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StefanoT1982's avatar
StefanoT1982
Regular Visitor
1 year ago
Solved

Evaluating a column through steps without hardcoding the steps' names

Assume I have a simple table with 2 steps: let     Step1 = #table (type table[Names = Text.Type, Money = Int64.Type], {{"John", 1}, {"Jack", 2},{"Mary", 4} }),     Step2 = Table.Skip(Step1,1)    ...
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  • AlienSx's avatar
    AlienSx
    1 year ago
    let
    steps = 
        [
            Step1 = #table (type table[Names = Text.Type, Money = Int64.Type], {{"John", 1}, {"Jack", 2},{"Mary", 4} }),
            Step2 = Table.Skip(Step1,1)
        ],
    money_evolution = ((fields) => Record.FromList(List.Transform(fields, (x) => List.Sum(Record.Field(steps, x)[Money])), fields))(Record.FieldNames(steps))
   
in
    money_evolution
StefanoT1982's avatar
StefanoT1982
Regular Visitor
1 year ago

that's great! would you mind explaining how it works? I'm little familiar with the "=>" function syntax

AlienSx's avatar
AlienSx
Super User
1 year ago

"steps" is record. 

Record.FieldNames(steps)

reads it's fields' names and gets list of names (of steps). 

List.Transform

 goes over the list, picks up every other (step) name and calculates List.Sum of Money column values. 

Record.FromList

folds the results into another record with steps names and Money totals. 

M is functional language so get used to functions syntax and usage.