Organizing and calculating with timestamps and numbers.

I have a matrix, in which in the first column I have timestamps, usually one every 10 seconds, but it is not constant, and sometimes there are more than 10 seconds between one timestamp and another. The second column is power readings (numbers). A brief example would be something like this:

1570226408    1000022
1570226418    1000022
1570226431    1000022
1570226438    1000032
1570226448    1000032
1570226458    1000032
1570226469    1000032

I converted the timestamps into DateTime format, but the problem is that I can not have in the same matrix, two different classes (DateTime and double).

What I want to do is to be able to process that file, to calculate the total power per hour, per day, the energy for each hour or the total energy per day. Do you have any idea about how to do this?

PS. I managed to do this in a very rustic way: convert the timestamp into date number and work with the decimals of those date numbers to differentiate hours, but I reckon there should be a more efficient and straightforward way to do this.

[John Doe]

Did my suggestions work for you?

Answer 1

[John Doe]

Create a table - a table can handle both datetime, double, single etc.

t = array2table(data)

You can then do your analysis as you please using datetime. To call a variable use:

t.VariableName

Timetable can also be used.

doc timetable

[Neko Benítez]

Thank you very much, John. I checked, and it worked. I have to check the advantages of using timetable instead of just a table. As I said, I need to group data for each hour, day, and so on. Once I have all the time data in column 1 of the table, do you suggest any precise way to group the matching data for hours, days and so on?

[Stephen23]

https://www.mathworks.com/matlabcentral/answers/232203-how-to-do-monthly-average-in-a-table

https://www.mathworks.com/matlabcentral/answers/317655-calculate-avergae-values-per-hour-day-month-and-year#answer_247990

https://www.mathworks.com/help/matlab/ref/double.groupsummary.html

etc.