Power Query 'scoping' i think

[Dicken]

Hello I have come across this in a few situations where grouping or working with nested let statements 
in these three example the first does not work, the other two , where i have a variable or a named function do, 
I wondered if anyone can give me more information or a link to a blog or  something on this subject, 
Just interested generally; 

 Table.Group( Source , {"Name"}, {{"Count", each 
 let 
 acc = List.Generate( ()=> [ x = 0 , y = [Unit] {0} ] , 
 each [x] < List.Count( [Unit]   ) , 
 each [ x = [x] + 1, y = [y] + [Unit]  {x} ] , 
 each [y] )
 in acc }} )  = [Unit] not found, 


= Table.Group( Source , {"Name"}, {{"Count", each 
 let unt = [Unit] , 
 acc = List.Generate( ()=> [ x = 0 , y = unt {0} ] , 
 each [x] < List.Count( unt  ) , 
 each [ x = [x] + 1, y = [y] + unt {x} ] , 
 each [y] )
 in acc }} 


= Table.Group( Source , {"Name"}, {{"Count", (z)=> 
 let 
 acc = List.Generate( ()=> [ x = 0 , y = z[Unit] {0} ] , 
 each [x] < List.Count( z[Unit]   ) , 
 each [ x = [x] + 1, y = [y] + z[Unit]  {x} ] , 
 each [y] ) 
in acc }} )

[Shai_Karmani · Accepted solution]

When you use each inside List.Generate, _ refers to the state record, not the group table. That’s why [Unit] fails  it looks for Unit in the wrong scope. If you bind the column first (e.g., unt = t[Unit]) or pass the table explicitly ((t)=>t[Unit]), the reference resolves correctly.

Here's an interesting reference: The Each Keyword in Power Query – Excelguru

Shai Karmani | Data & Analytics

If it helped ✅ please mark as resolved & give a kudo so others can find it too.

Let’s connect on LinkedIn

[Dicken]

Thanks for the link will have a read. 

RD