Forum Discussion
List.Accumulate & Table.AddColum with Iteration Step Counter
Instead of just iterating over the formula names, iterate over a list of records that include both the formula and its index:
let formulas = {"Deviation1", "Deviation2"}, components = { {"C1", "C2"}, {"C3", "C4"} }, baseTable = YourBaseTable, result = List.Accumulate( List.Zip({formulas, components}), baseTable, (state, current) => let formulaName = current{0}, compPair = current{1}, newCol = Table.AddColumn(state, formulaName, each [Record.Field(_, compPair{0})] - [Record.Field(_, compPair{1})]) in newCol ) in result
Explanation
- formulas is your list of formula names.
- components is a list of field pairs used in each formula.
- List.Zip combines them into a list of {formulaName, {component1, component2}}.
- List.Accumulate loops through and adds a new column each time.
- The counter is implicitly handled by the position in the zipped list.
Hi Goodkat ,
When you use List.Accumulate, you don’t just have to pass the table along but you can also carry a counter with it, think of it Goodkat like keeping a little notebook that says “here’s my table so far, and here’s which loop I’m on.” Each time the loop runs, you add your new column to the table and bump the counter up by 1, that way, instead of hard‑coding {0}, you just use the counter value to pick the right component for that step.
Did it work? 👍 A kudos would be appreciated
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