Power Query Transform data within Group/Buckets - grouping

Question

I want to transform a column in Power query. Only the transformation should be applied within the group based on a condition. This is my data.
Here in the above table, I just want to transform Office based column to all 1 if any Office-based column is set to 1 on the particular ID group. But all the Office based column value is 0 on the particular ID group, it should not transform the column.
My expected result would be,
It would be fine, If an additional column can have the transformed column.

Answer 1

try this
let Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
#"Changed Type" = Table.TransformColumnTypes(Source,{{"ID", type text}, {"Item", type text}, {"Home Based", Int64.Type}, {"Office Based", Int64.Type}, {"Amount", Int64.Type}}),
// find all IDs with 1 in Office Based
#"Filtered Rows" = Table.SelectRows(#"Changed Type", each ([Office Based] = 1)),
#"Removed Other Columns" = Table.SelectColumns(#"Filtered Rows",{"ID"}),
#"Removed Duplicates" = Table.Distinct(#"Removed Other Columns"),
//merge that back in
#"Merged Queries" = Table.NestedJoin(#"Changed Type", {"ID"}, #"Removed Duplicates", {"ID"}, "Table2", JoinKind.LeftOuter),
#"Expanded Table2" = Table.ExpandTableColumn(#"Merged Queries", "Table2", {"ID"}, {"ID.1"}),
// if there was a match convert to 1 otherwise take original number
#"Added Custom" = Table.AddColumn(#"Expanded Table2", "OfficeBased2", each try if Text.Length([ID.1])>0 then 1 else [Office Based] otherwise [Office Based]),
#"Removed Columns" = Table.RemoveColumns(#"Added Custom",{"Office Based", "ID.1"}),
#"Renamed Columns" = Table.RenameColumns(#"Removed Columns",{{"OfficeBased2", "OfficeBased"}})
in #"Renamed Columns"
or the more compact version:
let Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
#"Added Custom" = Table.AddColumn(Source,"Custom",(i)=>Table.SelectRows(Source, each [ID]=i[ID]) [Office Based]),
#"Added Custom1" = Table.AddColumn(#"Added Custom", "Office Based2", each if List.Contains([Custom],1) then 1 else [Office Based]),
#"Removed Columns" = Table.RemoveColumns(#"Added Custom1",{"Custom", "Office Based"})
in #"Removed Columns"
The first method probably works best for large data sets

Answer 2

Here's another method:
Group by ID
Apply the Table.TransformColumns operation to each subtable
Then re-expand
let
Source = Excel.CurrentWorkbook(){[Name="Table2"]}[Content],
#"Changed Type" = Table.TransformColumnTypes(Source,{{"ID", type text}, {"Item", type text}, {"Home Based", Int64.Type}, {"Office Based", Int64.Type}, {"Amount", Int64.Type}}),
#"Grouped Rows" = Table.Group(#"Changed Type", {"ID"}, {
{"Xform", (t)=>Table.TransformColumns(t, {
{"Office Based", each if List.ContainsAny(t[Office Based],{1}) then 1 else 0}}) ,
type table
[ID=nullable text, Item=nullable text, Home Based=nullable number, Office Based=nullable number, Amount=nullable number]}
}),
#"Expanded Xform" = Table.ExpandTableColumn(#"Grouped Rows", "Xform",
{"Item", "Home Based", "Office Based", "Amount"},
{"Item", "Home Based", "Office Based", "Amount"})
in
#"Expanded Xform"