How to implement subroutine to calculate mean of daily recorded attributes every 3 month? [closed]

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I a new to energyplus. I am running a code to estimate min Lux every day. I want to use subroutine to calculate mean of these recorded daily min lux every quarter. It means that I want to run the code for whole year and at the end I just want to receive 4 output which are the mean of min lux for each quarter.

your help is highly appreciated.