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1. Sum of List Elements2. Largest Element in List3. Smallest Element in List4. Count Occurrences in List5. Remove Duplicates from List6. Merge Two Lists7. Intersection of Lists8. Union of Lists9. Sort List10. Reverse List11. Check if List is Sorted12. Find Second Largest Element13. Find N Largest Elements14. Clone / Copy List15. Rotate List16. Remove Empty Lists17. Flatten Nested List18. Find Common Elements of Two Lists19. List Slicing Programs20. Replace List Elements21. Remove Element by Value22. Count Prime Numbers in List23. Pair Sum Problem24. Unique Elements from Both Lists25. List Difference

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
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.

After this program

If the idea is still fuzzy, read Day 5: Lists and List Methods in the Python course. For a short check, try the Python quiz (300 questions). Stay with all 25 list programs, or see every topic on Python exercises.

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