How to unstack a column into table using referncing index + pivot the table

Hi lcy0328

Place the following M code in a blank query to see the steps:

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WUorViVbyMYRQRhDKGEKZQChTMAVVB1MIpY2htIkhiiK4KrgyuDo0hQiVCKUItVCWKZgVCwA=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Col1 = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Col1", type text}}),
    #"Replaced Value" = Table.ReplaceValue(#"Changed Type","",null,Replacer.ReplaceValue,{"Col1"}),
    list0_ = #"Replaced Value"[Col1],
    list1_ = if List.Last(list0_)<>null then list0_&{null} else list0_ = null, //Make sure list finishes with a null to make things easier in the next step   
    list2_ = if List.First(list1_)=null then List.LastN(list1_,List.Count(list1_)-1) else list1_,
    list3_ = List.Accumulate(list2_,[total={}, partial={}],(s,c)=> if c<>null then [total=s[total], partial=s[partial]&{c}] else [total=s[total]&{s[partial]}, partial={}]),
    total = list3_[total],
    #"Converted to Table" = Table.FromList(total, Splitter.SplitByNothing(), null, null, ExtraValues.Error),
    #"Added Custom" = Table.AddColumn(#"Converted to Table", "Custom", each Text.Combine([Column1],"|")),
    #"Split Column by Delimiter" = Table.SplitColumn(#"Added Custom", "Custom", Splitter.SplitTextByDelimiter("|", QuoteStyle.Csv), {"Line1", "Line2", "Line3", "Line4", "Line5"}),
    #"Removed Columns" = Table.RemoveColumns(#"Split Column by Delimiter",{"Column1"})
in
    #"Removed Columns"

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Cheers 

Hello lcy0328 

try this approach. Uses Table.Group to split your tables on every "null", then skip and transpose every single column.

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WUorViVbyMYRQRhDKGEKZQChTMAVVB1MIpY2htIkhiiK4KrgyuDo0hQiVCKUItVCWKZgVCwA=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Col1 = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Col1", type text}}),
    #"Replaced Value" = Table.ReplaceValue(#"Changed Type","",null,Replacer.ReplaceValue,{"Col1"}),
    #"Grouped Rows" = Table.Group(#"Replaced Value", {"Col1"}, {{"AllRows", each Table.Transpose(Table.Skip(_,1)), type table [Col1=text]}}, GroupKind.Local,   (g,c)=> if c[Col1]=null then 1 else 0),
    #"Removed Other Columns" = Table.SelectColumns(#"Grouped Rows",{"AllRows"}),
    #"Expanded AllRows" = Table.ExpandTableColumn(#"Removed Other Columns", "AllRows", {"Column1","Column2","Column3","Column4","Column5"})
in
    #"Expanded AllRows"

Copy paste this code to the advanced editor in a new blank query to see how the solution works.

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Have fun

Jimmy