Adding columns dynamically based on availability

[sendilc]

Hi, 

I have a situation where I need to add columns dynamically if the column is not available. Say for e.g. I have 4 predefined columns [A, B, C, D] and I have a table "Data" with columns [Sno, Date, B, D]. 

Now I want to iterate to check if [A,B,C,D] all predefined columns are available in table "Data", I am trying to use accumulate to find out if it can be achieved in the below fashion or is there a better way to solve this issue. 

= List.Accumulate({"A","B","C","D"}, "Data"}, Table.ColumnNames(#"Data"),
(original, current) =>

if !(Table.Hascolumns[current],original) then  

     Table.AddColumn(original,current[], each [current]))

[sendilc]

Thanks @BA_Pete this helps... I was able to solve the issue. 

[BA_Pete · Accepted solution]

Hi @sendilc ,

I'd just predefine all the columns that should be present in a blank table, then append the actual imported table onto it.

Here, Chris Webb explains it better than me:

https://blog.crossjoin.co.uk/2015/07/03/ensuring-columns-are-always-present-in-a-table-returned-by-p... 

Pete