List.IsDistinct Function in Power Query

The List.IsDistinct function returns a logical value whether there are duplicates in the list; true if the list is distinct i.e., no duplicates, false if there are duplicate values.

Syntax

Example: Check the list is distinct or not.

Power Query M

let
  source = {"India", "America", "Canada", null, "Australia", "England", "null"}, 
  return = List.IsDistinct(source)
in
  return   

The output of the above code is true, as null and “null” are two different values.

Example: The function is case sensitive.

Power Query M

let
  source = {"India", "America", "Canada", null, "Australia", "England", "null", "australia"}, 
  return = List.IsDistinct(source)
in
  return    

The output of the above code is true, as by default the function is case sensitive so it will consider Australia and australia are two different values.

Example: Case In-Sensitivity.

Power Query M

let
  source = {"India", "America", "Canada", null, "Australia", "England", "null", "australia"}, 
  return = List.IsDistinct(source, Comparer.OrdinalIgnoreCase)
in
  return    

The output of the above code is false. By using Comparer.OrdinalIgnoreCase we make the function case insensitive, so now the function will consider Australia and australia are same values.