Replacing comma separated values to texts with creating a New column

[PowerBITesting]

Trying to create a Column with below Logic 

#"Added Custom" = Table.AddColumn(#"Changed Type", "Custom", each Text.Combine( List.ReplaceMatchingItems(Text.ToList ([CommaSeparatedNumbersColumnName]), { {100,"A" },{"200","B" },{"300","C" },{",","." } })),type text)

expected result

100,200,300 ---> A.B.C

100------------->A

100,200 --------->A,B

Note : only {",","." }  this part replaced 

[edhans]

Try this @PowerBITesting 

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMjQw0DECYmMDA6VYHTAfRkPEYgE=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Column1 = _t]),
    #"Added Custom" = 
        Table.AddColumn(
            Source, 
            "Custom", 
            each 
            Text.Combine(
                List.ReplaceMatchingItems(
                    {Text.Split([Column1], ",")}{0},
                    {{"100","A"},{"200","B"},{"300","C"}}
                ),"."
            )
        )
in
    #"Added Custom"

It generates this (NOTE: Above code properly replaces the comma with period. My screenshot below doesn't reflect that)

How to use M code provided in a blank query:
1) In Power Query, select New Source, then Blank Query
2) On the Home ribbon, select "Advanced Editor" button
3) Remove everything you see, then paste the M code I've given you in that box.
4) Press Done
5) See this article if you need help using this M code in your model.

[Greg_Deckler · Accepted solution]

@PowerBITesting - You can use SUBSTITUTE in DAX:

New Column = 
  SUBSTITUTE(
    SUBSTITUTE(
      SUBSTITUTE([Column],"100","A"),
      "200","B"
    ),
    "300","C"
  )

Should be able to do the same thing in Power Query essentially nesting your replacer functions. @ImkeF @edhans  

[amitchandak]

@PowerBITesting , if they are comma-separated number then use  Text.Split in place of Text.ToList and try

[edhans]

@amitchandak - did you try your suggestion? It just returns an error when I try that simple replacement.

[amitchandak]

@edhans , There was a formula give with the result and I assumed it working and text.Split will convert comma-separated text string and that is what suggested. Seem like that is needed too. 

[edhans]

That is why I was asking @amitchandak . If I read @PowerBITesting 's original post correctly, they were getting the column with the red (1) below, and wanted what shows up in column marked with the red (2).

But I still cannot get your solution to replace Text.ToList with Text.Split. It returns an error, and doesn't do the proper replacement of 100 with A, 200, with B, etc.

But I could be wrong. That is why I was asking if you tested it as I'd like to see your solution to better understand. I have been unable to get it to work.