how to use the if loop to add new column (power M)

[Anonymous]

Dear friend,

How to use the if loop to add a new column like this info.

I want a new column looking for other columns but in the row is not null if null will look for a higher row looping like below but i don't want write long till -60

if [Column5]<> null
then [Column5]
else if #"Replaced Value" [Column5]{[Index]-1} <> null
then #"Replaced Value" [Column5]{[Index]-1}
else if #"Replaced Value" [Column5]{[Index]-2} <> null
then #"Replaced Value" [Column5]{[Index]-2}
else if #"Replaced Value" [Column5]{[Index]-3} <> null
then #"Replaced Value" [Column5]{[Index]-3}

Thank you

[amitchandak]

@Anonymous , You can use List.Select or each

new column example

let
_ind = [Index]
_Table = Table.Select(#"Replaced Value" , each [Index] <_ind)
_list = List.Select(#"Replaced Value"[Column5] , each _ <> null)
_value = if List.IsEmpty(_list) then _list{0} else null
in
_value

List.Reverse can be used in case the it in revrese order

[Anonymous]

Dear @amitchandak 

thank you may i ask for how to use this code i still don't understand let and in