Search code examples
powerquerym

PowerQuery to Convert List of Records to Delimited String

Given the below JSON I'm trying to load it into Excel. The "Ratings" section I would like to format into a single delimited string/cell. I'm pretty new to PowerQuery so I'm struggling to do this. I've managed to format the list of Records to its own table, but concatenating this into a string and adding it back into my source table is where I'm drawing a blank. Any help would be appreciated.

PowerQuery

let
    Source = Json.Document(File.Contents("C:\filename.json")),
    Ratings1 = Source[Ratings],
    #"Converted to Table" = Table.FromList(Ratings1, Splitter.SplitByNothing(), null, null, ExtraValues.Error),
    LastStep = Table.ExpandRecordColumn(#"Converted to Table", "Column1", { "Source", "Value" })
in
    LastStep

JSON

{
    "Title": "Iron Man",
    "Year": "2008",
    "Rated": "PG-13",
    "Ratings": [{
            "Source": "Internet Movie Database",
            "Value": "7.9/10"
        }, {
            "Source": "Rotten Tomatoes",
            "Value": "93%"
        }, {
            "Source": "Metacritic",
            "Value": "79/100"
        }
    ]
}

Ultimately, something like below would be ideal.

enter image description here

Solution

  • How about this?

    let
    Source = Json.Document(File.Contents("C:\filename.json")),
    #"Converted to Table" = Record.ToTable(Source),
    #"Transposed Table" = Table.Transpose(#"Converted to Table"),
    #"Promoted Headers" = Table.PromoteHeaders(#"Transposed Table", [PromoteAllScalars=true]),
    #"Changed Type" = Table.TransformColumnTypes(#"Promoted Headers",{{"Title", type text}, {"Rated", type text}, {"Year", Int64.Type}}),
    #"Expanded Ratings" = Table.ExpandListColumn(#"Changed Type", "Ratings"),
    #"Expanded Ratings1" = Table.ExpandRecordColumn(#"Expanded Ratings", "Ratings", {"Source", "Value"}, {"Source", "Value"}),
    #"Added Custom" = Table.AddColumn(#"Expanded Ratings1", "Custom", each [Source] & "=" & [Value]),
    #"Grouped Rows" = Table.Group(#"Added Custom", {"Title", "Year", "Rated"}, {{"Ratings", each Text.Combine([Custom],"#(lf)"), type text}})
in
    #"Grouped Rows"

    Result

    Most of the steps here are fairly clear from their name and are produced through GUI controls. The one trickier step is where I use a custom aggregator when doing the grouping. If you use the GUI, Text.Combine is not an option in the Group By dialog box, so I selected Max (which becomes List.Max in the code) and replaced that with Text.Combine to concatenate with the line feed character as the separator.