# How to compute the frequency of hourly/daily observation?

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aa on 15 Feb 2021
Edited: Cris LaPierre on 17 Feb 2021
Hi everyone,
I want to compuet the hourly/daily number of observations. My data consistes of six colums (YYYY MM DD HH MM SS). Each date-time entry show one observation.
The measurements are uneven i.e. 0 to 100 etc. From the data set presnted below: I am interested to calcualet the hourly observations from 2015-05-06-10-35-00 to 2015-05-08-22-35-00 and same for the daily observations. (data also attached in excel sheet).
Thank you!

Cris LaPierre on 15 Feb 2021
I would then create a new column and use datetime to convert YYYY MM DD HH MM SS to a datetime.
I would then use groupsummary to calculate a summary using 'hour' or 'day' as my grouping method.
Cris LaPierre on 15 Feb 2021
You will have to create your groupbins manually rather than use 'day' and 'hour'. To get a result for each bin, use the 'IncludeEmptyGroups' and 'IncludeMissingGroups' options.
% Create groupbins for hourly and daily
startT = datetime(2016,12,05,13,35,00);
endT = datetime(2016,12,10,13,35,00);
newT_hr = startT:hours(1):endT;
newT_day = startT:caldays(1):endT;
% Count groups
hrAvg = groupsummary(data,"timestamp",newT_hr,"IncludeEmptyGroups",true,"IncludeMissingGroups",true)
dayAvg = groupsummary(data,"timestamp",newT_day,"IncludeEmptyGroups",true,"IncludeMissingGroups",true)