Getting weekly averages from hourly data

I need to calculate weekly and daily averages from hourly data of about 1.5 years.
I tried using an array formula (for the first time) based on WEEKNUM from an older thread on this website -

=AVERAGE(IF(D1=$D$2:$D$864,$B$2:$B$864,""))
col D: weeknum and col B: value

I guess, as some of the week numbers are repeated, I get wrong values for those weeks. Is there a solution for this?

My knowledge of array formulas is 1 hr old and I plan to look into the basics but I just need to finish this one task right away.

Thanks in advance!

Hi and welcome to the board

there are different solutions, and your data layout matters, so

to best describe or illustrate your problem you would be better off attaching a dummy workbook, the w
orkbook should contain the same structure and some dummy data of the same type as the type you have in your real workbook - so, if a cell contains numbers & letters in this format abc-123 then that should be reflected in the dummy workbook.

If needed supply a before and after sheet in the workbook so the person helping you can see what you are trying to achieve.

Doing this will ensure you get the result you need!