POWERBI, DAX : concatenate strings, split, and keep substrings only once - string

Question

I try to do the following:
I have a column with strings, each can have several substrings separated by a delimiter ":"
I need to Concatenate the column strings (I do a Filter here to keep only interresting lines)
Then split according to the delimiter ":"
keep the substrings only once, if they are repeated.
Example:
ColumnHeader
AA:BB:CC
BB:DD
DD:AA:EE
EE:AA:DD:BB
BB:EE
...
Expected result would be a unique string:
"AA:BB:CC:DD:EE"
How would you do this in DAX to fill a new column ?
I expected to find for/while loops in DAX like in Python ... but failed.
I Tried this:
List =
VAR SIn = ""
VAR SOut = ""
VAR Cursor = 0
VAR SList =
CONCATENATEX(
FILTER(ATable, ATable[Name] = CTable[Name]),
[ColumnHeader],
":")
VAR pos1 = FIND(":", SList, Cursor, len(SList))
VAR pos2 = FIND(":", SList, pos1, len(SList))
VAR elem = TRIM(MID(SList, pos1+1, pos2-pos1))
// following is not good but is what I would like to do:
VAR SOut = CONCATENATE(SOut, elem)
VAR SList = MID(SList, pos2, len(SList)-pos2)
VAR Cursor = pos2
// I need to loop ... but how ? ... as no for/while loops are possibles ?
Thanks for your help.
=====================================
I manage to tackle this thanks to the answers below.
I will still give a bigger data set for a better understanding of the global problem:
I have 2 tables:
TABLE_BY_ELEMENT
KEY GROUP LIST KEY_DATA
1 G1 AA:BB:FF 11
2 G1 CC:AA 22
3 G1 FF:DD:AA 33
4 G1 CC:DD:AA 44
5 G2 CC:FF:GG 55
6 G2 BB:AA 66
TABLE_BY_GROUP
GROUP GROUP_DATA
G1 1111
G2 2222
And I want to view the data like this:
RESULT_BY_GROUP
GROUP GROUP_DATA NewList
G1 111 AA:BB:FF:CC:DD
G2 222 CC:FF:GG:BB:AA
and also:
RESULT_ELEMENT
KEY LIST KEY_DATA
1 AA:BB:FF 11
2 CC:AA 22
3 FF:DD:AA 33
4 CC:DD:AA 44
5 CC:FF:GG 55
6 BB:AA 66
I hope is is easier to understand with this.

Answer 1

This isn't something DAX is suited for well. If you need to use DAX to make it into a dynamic measure, then you'll probably need to reshape your data to be more usable. For example,
ID ColumnHeader
1 AA
1 BB
1 CC
2 BB
2 DD
3 DD
3 AA
3 EE
...
You can do this split in the query editor using the Split Column > By Delimiter tool and choosing to split on the colon and expand into rows.
Once it's in this more usable format, you can work with it in DAX like this:
List = CONCATENATEX( VALUES('Table'[ColumnHeader]), 'Table'[ColumnHeader], ":" )
Borrowing logic from here, it's possible to do this purely in DAX, but I don't recommend this route.
List =
VAR LongString =
CONCATENATEX ( VALUES ( 'Table1'[ColumnHeader] ), Table1[ColumnHeader], ":" )
VAR StringToPath =
SUBSTITUTE ( LongString, ":", "|" )
VAR PathToTable =
ADDCOLUMNS (
GENERATESERIES ( 1, LEN ( StringToPath ) ),
"Item", PATHITEM ( StringToPath, [Value] )
)
VAR GroupItems =
FILTER (
SUMMARIZE ( PathToTable, [Item] ),
NOT ISBLANK ( [Item] )
)
RETURN
CONCATENATEX ( GroupItems, [Item], ":" )

