Looping through rows to find the largest link

[Anonymous]

Hello everyone, need your help browsing the lines to find the longest link. Indeed, for each letter in the Parent column, I try to iterate over the Link column, to get the common letter among the links (length > 1) (here "A" for the first row) then output the largest link containing this common letter. The Output column is my expected output. I tried to create a function to get the links containing the parent letter, and another to get the longest link. But no success.

I'm still new to Power Query so thank you and sorry in advance if I ask lots of follow up questions. I am enclosing a link to the file. 

https://docs.google.com/spreadsheets/d/1NrlacnkYvXlDvpF0hhmP2QM7x9zrZYUK/edit?usp=sharing&ouid=10524... 

Many thanks,

Gop01

[v-yanjiang-msft · Accepted solution]

Hi @Anonymous ,

According to your description, here's my solution.

1. Create a custom column.

Length = Text.Length([Link])

2. Create another custom column.

Output = let 
T=Table.SelectRows(#"Added Custom1",(x)=>Text.Start(x[Link],1)=Text.Start([Link],1))
in 
Table.SelectRows(#"Added Custom1",(x)=>Text.Start(x[Link],1)=Text.Start([Link],1)and x[Length]=List.Max(T[Length]))[Link]{0}

Get the correct result:

Here's the whole M syntax:

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WclTSUXIC4oAgfxcg5eikFKsDEXVGEnUGi4JEXJDVOruAxZ3QVDs5ww0JRRIOBYuCmJ6ohnjCTYEgqCPC4AJhWPnOSBqc4WbDRSBuC0UIQez3RFGDzepYAA==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Parent = _t, Child = _t, Param = _t, Link = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Parent", type text}, {"Child", type text}, {"Param", type text}, {"Link", type text}}),
    #"Added Custom1" = Table.AddColumn(#"Changed Type", "Length", each Text.Length([Link])),
    #"Added Custom" = Table.AddColumn(#"Added Custom1", "Output", each let T=Table.SelectRows(#"Added Custom1",(x)=>Text.Start(x[Link],1)=Text.Start([Link],1))
     in 
     Table.SelectRows(#"Added Custom1",(x)=>Text.Start(x[Link],1)=Text.Start([Link],1)and x[Length]=List.Max(T[Length]))[Link]{0}),
    #"Removed Columns" = Table.RemoveColumns(#"Added Custom",{"Length"})
in
    #"Removed Columns"

I attach my sample below for your reference.

Best Regards,
Community Support Team _ kalyj

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

[Anonymous]

It works ! thank you 

[jbwtp]

hi @Anonymous,

Something like this?

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WclTSUSosKkotUorVgfAcg13g7GBHMNMJyEwsTkkrTkxJS0+DCzkGO7kgcVz8vD2cnJRiYwE=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Parent = _t, Link = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Parent", type text}, {"Link", type text}}),
    #"Grouped Rows" = Table.Group(#"Changed Type", {"Parent"}, {{"Longest", (x)=> List.First(List.Sort(List.Select(x[Link], each Text.Contains(_, x[Parent]{0})), (x,y)=> if Text.Length(x) < Text.Length (y) then 1 else 0)) }}),
    #"Merged Queries" = Table.NestedJoin(#"Changed Type", {"Parent"}, #"Grouped Rows",  {"Parent"}, "Grouped Rows", JoinKind.LeftOuter),
    #"Expanded Grouped Rows" = Table.ExpandTableColumn(#"Merged Queries", "Grouped Rows", {"Longest"}, {"Longest"})
in
    #"Expanded Grouped Rows"

[Anonymous]

not excatly but thank you for your help .