To expand all lists in a row of lists at the same time without recurring values

Question

I was provided with this succinct and helpful code:

let
Source = #table({"A", "B"}, {{ {1,2}, {3,4}} }),
Expanded = List.Accumulate(
    Table.ColumnNames(Source), 
    Source, 
    (state, column) => Table.ExpandListColumn(state, column))
in
Expanded

Which yields the following result:

I don't want recurrent values in previously processed columns as each follow-on column is processed. I would like to get the following result instead:

Is there a simple modification to the given code that will suffice?

Thanks(:

Answer 1

Can't promise simple, but I have something that will work for sure. 

Objective : You need a code that can combine the columns with an adjusted code so that;

• lists are zipped 
• Inner lists are transformed into records

Step 1 : Expand the list column. This results in a column with nested records which are subsequently expanded.

Step 2 : Create some Dummy text columns that are combined in order to generate the base code (Since you can't use combine columns with nested lists).

Step 3 : Eventually, adjust and remove the steps with the dummy columns.

Code :

let
    Source = #table({"A", "B"}, {{ {1,2}, {3,4}} }),
    #"Merged Columns" = Table.CombineColumns(Source,{"A", "B"}, each List.Transform(List.Zip(_), each Record.FromList(_,{"A","B"})),"Merged"),
    #"Expanded Merged" = Table.ExpandListColumn(#"Merged Columns", "Merged"),
    #"Expanded Merged1" = Table.ExpandRecordColumn(#"Expanded Merged", "Merged", {"A", "B"}, {"A", "B"})
in
    #"Expanded Merged1"