7 – Unique elements from a list

7 – Unique elements from a list#

The built-in type set can be used if you need to compute the unique values from an iterable, like a list.

Because sets are unordered, the result will contain the unique values in an arbitrary order.

nums = [42, 73, 42, 42, 0, 73, 10, 10, 16]
for unique_num in set(nums):
    print(unique_num, end=" ")
# 0 73 42 10 16

If the order is important and you’re running Python 3.8 or later, you can use dict.fromkeys instead:

nums = [42, 73, 42, 42, 0, 73, 10, 10, 16]
for unique_num in dict.fromkeys(nums):
    print(unique_num, end=" ")
# 0 73 42 10 16

These two options are very efficient and only work with hashable values.