First, I would use a StringReplacer to remove the spaces around the character "=". The goal is getting:
A-1 100 100
A-2 250 (100-250)=50
A-3 300 (250-300)=50
B-1 10 10
B-2 30 20
B-3 80 50
C-1 40 40
C-2 100 60
C-3 200 100
Then I would use AttributeSplitter using a blank space " " as the character used for splitting. That way you will get a list with 3 elements in every feature:
_list{0} --> Class
_list{1} --> Length
_list{2} --> Range
Sorry, I was not clear. Length-ranges (column in yellow) it is what I want to get. I have only class and Length.
sampledata.xlsx
I think now I do understand what you need.
You need to use AttributeManager enabling adjacent features:

And then create the Range attribute with a conditional value:


xlsxr2none.fmw