Remove Duplicates from List in Python

Remove duplicate elements from a list while preserving order.

BeginnerList ProgramsExample 5 of 25
remove-duplicates-from-list.py
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1# Program to remove duplicates from a list while preserving order
2
3items = input("Enter list elements separated by space: ").split()
4
5seen = set()
6result = []
7for x in items:
8 if x not in seen:
9 seen.add(x)
10 result.append(x)
11
12print("List without duplicates:", result)

Output

Enter list elements separated by space: 1 2 2 3 1
List without duplicates: ['1', '2', '3']

What's going on

We track seen elements in a set and only append new items to the result list to keep the first occurrence.