List.Positions

Syntax

List.Positions(list as list) as list

About

Returns a list of offsets for the specified input list.

• list: The input list.

When using List.Transform to change a list, the list of positions can be used to give the transform access to the position.

Example 1

Find the offsets of values in the list {1, 2, 3, 4, null, 5}.

Usage

List.Positions({1, 2, 3, 4, null, 5})

Output

{0, 1, 2, 3, 4, 5}

Example 2

Create a table that assigns an ID to each customer based on the customer's position in the list.

Usage

let
    customers = {"Alice", "Bob", "Charlie", "Diana"},
    resultTable =
        Table.FromRecords(
            List.Transform(
                List.Positions(customers),
                each [
                    IDNumber = _ + 1,    // Make it 1-based
                    CustomerName = customers{_}
                ]
            ),
            type table [IDNumber = Int64.Type, CustomerName = text]
        )
in
    resultTable

Output

#table (type table[IDNumber = Int64.Type, CustomerName = text],
{
    {1, "Alice"},
    {2, "Bob"},
    {3, "Charlie"},
    {4, "Diana"}
})