Answer 2

Let your table looks like below-
Now try this below Advance Editor code in the Power Query Editor-
let
Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WcnS0cnKycnZWitWJVgKyXFzALBcXK6CMqyuY4+oK4gCFnJxgykAysQA=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [ColumnHeader = _t]),
#"Changed Type" = Table.TransformColumnTypes(Source,{{"ColumnHeader", type text}}),
//--NEW STEPS STARTS FROM HERE
#"Added Index" = Table.AddIndexColumn(#"Changed Type", "Index", 1, 1, Int64.Type),
#"Reordered Columns" = Table.ReorderColumns(#"Added Index",{"Index", "ColumnHeader"}),
#"Split Column by Delimiter" = Table.SplitColumn(#"Reordered Columns", "ColumnHeader", Splitter.SplitTextByDelimiter(":", QuoteStyle.Csv), {"ColumnHeader.1", "ColumnHeader.2", "ColumnHeader.3", "ColumnHeader.4"}),
#"Changed Type1" = Table.TransformColumnTypes(#"Split Column by Delimiter",{{"ColumnHeader.1", type text}, {"ColumnHeader.2", type text}, {"ColumnHeader.3", type text}, {"ColumnHeader.4", type text}}),
#"Unpivoted Other Columns" = Table.UnpivotOtherColumns(#"Changed Type1", {"Index"}, "Attribute", "Value"),
#"Removed Columns" = Table.RemoveColumns(#"Unpivoted Other Columns",{"Attribute", "Index"}),
#"Removed Duplicates" = Table.Distinct(#"Removed Columns"),
#"Sorted Rows" = Table.Sort(#"Removed Duplicates",{{"Value", Order.Ascending}}),
#"Added Index1" = Table.AddIndexColumn(#"Sorted Rows", "Index", 1, 1, Int64.Type),
#"Reordered Columns1" = Table.ReorderColumns(#"Added Index1",{"Index", "Value"}),
#"Pivoted Column" = Table.Pivot(Table.TransformColumnTypes(#"Reordered Columns1", {{"Index", type text}}, "en-US"), List.Distinct(Table.TransformColumnTypes(#"Reordered Columns1", {{"Index", type text}}, "en-US")[Index]), "Index", "Value", List.Max),
#"Merged Columns" = Table.CombineColumns(#"Pivoted Column",{"1", "2", "3", "4", "5"},Combiner.CombineTextByDelimiter(":", QuoteStyle.None),"Merged")
in
#"Merged Columns"
Here is the final output-

Answer 3

Here is code from Power Query Editor considering GROUP BY-
Create a new table RESULT_BY_GROUP with this below code-
let
Source = TABLE_BY_ELEMENT,
#"Removed Columns" = Table.RemoveColumns(Source,{"KEY", "KEY_DATA"}),
#"Split Column by Delimiter" = Table.SplitColumn(#"Removed Columns", "LIST", Splitter.SplitTextByDelimiter(":", QuoteStyle.Csv), {"LIST.1", "LIST.2", "LIST.3"}),
#"Changed Type" = Table.TransformColumnTypes(#"Split Column by Delimiter",{{"LIST.1", type text}, {"LIST.2", type text}, {"LIST.3", type text}}),
#"Unpivoted Other Columns" = Table.UnpivotOtherColumns(#"Changed Type", {"GROUP"}, "Attribute", "Value"),
#"Removed Columns1" = Table.RemoveColumns(#"Unpivoted Other Columns",{"Attribute"}),
#"Removed Duplicates" = Table.Distinct(#"Removed Columns1"),
#"Sorted Rows" = Table.Sort(#"Removed Duplicates",{{"GROUP", Order.Ascending}, {"Value", Order.Ascending}}),
#"Grouped Rows" = Table.Group(#"Sorted Rows", {"GROUP"}, {{"all", each _, type table [GROUP=nullable text, Value=text]}}),
#"Added Custom" = Table.AddColumn(#"Grouped Rows", "NewList", each [all][Value]),
#"Extracted Values" = Table.TransformColumns(#"Added Custom", {"NewList", each Text.Combine(List.Transform(List.Sort(_), Text.From), ":"), type text}),
#"Removed Columns2" = Table.RemoveColumns(#"Extracted Values",{"all"}),
#"Merged Queries" = Table.NestedJoin(#"Removed Columns2", {"GROUP"}, TABLE_BY_GROUP, {"GROUP"}, "TABLE_BY_GROUP", JoinKind.LeftOuter),
#"Expanded TABLE_BY_GROUP" = Table.ExpandTableColumn(#"Merged Queries", "TABLE_BY_GROUP", {"GROUP_DATA "}, {"TABLE_BY_GROUP.GROUP_DATA "}),
#"Renamed Columns" = Table.RenameColumns(#"Expanded TABLE_BY_GROUP",{{"TABLE_BY_GROUP.GROUP_DATA ", "GROUP_DATA"}}),
#"Changed Type1" = Table.TransformColumnTypes(#"Renamed Columns",{{"GROUP", type text}, {"NewList", type text}, {"GROUP_DATA", Int64.Type}})
in
#"Changed Type1"
Here is the final output-
You can easily visualize your second requirement for table RESULT_ELEMENT using your base table TABLE_BY_ELEMENT