language M substring ? in data query

Hi,

In my json input file I have a very large column (data_found in my request) and it is very long to load data in PowerBI.

I just want an extract of this large columns (the first 100 characters for example).

In the advanced editor, is it possible to add M language instructions to do that ?

Thanks

Dominique

let
    Source = Json.Document(File.Contents("C:\carto\results.json")),
    phone = Source[phone_number],
    columns = phone[columns],
    #"Converted to Table" = Table.FromList(columns, Splitter.SplitByNothing(), 1, null, ExtraValues.Error),
    #"Expanded Column1" = Table.ExpandRecordColumn(#"Converted to Table", "Column1", {"location", "numbers_of_rows_analyzed", "percentage_of_personnal_data", "data_found"}, {"location", "numbers_of_rows_analyzed", "percentage_of_personnal_data", "data_found"}),
    #"Changed Type" = Table.TransformColumnTypes(#"Expanded Column1",{{"data_found", type text}})
in
    #"Changed Type"