Python Program to Remove Duplicates from a List

This post shows how to remove duplicate elements from a list in Python, while preserving the original order of elements.

Remove duplicates from a list in Python:

Explanation:
A simple way to deduplicate while keeping order is to walk through the list and add each element to a result list only if it hasn't been seen before, tracked using a set for fast lookups.

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Python Program to Remove Duplicates from a List

numbers = [10, 20, 10, 30, 20, 40, 50, 30]
seen = set()
result = []

for num in numbers:
    if num not in seen:
        seen.add(num)
        result.append(num)

print(f"List after removing duplicates: {result}")

Output:

List after removing duplicates: [10, 20, 30, 40, 50]

If order doesn't matter, list(set(numbers)) is a shorter way to do this — see more list-based problems in our Interview Prep section.

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