Power BI refer to previous row

Background

sample data

Formula is like:

result = 
if [previous row exists]: 
    (last(target) - first(target))/11 + <previous row value> 
else: 
    first(target)

In PowerBI we cannot refer to self (e.g. previous row same column), but can refer to previous row another column.

So we can make kind of math transformation:

row0 = 1.7
row1 = (2.15 - 1.7)/11  + 1.7
row2 = (2.15 - 1.7)/11 + row1 =  (2.15 - 1.7)/11 * 2 + 1.7
row3 = (2.15 - 1.7)/11 + row2 = (2.15 - 1.7)/11 * 3 + 1.7
...

The transformed formula:

result = 
(last(target) - first(target))/11 * <index of row> + first(target)

Step

• Load Data

• Add Index Column

• Add Custom Column 'result', make formula:

( List.Last(#"Added Index" [target])  - List.First(#"Added Index" [target]))/11 * #"Added Index" {[Index]}[Index] + List.First(#"Added Index" [target])

the List.Last can be replace by List.Max, and List.First can be replaced by Lits.Min regard of context.

• Final Result:

References

thRe: Find value of Previous Row in same columncommunity.powerbi.com