Getting first n unique elements from Python list

Question

I have a python list where elements can repeat.

>>> a = [1,2,2,3,3,4,5,6]

I want to get the first n unique elements from

Answer 1

Example list:

a = [1, 2, 2, 3, 3, 4, 5, 6]

Function returns all or count of unique items needed from list

1st argument - list to work with, 2nd argument (optional) - count of unique items (by default - None - it means that all unique elements will be returned)

def unique_elements(lst, number_of_elements=None):
    return list(dict.fromkeys(lst))[:number_of_elements]

Here is example how it works. List name is "a", and we need to get 2 unique elements:

print(unique_elements(a, 2))

Output: