Remove Duplicates From a List

Sebastian Witowski
4 min readOct 22, 2020

How do we remove duplicates from a list? One way is to go through the original list, pick up unique values, and append them to a new list.

Let’s prepare a simple test. I will use the randrange to generate 1 million random numbers between 0 and 99 (this will guarantee some duplicates):


from random import randrange

DUPLICATES = [randrange(100) for _ in range(1_000_000)]
Sebastian Witowski

Python consultant and freelancer at Writes about productivity, tools, Python, and programming best practices.