Write a python code that Remove duplicates from a list with explanation.

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Khushi Singh · Answer

When working with lists in Python, you may encounter duplicate elements. Removing these duplicates ensures each item appears only once. A simple and efficient way to remove duplicates is by converting the list into a set, as sets in Python automatically store only unique elements. However, using a set does not preserve the original order of the list.

If maintaining the original order is important, you can use a different approach by iterating through the list, checking if an element has already been seen, and adding it to a new list if it has not. This way, the first occurrence of each element is retained, and duplicates are ignored.

Here’s how both concepts work:

Set approach: Quick, but does not guarantee order.
Manual checking with a loop: Slightly slower, but maintains the input order.

Depending on your requirements (whether you need to maintain the original order or not), you can pick either method.

Below is a Python code example that removes duplicates from a list while maintaining the order. It uses a set to track seen elements and a new_list to store results.

def remove_duplicates(lst):
   seen = set()
   unique_list = []
   for item in lst:
       if item not in seen:
           unique_list.append(item)
           seen.add(item)
   return unique_list
# Example usage
original_list = [1, 2, 2, 3, 4, 4, 5, 1, 6]
result = remove_duplicates(original_list)
print("Original List:", original_list)
print("List after removing duplicates:", result)

Explanation of Code:

seen keeps track of elements that have already appeared.
Only unseen elements are added to unique_list.
This ensures the first occurrence is kept and duplicates are ignored.

The output for the above example will be:

Original List: [1, 2, 2, 3, 4, 4, 5, 1, 6]
List after removing duplicates: [1, 2, 3, 4, 5, 6]

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Write a python code that Remove duplicates from a list with explanation.

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