Power Query Tip: Building Tables from Uneven Lists

When you have a nested list structure where each inner list has a different length, you don’t need to manually pad them with null. A clever trick with double List.Zip does the job for you.

let

 Source = { {"A","B","C"}, {1,2,3,4,5,6}, {"a","b"} },

 Result = Table.FromRows(List.Zip(List.Zip(Source)))

in

 Result

First List.Zip → aligns items across lists, automatically filling shorter lists with null.

Second List.Zip → Restores original alignment with nulls for shorter lists.

Table.FromRows → materializes the structure into a table.

Double List.Zip is a concise way to normalize uneven lists without losing data. Perfect for quick transformations when your source lists don’t line up neatly.