Return Column name of first non null value

[orangebloss]

Potentially asking for the impossible here! I have a formula that return s the first non null value in a row - what I actually want to do is return the column name,

(List.RemoveNulls(List.RemoveFirstN(Record.ToList(_),4)))

returns the first value correctly, I tried using Table.CoumnNames but it wasn't happy!

any thoughts and suggestions appreciated

The source file is a CSV if that makes any difference

 

[JGordon11]

let
    Source = Excel.CurrentWorkbook(){[Name="Table3"]}[Content],
    tcn = Table.ColumnNames(Source),
    Result = Table.AddColumn(Source, "First Non-null Column", each 
        try
            List.Select(List.Zip({Record.ToList(_), tcn}), (x)=> x{0}<> null){0}{1}
        otherwise
            "N/A")
in
    Result

Book1
	A	B	C	D	E	F	G	H	I	J	K
1	Col1	Col2	Col3	Col4		Col1	Col2	Col3	Col4	First Non-null Column
2			29	15				29	15	Col3
3	49		1	35		49		1	35	Col1
4	36	31	2	17		36	31	2	17	Col1
5				44					44	Col4
6	32	42	33	13		32	42	33	13	Col1
7	41			18		41			18	Col1
8	14	9	47	26		14	9	47	26	Col1
9										N/A
10	12		25			12		25		Col1
11				23					23	Col4
12	30	11	34	46		30	11	34	46	Col1
13		27		51			27		51	Col2
14	16	6	3	8		16	6	3	8	Col1
15
Sheet2

 

[orangebloss]

tcn = Table.ColumnNames(Source), Result = Table.AddColumn(Source, "First Non-null Column", each try List.Select(List.Zip({Record.ToList(_), tcn}), (x)=> x{0}<> null){0}{1} otherwise "N/A")

Hi thanks for this - I'm almost there, the columns I want to look at start at column 5, can you explain the meaning of the numbers in brackets so i can try and figure this out?

Thanks