Forum Discussion
Power Query 'scoping' i think
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 }} )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.
2 Replies
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.
Thanks for the link will have a read.
RD
