PowerQuery in Excel - adding columns based on a List.

[Anonymous]

Hi all,

I have a question.
So Let say I have Table with any data,
then I have a list with Columns I wish to add:

{"NewCol1", "NewCol2", "NewCol3"}
the list is manualy verified (  what ccan you do? eh... )

so Now I need to add thoose columnsto MyTable.

any help would be appriciead

[Anonymous]

ok, let me provide a simple example.
Let say I have a Table:
amount in local Currency

exchange rate 2
exchange rate 3
some other columns.

and now my Column list:
NewColumnExRate1
NewColumnExRate2
NewColumnExRate2

Calculations:
if columns do not exists in original table:
NewColumnExRate1 = amount in local Currency * exchange rate 1

NewColumnExRate2 = amount in local Currency * exchange rate 2
NewColumnExRate3 = amount in local Currency * exchange rate 3

this is either / or logic,
either all of them will exists or none of them, so there will be no need to do conditional addding of columns.

I tried using @AlienSx solution but Igot defeated and could not implement addding columns with calculations, just empty ones.

[AlienSx]

@Anonymous this checks if one of column names from your list is already there. If not then all 3 columns are added

    rates = 
        [NewColumnExRate1 = each [amount in local Currency] * [exchange rate 1],
        NewColumnExRate2 = each [amount in local Currency] * [exchange rate 2],
        NewColumnExRate3 = each [amount in local Currency] * [exchange rate 3]],
    add_columns = 
        if List.Contains(Table.ColumnNames(MyTable), "NewColumnExRate3") 
        then MyTable 
        else List.Accumulate(Record.FieldNames(rates), MyTable, (s, c) => Table.AddColumn(s, c, Record.Field(rates, c)))

[wdx223_Daniel]

this code will add three null columns

=Table.SelectColumns(MyTable,Table.ColumnNames(MyTable)&{"NewCol1", "NewCol2", "NewCol3"},2)

[AlienSx]

Hi, @Anonymous 

List.Accumulate(your_list, MyTable, (s, c) => Table.AddColumn(s, c, each null))

[JoeBarry]

Hi @Anonymous 

You will need to provide more information,

What data is in the original table?

What data is in the new columns and how are they related to the original table?

Thanks

Joe