Power Query code to change column types of variable # of columns

[macfuller]

I would like the Power Query equivalent of a For...Next loop to change a variable number of column types.

I import a matrix of which the column names and column count after the 3rd column are variable. Columns 4 thru x come in as type Any and I'd like to convert them to Decimal. I believe I can refer to a column via Table.ColumnNames(tblName){x} but I'm not sure how I could loop through them to make sure all are converted.

The column headers of the matrix are equipment types which the users can adjust depending on which process they're modelling and thus which pieces of equipment are needed. Right now the query is hard-coded with the column names so each iteration requires the query to be changed to the new column names. I'm hoping this is something as simple as an .OtherColumns type of parameter.

 

[RudiS]

This should work:

let
    Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
    Schema = Table.Schema(Source),
    #"Filtered Rows" = Table.SelectRows(Schema, each [Position] >= 3),
    #"Removed Other Columns" = Table.SelectColumns(#"Filtered Rows",{List.First(Table.ColumnNames(#"Filtered Rows"))}),
    ListHeaders = Table.ToList(#"Removed Other Columns"),
    Count = List.Count(ListHeaders),
    Transform = Table.TransformColumnTypes(Source, Table.ToRows(Table.FromColumns({ListHeaders, List.Repeat({type number}, Count)})))
in
    Transform