Conditional If or Switch using var DAX

Hi Anonymous - I don't think this is possible using DAX, but it is possible using Power Query.  Please try the following:

let
  Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("dY5BCsAgDAT/krPCRpPYvkX8/zcapYQW9BKWYWdJ78SUiEv1C+aMAmSYB2CHRupUwjg1ajTadfsVtcUl+OtPqB5U7LelawtbNh0L51hp3y9pjAc=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [S.No = _t, ID = _t, OPS = _t, PP = _t]),
  #"Change Data Types" = Table.TransformColumnTypes(Source,{{"S.No", Int64.Type}, {"ID", Int64.Type}}),
  Buffer = Table.Buffer ( #"Change Data Types" ),
  #"Add Conditional Result" = Table.AddColumn(Buffer, "Condition Result", each 
    let 
      i=[S.No], x=[ID], OPS=[OPS], PP=[PP], t=Buffer,
      text1 = Text.Length(OPS), text2 = Text.Length(PP),
      test_1 = 
        if OPS = PP and not ( text1 = 0 or text2 = 0 ) 
        then "Match" 
        else null,
      test_2 = 
        if ( text1 = 0 or text2 = 0 ) 
        then 
          if
            List.ContainsAny( 
              List.Combine( 
                { 
                  Table.SelectRows( t , each [ID] = x and ( [S.No] = i - 1 or [S.No] = i + 1) )[OPS],
                  Table.SelectRows( t , each [ID] = x and ( [S.No] = i - 1 or [S.No] = i + 1) )[PP]
                } 
              ) ,
              { OPS , PP } 
            ) 
          then "Extra Population" 
          else null
        else null,
      test_3 = 
        if OPS <> PP 
        then "Non Match" 
        else null, 
      Result = List.First( List.RemoveNulls( { test_1, test_2, test_3, "Missed by ML" } ) )
    in 
      Result
  )
in
  #"Add Conditional Result"