unpivot table with milestones

Hi Anonymous 

yes, make sure your headers contain characters that make splitting like in the following example possible:

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45W8nQxVNJRAmEjIDYGYhOlWB2QOIhvCsRmQGwOxBZKsbEA", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type text) meta [Serialized.Text = true]) in type table [ID = _t, A_1 = _t, A_2 = _t, B_1 = _t, B_2 = _t]),
    #"Unpivoted Other Columns" = Table.UnpivotOtherColumns(Source, {"ID"}, "Attribute", "Value"),
    #"Split Column by Delimiter" = Table.SplitColumn(#"Unpivoted Other Columns", "Attribute", Splitter.SplitTextByDelimiter("_", QuoteStyle.Csv), {"Attribute.1", "Attribute.2"}),
    #"Pivoted Column" = Table.Pivot(#"Split Column by Delimiter", List.Distinct(#"Split Column by Delimiter"[Attribute.1]), "Attribute.1", "Value")
in
    #"Pivoted Column"

attaching file as well