Convert hourly to daily data

Hi all,

I have some data in an hourly basis and I want to convert them to daily (each day to be the average of 24 rows) .

I have created the following loop but I am missing one value. For the specific period I should be receiving 1461 rows (days) but I am receiving 1460.

Can someone please help me?

t=1;
k=1; step = 24;
for i - step:step:length(x)-step;
    if i > step; a = x(i-step:i); else a = x(k:i); end;
    AverageDailyData(k,t) = mean(a)q
    k=k+1;
end

[Raghunandan V]

The code you have written is very confusing. i think it can be done in much simpler way. Can you share the data?. I can look at the data and then write the code

[Guillaume]

More than confusing, the code is not valid matlab syntax.

[Christos Kaskouras]

I am sorry for that. I am kind of "old school" programmer. However, I am loosing just one row

Attached you can finf the file.

Thank you!

Answer 1

[Andrei Bobrov]

T = readtable('IT_GR_data.csv','ReadV',1);
T.Properties.VariableNames{1} = 'Date';

TT = table2timetable(T,'RowTime','Date');
TTout = retime(TT,'daily','mean');

[Youssef saad]

i want to covert my data (text) 1 colomn 8760 row from hourly to daily 1 colomn 365 row,

basicaly i want to calculate the daily average of my data to obtain a 1x365 dataset

can you help please help me

[Eshrat Jahan]

@andrei Bobrov can you kindly write the code with respect to older Matlab versions like 2015.

Answer 2

[Guillaume]

Because of the typos and the lack of comments, it's hard to tell how your data is stored. The simplest way to achieve what you want is to store your data in a timetable (the creation of which is probably just one line), then retime that timetable:

hourlydata = timetable(yourdatetimecolumn, yourdatacolumn);  %or some other way of creating a timetable
dailydata = retime(hourlydata, 'daily', 'mean')
%all done

This is probably the most reliable and clearest way to do it. It will work even if you're missing some hours, some days are not complete, or if your data is not ordered chronologically. I would strongly recommend that you use this method.

As you seem to imply that your data is ordered chronologically and that you've got the full hourly data for each day, you could just average in groups of 24 rows. You shouldn't use a loop for that:

hourlydata = rand(72, 1);  %demo data, supposed to represent 3 days of hourly data

dailydata = mean(reshape(hourlydata, 24, [])).'  %rearrange the hourly data in daily columns and take the mean of the 24 hours of each column.

[Christos Kaskouras]

I will try this out.

Thank you!

[Guillaume]

Well, with your text file then that's trivially loaded into a timetable as shown by Andrei. You don't even have to worry about renaming the datetime column. You then apply retime as I've shown above:

hourlydata = table2timetable(readtable('IT_GR'));
dailydata = retime(hourlydata, 'daily', 'mean')

[Andrei Bobrov]

+1

[Francisco Molteni]

but when you have gaps in your data the timetable can not remove that and you will have errors, how you can solve that ?

710724 NaN

710725 NaN

710726 NaN

710727 NaN

710728 NaN

710729 NaN

710730 NaN

710731 NaN

710732 NaN

710733 NaN

710734 NaN

710735 NaN

710736 68.5000000000000

710737 68.7222222222222

710738 69.1805555555556

710739 69.1111111111111

710740 69.5833333333333

710741 69.0694444444444

710742 72.9722222222222

710743 71.6527777777778

710744 73.1666666666666

710745 74.2638888888889

710746 77.0972222222222

710747 75.9444444444444

710748 74.1250000000000

710749 73.9861111111111

710750 73.5555555555556

710751 70.0694444444444

710752 68.6666666666666

710753 69.7361111111111

710754 73.1527777777778

710755 75.9305555555556

710756 76.4583333333333

710757 77.3194444444444

710758 78.3888888888889

710759 80.4027777777778

710760 80.1111111111111

710761 80.7916666666667

710762 83.6805555555556

710763 79.9027777777778

710764 78.9444444444444

710765 77.7916666666667

710766 77.2500000000000

Answer 3

[Christos Kaskouras]

Solve it.

Thank you guys!