New column - If value = null, use value on previous row.

[TommyMossberg]

I got data from my source in a csv formated like this.

Got this	Got this
4001	Value
4002	Value
	Value
4003	Value
	Value
	Value
	Value
4004	Value
	Value
	Value
	Value
	Value
	Value

In order to connect it to my other data I need it like this

Got this	Want this	Got this
4001	4001	Value
4002	4002	Value
	4002	Value
4003	4003	Value
	4003	Value
	4003	Value
	4003	Value
4004	4004	Value
	4004	Value
	4004	Value
	4004	Value
	4004	Value
	4004	Value

How do I create the calculated(?) column in the example above?

Thanks in advance!

[AlB · Accepted solution]

Hi @TommyMossberg 

Just use the Fill down feature. Place the following M code in a blank query to see the steps.

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMjEwMFTSUQpLzClNVYrVAQsYoQgooEsb45HGxwNqNSFTK05eLAA=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [#"Got this" = _t, #"Got this.1" = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Got this", Int64.Type}}),
    #"Added Custom" = Table.AddColumn(#"Changed Type", "Custom", each [Got this]),
    #"Filled Down1" = Table.FillDown(#"Added Custom",{"Custom"}),
    #"Reordered Columns" = Table.ReorderColumns(#"Filled Down1",{"Got this", "Custom", "Got this.1"})
in
    #"Reordered Columns"

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