adapting the range for certain functions according to values in a list

Hi all,

I have a list with over 15 000 entries that give several values per day (sometime once per hour, sometimes more) and now I want to apply certain functions to all valules that were recorded in a certain day. For simplicity let's say a daily min and max. These min and max values shall be calculated for every row.

Is there a way to do it? I have already marked the first (f) and last (l) entries of a day in column D.

Possible approach (but I don't know how to do this in Excel): to calculate the daily min in cell E4, we could start from D4 and move up to the next "f" in D2 and than move one cell to the left to C2 as the start of the range in the min function. And for the end of the range we start again from D4 and move down to the next "l" in D6, move one cell to the left (C6). This rule I could apply to all 15 000 rows and always adapt the range accordingly.

- What function can I use to find the next cell in a certain direction that contains a specific value (in this case "f" or "l")?

- how can I "move to the left"? just =column(cell with "f" or "l")-1?

- to convert the adjusted position to a reference I would use =indirect(string of adjusted column and row with the "l" or "f")

thanks in advance.