Hi,
I have a little calculation problem:
I want to @sub(A1,B1) and write the result (72) at A2. Next step A2-B2 (72-18)--> result (54) at A3... and so on. The dataset must be flexible, because the input is not only 3 rows long.
Thank you for your help!
Add an AttributeManager to your workspace after the Reader.
In that transformer, enable the adjacent features. Number of prior features = 1
Calculate the A value in that AttributeManager as: @sub(features[-1].A, features[-1].B)
I think that should do the trick.
In the AttributeManager you can use the adjacent features option to access attributes from previous features, as long as everthing remains in that order you can do it.
Check out Excercise 3 of the Advanced Attribute Handling part of the 2018 Desktop Advanced course, it does something very close to what you're trying to do here.
Thank you for your response and help. The exercise is a little bit different and when I try it, I don´t get the right result:
In the exercise the @sub from month to month is taken and is writen in a new attribute.
I tested a little bit around with the "Substitue Missing, Null and Empty by" option:
The result isn´t in cell A2 (all results are featureu-1]), but it is caluclate right:
Thank you for your response and help. The exercise is a little bit different and when I try it, I don´t get the right result:
In the exercise the @sub from month to month is taken and is writen in a new attribute.
I tested a little bit around with the "Substitue Missing, Null and Empty by" option:
The result isn´t in cell A2 (all results are featureu-1]), but it is caluclate right:
You need to ignore the first row with a conditional value.
Before the AttributeManager, add a Counter. Then, in the AttributeManager for the A value, you need to put a Conditional Value. Something like this:
If _counter != 0 Then @sub(featurest-1].A, featurest-1].B)
Else (do nothing)
Hope that helps.
Sorry, I think I was explaining myself very badly.
I have attached a workspace with what I think is the result you want.
@oscard
If it is to excell, you can also write the expression (in english and quoted) to excell itself.
So in A2 "=A1+B1"
A3 "=A2+B2"
etc.
Use stringconcatenator.
Or you can expose xls_row_id then explode and do the expression.
Or of course, as it is only one row down, you canuse adjacent features. (But what if it is not just 1 row down?) You than need to use stringconcatenation anyway.
@oscard thanks! It works.