Power Query: How do I add a specific List/Vector as a Column

Question

I have a simple problem. Let's assume I have the following

Now I want to add a specific vector or list for example (1,2,2,1) as an additional column and it should look like

When I add "Custom Column", how do I have to enter this list that it creates exactly this column? It should not be a index column or a calculated column because I want to specify the values depending on another column manually. It seems like it is a very simple task, but I couldn't find any solutions yet! (I feel very stupid xD)

pls help

Thank you!

Answer 1

let Source = #table({"Column1"},{{"A"},{"B"},{"C"},{"D"}}),
Add = {{1,2,2,1}},
part1=Table.ToColumns(Source) & Add,
part2= Table.FromColumns(part1,Table.ColumnNames(Source)&{"Column2"})
in part2

or perhaps, if grabbing column from another table

let Source = #table({"Column1"},{{"A"},{"B"},{"C"},{"D"}}),
part1=Table.ToColumns(Source) & Table.ToColumns(Table.SelectColumns(SomeOtherTable,"Column9")),
part2 = Table.FromColumns(part1,Table.ColumnNames(Source)&{"Column2"})
in part2