# Basic syntax:

len(set(my_list))

# By definition, sets only contain unique elements, so when the list

# is converted to a set all duplicates are removed. 

​

# Example usage:

my_list = ['so', 'so', 'so', 'many', 'duplicated', 'words']

len(set(my_list))

--> 4

​

# Note, list(set(my_list)) is a useful way to return a list containing

#   only the unique elements in my_list

from collections import Counter

​

words = ['a', 'b', 'c', 'a']

​

Counter(words).keys() # equals to list(set(words))

Counter(words).values() # counts the elements' frequency

len(set(["word1", "word1", "word2", "word3"]))

# set is like a list but it removes duplicates

# len counts the number of things inside the set