Forum Discussion

pontushaglund's avatar
7 years ago
Solved

Finding first, second, third occurence

Hi there.

 

I have this table of data:

I need to calculate a penalty for each row where the penalty is increased for conscutive rows:

The first row with a value above threshold (Index 1, 5, 10) should get the value 1000.

The second consecutive row (Index 2, 6, 11) should get the value 2000.

The third and following rows (Index 3, 7-8, 12) shoud get the value 5000.

 

I could do a merge to find the preceding row for each row, see if above threshold is true or false and then know if it is the first case but would prefer a nicer way. Is there one?

 

Please note that the actual data set has data for every hour the last five years, in total about 44000 rows. My experience is that some DAX-examples that work fine on 20 rows never executes on 44000 rows. I would prefer a solution in Power Query.

 

Thanks,

 

Pontus

  • This could be another option for you:

     

     

    let
        Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMlTSUTI0MACSlgZKsTrRSkYgASMkAWOQgCmSgAmQaYHEN0U3wgwkYIgkYI5uhAVIwARJwBJsBoIPZqNoMQS71AxZBOxUuEtiAQ==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type text) meta [Serialized.Text = true]) in type table [Index = _t, Value = _t, Threshold = _t]),
        
        ChangedType = Table.TransformColumnTypes(Source,{{"Index", Int64.Type}, {"Value", Int64.Type}, {"Threshold", Int64.Type}}),
        
        AddAboveThreshold = Table.AddColumn( ChangedType, "AboveThreshold", each [Value] > [Threshold], type logical),
        
        Grouping = Table.Group( AddAboveThreshold, {"AboveThreshold"}, {"AllRows", each _, type table}, GroupKind.Local),
        
        ValueMapping = #table( type table [Index3= Number.Type, AddedValue = Number.Type], { {1, 1000}, {2, 2000}, {3, 5000} } ),
        
        fnAddValue = ( tbl as table ) as table =>
            let
                AddIndxCol = Table.AddIndexColumn( tbl, "Index2", 1, 1 ),
                MergeTables = Table.NestedJoin( AddIndxCol, {"Index2"}, ValueMapping, {"Index3"}, "JoinedTable", JoinKind.LeftOuter ),
                ExpandCol = Table.ExpandTableColumn( MergeTables, "JoinedTable", {"AddedValue"} ),
                FillDown = Table.FillDown( ExpandCol, {"AddedValue"})
            in
                Table.SelectColumns(FillDown, {"Index", "Value", "Threshold", "AddedValue"} ),
        
        ModifyTableCell = Table.AddColumn( 
                                    Grouping, 
                                    "AddValue", 
                                    each 
                                        if 
                                            [AboveThreshold] = true 
                                         then 
                                            fnAddValue( [AllRows] ) 
                                        else 
                                            Table.SelectColumns( [AllRows], {"Index", "Value", "Threshold"} ),
                                    type table ),
                                    
        ExpandedAddValue = Table.ExpandTableColumn(
                                ModifyTableCell, 
                                "AddValue", 
                                {"Index", "Value", "Threshold", "AddedValue"}
                          ),
        RemovedOtherColumns = Table.SelectColumns(
                                                 ExpandedAddValue,
                                                 {"Index", "Value", "Threshold", "AddedValue"}),
                                                 
        ChangedType2 = Table.TransformColumnTypes(
                                RemovedOtherColumns,
                                {
                                    {"Index", Int64.Type}, 
                                    {"Value", type number}, 
                                    {"Threshold", type number}, 
                                    {"AddedValue", Int64.Type}
                                }
                            )
    in
        ChangedType2

3 Replies

  • This could be another option for you:

     

     

    let
        Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMlTSUTI0MACSlgZKsTrRSkYgASMkAWOQgCmSgAmQaYHEN0U3wgwkYIgkYI5uhAVIwARJwBJsBoIPZqNoMQS71AxZBOxUuEtiAQ==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type text) meta [Serialized.Text = true]) in type table [Index = _t, Value = _t, Threshold = _t]),
        
        ChangedType = Table.TransformColumnTypes(Source,{{"Index", Int64.Type}, {"Value", Int64.Type}, {"Threshold", Int64.Type}}),
        
        AddAboveThreshold = Table.AddColumn( ChangedType, "AboveThreshold", each [Value] > [Threshold], type logical),
        
        Grouping = Table.Group( AddAboveThreshold, {"AboveThreshold"}, {"AllRows", each _, type table}, GroupKind.Local),
        
