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Averaging and summing parts of a column based on date

Asked by Wendy Cameron on 24 Jan 2019
Latest activity Commented on by Wendy Cameron on 30 Jan 2019
Greetings Matlab community
I have some very large data sets and I am wanting to sum and average parts of a table column based on the date. I have multiple readings of e.g. temperature for a given date and want to both sum and average these for each given date and get a corresponding table with the results.
A VERY cut down version of the data is attached and I want to get a result that has three columns - the date, the average Maxium temperature and the Total max temp for each date.
Much appreciated

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2 Answers

Answer by per isakson
on 25 Jan 2019
Edited by per isakson
on 25 Jan 2019
 Accepted Answer

Ten hours without an answer. Here is the result from my first experiment with timetable. See retime Resample or aggregate data in timetable, and resolve duplicate or irregular times
%%
T = readtable('Matlab question.xlsx');
%%
TT = table2timetable( T, 'rowTimes','Var1' );
%%
dm = retime( TT, 'daily','mean' );
%%
dx = retime( TT, 'daily','max' );
%%
ds = retime( TT, 'daily','sum' );

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Thank you. That works. I am now wondering if one can turn a timetable e.g. dm etc, back to a table?

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Answer by Andrei Bobrov
on 25 Jan 2019

T = readtable('Matlab question.xlsx','Ra','A2:B109','ReadV',0);
out = rowfun(@tempfun,T,'G','Var1',...
'OutputV',...
{'MeanTemp' 'MaxTemp'});
function varargout = tempfun(x)
varargout = {mean(x),max(x)};
end

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