Get Value X Rows before/ every Xth row

[hwoehler]

Hello everybody,
I would like to display the value of a special row (10th row) along with the last/most recent possible value to divide these two numbers. This should be done for each group (A, B etc.). To illustrate the desired result, use the screenshot (generated in Excel):
The first three columns are already in the Power Bi file. I imagine maybe creating one index column per group, where the close value is taken for every 10th row (index = 10). (marked in color, it is always the 10th row) Then the last most recent close (index = 0) should be divided by the value at index = 10. Maybe someone have a solution for that? The Power BI file with the three first columns can be found here: 
https://we.tl/t-28NZO8BN4Z

Thank you!

Kind Regards, hwoe

[danextian · Accepted solution]

Hi @hwoehler ,

Try this:

• Create a calculated column for the Index within a group.

Index Per Group =
RANKX (
    FILTER (
        Performance130,
        Performance130[Group] = EARLIER ( Performance130[Group] )
    ),
    Performance130[Date],
    ,
    ASC,
    Dense) - 1
​a

• Create this measure:

Value =
VAR __10 =
    CALCULATE (
        SUM ( Performance130[Close] ),
        Performance130[Index Per Group] = 10
    )
VAR __0 =
    CALCULATE ( SUM ( Performance130[Close] ), Performance130[Index Per Group] = 0 )
RETURN
    DIVIDE ( __0, __10 )
​

• Use Group column and Value measure in a visual.