Error 'Append' is not a member of 'System.Array'

[Swara_Soni (Swara)]

@NIVED_NAMBIAR
The linq query is explained in the topic i am sharing below:

From input file Group rows having duplicate rows and update master according to master data

In the excel attached Find.xlsx (15.2 KB) , it contains 3 sheets “Input”, “Master” and “output” Input [image] Master [image] Output [image] The logic works like: In “Criteria” = “RD” , Group columns AB,AC,AD,AE,AF After grouping if the string has found duplicate rows then assign 1st row according to master and rest as “go” if string is unique then assign value according to master sheet In “Criteria” = “DD”, Group columns AB,AC,AD,AE,AF After grouping if the string has found dup…

The .xaml file is shared by @ppr in the solution.