Summing consecutive blocks of cells

[Mr.T]

Hi there, I've got a bit of an issue summing up cells in excel.

I have a data set from a solar monitor, with a value taken every half hour for one consecutive year, so 48 points per day. There are two columns, the date/time stamp and my measurement, incidently solar flux. I want to produce a summary that gives the sum of the solar flux values for each day. So in essence I need to sum up rows 1:48, then 49-96, 97-144, etc...

I've tried creating the pattern by manually selecting the cells to add for 10 days and then dragging the formula down, but it doesn't advance properly. I've also tried the SUMIF function with no luck.

Can anyone help me out. Thanks and Cheers, remember to enjoy a beer today.

 

[PaddyD]

hi - welcome to the board!

if the dates are stored as genuine dates (i.e. as numbers - a thing you can check with =isnumber(ref) for one of the dates) then this is the sort of thing that pivot tables are designed for.

select the range, go to data | pivot table...click through the obvious bits, set up the pivot layout with dates in the row & sum of values in the data area.

once on the sheet, right-click the date area, go to group & group the dates by day.

if the dates aren;t genuine, post back with examples of them & we can fix them up.

 

[Mr.T]

Thanks Paddy, the pivot tables were just the trick. Very slick.

Out of curiosity, do you know how many data points a table can handle, my set is 17526 cells long, and I had to break it up into 4 month intervals?

Again, thanks for the reply, I'm officially a big fan of this message board.

Tom

 

[PaddyD]

"Out of curiosity, do you know how many data points a table can handle, my set is 17526 cells long, and I had to break it up into 4 month intervals? "

review the excel help file for 'Excel specifications and limits' - unique item per field = 32,500; number of fields = limited by memory