        ValueMapping = #table( type table [Index3= Number.Type, AddedValue = Number.Type], { {1, 1000}, {2, 2000}, {3, 5000} } ),
        
        fnAddValue = ( tbl as table ) as table =>
            let
                AddIndxCol = Table.AddIndexColumn( tbl, "Index2", 1, 1 ),
                MergeTables = Table.NestedJoin( AddIndxCol, {"Index2"}, ValueMapping, {"Index3"}, "JoinedTable", JoinKind.LeftOuter ),
                ExpandCol = Table.ExpandTableColumn( MergeTables, "JoinedTable", {"AddedValue"} ),
                FillDown = Table.FillDown( ExpandCol, {"AddedValue"})
            in
                Table.SelectColumns(FillDown, {"Index", "Value", "Threshold", "AddedValue"} ),
        
        ModifyTableCell = Table.AddColumn( 
                                    Grouping, 
                                    "AddValue", 
                                    each 
                                        if 
                                            [AboveThreshold] = true 
                                         then 
                                            fnAddValue( [AllRows] ) 
                                        else 
                                            Table.SelectColumns( [AllRows], {"Index", "Value", "Threshold"} ),
                                    type table ),
                                    
        ExpandedAddValue = Table.ExpandTableColumn(
                                ModifyTableCell, 
                                "AddValue", 
                                {"Index", "Value", "Threshold", "AddedValue"}
                          ),
        RemovedOtherColumns = Table.SelectColumns(
                                                 ExpandedAddValue,
                                                 {"Index", "Value", "Threshold", "AddedValue"}),
                                                 
        ChangedType2 = Table.TransformColumnTypes(
                                RemovedOtherColumns,
                                {
                                    {"Index", Int64.Type}, 
                                    {"Value", type number}, 
                                    {"Threshold", type number}, 
                                    {"AddedValue", Int64.Type}
                                }
                            )
    in
        ChangedType2
    • pontushaglund's avatar
      pontushaglund
      Helper I

      Really impressive but I have to take a few hours to try to wrap my head around what it is you've done. I like it a lot!

  • hi pontushaglund,

     

    I think, as you mentioned, merging to the preceeding two rows would be the best way.

     

     

     

    let
        Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMlTSUTI0MACSlgZKsTrRSkYgASMkAWOQgCmSgAmQaYHEN0U3wgwkYIgkYI5uhAVIwARJwBJsBoIPZqNoMQS71AxZBOxUuEtiAQ==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type text) meta [Serialized.Text = true]) in type table [Index = _t, Value = _t, Threshold = _t]),
        #"Changed Type" = Table.TransformColumnTypes(Source,{{"Index", Int64.Type}, {"Value", Int64.Type}, {"Threshold", Int64.Type}}),
        #"Added Custom" = Table.AddColumn(#"Changed Type", "Above Threshold", each if [Value] > [Threshold] then "TRUE" else "FALSE"),
        #"Changed Type1" = Table.TransformColumnTypes(#"Added Custom",{{"Above Threshold", type logical}}),
        #"Added Index" = Table.AddIndexColumn(#"Changed Type1", "Index.1", 0, 1),
        #"Renamed Columns" = Table.RenameColumns(#"Added Index",{{"Index.1", "Previous"}}),
        #"Merged Queries" = Table.NestedJoin(#"Renamed Columns",{"Previous"},#"Renamed Columns",{"Index"},"Renamed Columns",JoinKind.LeftOuter),
        #"Expanded {0}" = Table.ExpandTableColumn(#"Merged Queries", "Renamed Columns", {"Above Threshold"}, {"Renamed Columns.Above Threshold"}),
        #"Renamed Columns1" = Table.RenameColumns(#"Expanded {0}",{{"Renamed Columns.Above Threshold", "Prev.Above Threshold"}}),
        #"Added Custom1" = Table.AddColumn(#"Renamed Columns1", "Benutzerdefiniert", each [Previous]-1),
        #"Renamed Columns3" = Table.RenameColumns(#"Added Custom1",{{"Benutzerdefiniert", "PrevPrev"}}),
        #"Merged Queries1" = Table.NestedJoin(#"Renamed Columns3",{"PrevPrev"},#"Renamed Columns3",{"Index"},"Added Custom1",JoinKind.LeftOuter),
        #"Expanded {0}1" = Table.ExpandTableColumn(#"Merged Queries1", "Added Custom1", {"Above Threshold"}, {"Added Custom1.Above Threshold"}),
        #"Renamed Columns2" = Table.RenameColumns(#"Expanded {0}1",{{"Added Custom1.Above Threshold", "prevPrev.Above Threshold"}}),
        #"Sorted Rows" = Table.Sort(#"Renamed Columns2",{{"Index", Order.Ascending}}),
        #"Added Custom2" = Table.AddColumn(#"Sorted Rows", "penalty", each if  [Above Threshold] then 
       if [Prev.Above Threshold] <> null and [Prev.Above Threshold] then
         if [prevPrev.Above Threshold] <> null and [prevPrev.Above Threshold] then
           5000
         else
           2000
       else
          1000
     else
    0)
    in
        #"Added Custom2"

     

     

     

    regards

     

    florian