2
2009-03-01 00:14:00 13.6 25.5 56.8 740.3
2009-03-01 00:15:00 13.5 25.5 56.8 740.3
2009-03-01 00:16:00 13.3 25.5 56.8 740.3
2009-03-01 00:17:00 13.3 25.5 56.8 740.3
2009-03-01 00:18:00 13.8 25.5 56.8 740.3
2009-03-01 00:19:00 13.8 25.5 56.8 740.3
2009-03-01 00:20:00 14.0 25.5 56.8 740.3
2009-03-01 00:21:00 14.3 25.5 56.8 740.3
2009-03-01 00:22:00 14.2 25.5 56.8 740.3
2009-03-01 00:23:00 14.2 25.4 56.8 740.3
2009-03-01 00:24:00 14.6 25.4 56.8 740.3
2009-03-01 00:25:00 14.4 25.4 56.8 740.4
2009-03-01 00:26:00 14.3 25.4 56.8 740.3
2009-03-01 00:27:00 14.3 25.4 56.8 740.4
2009-03-01 00:28:00 14.0 25.4 56.8 740.4
2009-03-01 00:29:00 14.0 25.4 56.8 740.3
2009-03-01 00:30:00 14.2 25.4 56.8 740.4
2009-03-01 00:31:00 14.3 25.4 56.8 740.4
2009-03-01 00:32:00 14.0 25.4 56.8 740.4
2009-03-01 00:33:00 14.2 25.4 56.8 740.4
2009-03-01 00:34:00 14.3 25.4 56.8 740.4
2009-03-01 00:35:00 14.2 25.4 56.8 740.5
2009-03-01 00:36:00 14.1 25.4 56.8 740.5
2009-03-01 00:37:00 13.8 25.4 56.8 740.4
2009-03-01 00:38:00 14.1 25.4 56.8 740.4
2009-03-01 00:39:00 14.3 25.4 56.8 740.5
2009-03-01 00:40:00 14.0 25.4 56.8 740.4
2009-03-01 00:41:00 14.2 25.4 56.8 740.4
2009-03-01 00:42:00 14.1 25.4 56.8 740.5
2009-03-01 00:43:00 13.9 25.4 56.8 740.5
2009-03-01 00:44:00 13.9 25.4 56.8 740.5
2009-03-01 00:45:00 14.0 25.4 56.8 740.4
2009-03-01 00:46:00 14.1 25.4 56.8 740.5
2009-03-01 00:47:00 13.9 25.4 56.8 740.5
2009-03-01 00:48:00 13.9 25.4 56.8 740.5
2009-03-01 00:49:00 14.0 25.4 56.8 740.5
2009-03-01 00:50:00 13.9 25.5 56.8 740.5
2009-03-01 00:51:00 14.1 25.5 56.8 740.5
2009-03-01 00:52:00 14.0 25.5 56.8 740.5
2009-03-01 00:53:00 14.2 25.5 56.8 740.5
2009-03-01 00:54:00 14.2 25.5 56.8 740.6
2009-03-01 00:55:00 14.0 25.5 56.8 740.6
2009-03-01 00:56:00 14.0 25.5 56.8 740.5
2009-03-01 00:57:00 13.8 25.5 56.8 740.5
2009-03-01 00:58:00 13.7 25.5 56.8 740.5
2009-03-01 00:59:00 13.3 25.5 56.8 740.5
2009-03-01 01:00:00 13.2 25.5 56.8 740.5
2009-03-01 01:01:00 13.3 25.5 56.8 740.5
2009-03-01 01:02:00 13.9 25.5 56.8 740.6
2009-03-01 01:03:00 13.8 25.5 56.8 740.5
2009-03-01 01:04:00 13.6 25.6 56.8 740.5
2009-03-01 01:05:00 13.9 25.6 56.8 740.6
2009-03-01 01:06:00 14.1 25.6 56.8 740.5
2009-03-01 01:07:00 13.9 25.6 56.8 740.6
2009-03-01 01:08:00 14.0 25.6 56.8 740.6
2009-03-01 01:09:00 13.8 25.6 56.8 740.6
2009-03-01 01:10:00 13.8 25.6 56.8 740.6
2009-03-01 01:11:00 14.0 25.6 56.8 740.6
2009-03-01 01:12:00 13.9 25.6 56.8 740.6
2009-03-01 01:13:00 14.0 25.6 56.8 740.6
2009-03-01 01:14:00 14.4 25.6 56.8 740.6
2009-03-01 01:15:00 14.5 25.6 56.8 740.7
2009-03-01 01:16:00 14.2 25.6 56.8 740.6
2009-03-01 01:17:00 14.1 25.6 56.8 740.6
2009-03-01 01:18:00 14.2 25.6 56.8 740.6
2009-03-01 01:19:00 14.3 25.6 56.8 740.6
2009-03-01 01:20:00 14.6 25.6 56.8 740.6
2009-03-01 01:21:00 14.5 25.6 56.8 740.6
2009-03-01 01:22:00 14.3 25.6 56.8 740.6
2009-03-01 01:23:00 14.8 25.6 56.8 740.6
2009-03-01 01:24:00 14.4 25.6 56.8 740.6
2009-03-01 01:25:00 14.6 25.6 56.8 740.6
2009-03-01 01:26:00 14.7 25.6 56.8 740.7
2009-03-01 01:27:00 14.6 25.6 56.8 740.6
2009-03-01 01:28:00 14.6 25.7 56.8 740.6
2009-03-01 01:29:00 14.5 25.7 56.8 740.7
2009-03-01 01:30:00 14.6 25.7 56.8 740.7
2009-03-01 01:31:00 14.6 25.7 56.8 740.7
