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How to average seconds data to minutes data?

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Gnanamoorthy P
Gnanamoorthy P on 6 Nov 2020
Commented: Steven Lord on 6 Nov 2020
I have a one Hz set of data for whole day, so i would like to average this seconds data into each minutes data. Please give your code and suggestions.
Thanks you.

Answers (1)

Dave B
Dave B on 6 Nov 2020
It sounds like you want to use the first column of your CSV which has times, and for each minute extract compute the average of the remaining columns.
I'll use tables and groupsummary (introduced in 2018a) which are great for this kind of problem:
tbl = readtable('PGM.csv'); % Read the data in
% Convert first column to a datetime the date part is arbitrary here (because they're not
% supplied in the file), but it's so easy to do this with the datetime type!
tbl.Var1 = datetime(tbl.Var1,'InputFormat','HH:mm');
result=groupsummary(tbl,"Var1","minute","mean",["Var2" "Var3" "Var4" "Var5"]);
% The results for the 4 columns are in result.mean_Var2, result.mean_Var3 etc.
% Additional notes:
% You can strip off the date part and go back to a string using:
dt = extractAfter(string(result.minute_Var1)," ");
% You could plot the first column of data with:
plot(datetime(extractAfter(string(result.minute_time),"" "")),result.mean_Var2)
A great feature of groupsummary,is that if you wanted some other summary statistics in addition to mean those are easy to get in the same shot, see the documentation for details.
Steven Lord
Steven Lord on 6 Nov 2020
Another alternative would be to store the data in a timetable and use retime.

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