2009-03-01 01:32:00 14.1 25.7 56.8 740.7
2009-03-01 01:33:00 14.0 25.7 56.8 740.7
2009-03-01 01:34:00 13.9 25.7 56.8 740.7
2009-03-01 01:35:00 13.7 25.7 56.8 740.7
2009-03-01 01:36:00 13.6 25.7 56.8 740.7
2009-03-01 01:37:00 13.4 25.7 56.8 740.6
2009-03-01 01:38:00 13.8 25.7 56.8 740.7
2009-03-01 01:39:00 13.6 25.7 56.8 740.7
2009-03-01 01:40:00 13.9 25.7 56.8 740.7
2009-03-01 01:41:00 14.1 25.7 56.8 740.7
2009-03-01 01:42:00 14.2 25.7 56.8 740.7
2009-03-01 01:43:00 14.2 25.8 56.8 740.7
2009-03-01 01:44:00 14.3 25.8 56.8 740.7
2009-03-01 01:45:00 14.2 25.8 56.8 740.7
2009-03-01 01:46:00 14.5 25.8 56.8 740.8
2009-03-01 01:47:00 14.3 25.8 56.8 740.8
2009-03-01 01:48:00 14.1 25.8 56.8 740.8
2009-03-01 01:49:00 14.3 25.8 56.8 740.8
2009-03-01 01:50:00 14.4 25.8 56.8 740.8
2009-03-01 01:51:00 14.3 25.8 56.8 740.8
2009-03-01 01:52:00 14.5 25.8 56.8 740.8
2009-03-01 01:53:00 14.3 25.8 56.8 740.8
2009-03-01 01:54:00 14.4 25.8 56.8 740.8
2009-03-01 01:55:00 14.7 25.8 56.8 740.8
2009-03-01 01:56:00 14.6 25.8 56.8 740.8
2009-03-01 01:57:00 14.7 25.8 56.8 740.8
2009-03-01 01:58:00 14.1 25.9 56.8 740.8
2009-03-01 01:59:00 14.5 25.9 56.8 740.8
Does any body have any idea how can I get the 1 hour mean and std for the last four parameters and then extracting the first date how can I make a new array to store my results as follows:
Date Time O3(mean) std Tb std TL std Prs std
2009-03-01 00:00:00 14.0 x 25.6 x 56.8 x 740.2 x
2009-03-01 01:00:00 13.2 x 25.5 x 56.8 x 740.5 x
I don't have any idea how can I make the loop for my one year data and how to extract the date and time. As a matlab novice I can just calculate the mean and std and can write them in a new file.
I will highly appreciate any suggestions regarding the aforementioned problem and thank you very much in advance.
2 Comments
Jan
on 11 Sep 2012
Please add important information inside the question by editing it, not as comment, which will disappear (optically) as soon as three other comments have been posted. Please format your code properly. The samller the example data, the more likely is that users read the question until the end. I think 10 lines are enough.
Accepted Answer
Andrei Bobrov
on 11 Sep 2012
Edited: Andrei Bobrov
on 11 Sep 2012
please try this is code (corrected)
f = fopen('yourdata.txt');
c = textscan(f,'%s %s %f %f %f %f','HeaderLines',1,'CollectOutput',1);
fclose(f);
cc = num2cell(c{1},1);
dd = strcat(cc{:});
dv = datevec(dd,'yyyy-mm-ddHH:MM:SS');
[a,b,x] = unique(dv(:,1:4),'rows','first');
[z,y] = ndgrid(x,1:size(c{2},2));
out1 = zeros(size(a,1),size(c{2},2)*2);
out1(:,1:2:end) = accumarray([z(:),y(:)],c{2}(:),[],@mean);
out1(:,2:2:end) = accumarray([z(:),y(:)],c{2}(:),[],@std);
out = [c{1}(b,:),num2cell(out1)];
3 Comments
More Answers (1)
Jan
on 11 Sep 2012
You overwrite the toolbox function mean() by a local variable of the same name. There should be an MLint warning. The same for std() .
The values of Time and Time_mean_std are overwritten in each iteration. When you want to collect them, use something like Time(i) and Time_mean_std(i). To learn how to make this efficient, search for "pre-allocation" in this forum.
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