Python: Remove the duplicate elements of a given array of numbers

Last update on April 17 2025 13:01:17 (UTC/GMT +8 hours)

Remove Duplicates from Array

Write a Python program that removes duplicate elements from a given array of numbers so that each element appears only once and returns the new length of the array.

Sample Solution:

Python Code:

# Define a function to remove duplicates from a sorted list
def remove_duplicates(nums):
    # Iterate through the list in reverse order
    for i in range(len(nums)-1, 0, -1):
        # Check if the current element is equal to the previous one
        if nums[i] == nums[i-1]:
            # If equal, delete the previous element to remove the duplicate
            del nums[i-1]
    # Return the length of the modified list
    return len(nums)

# Test the function with two different lists and print the results
print(remove_duplicates([0,0,1,1,2,2,3,3,4,4,4]))  # [0, 1, 2, 3, 4], Length: 5
print(remove_duplicates([1, 2, 2, 3, 4, 4]))        # [1, 2, 3, 4], Length: 4

Sample Output:

5
4

Explanation:

Here is a breakdown of the above Python code:

First the function "remove_duplicates" takes a sorted list (nums) as input.
It iterates through the list in reverse order using a 'for' loop.
Inside the loop, it compares each element with its previous one to identify duplicates.
If a duplicate is found, it deletes the previous element using 'del' to remove the duplicate.
The function returns the length of the modified list after removing duplicates.
Test the function with two different lists and print the modified lists along with their lengths.

Visual Presentation:

Python: Remove the duplicate elements of a given array of numbers

Flowchart:

For more Practice: Solve these Related Problems:

Write a Python program to remove duplicate integers from an array using a set and return the new length.
Write a Python program to eliminate duplicates from a list in-place and output the updated array length.
Write a Python program to filter out duplicate values from a list while preserving the original order.
Write a Python program to create a new array containing only the unique elements from an input list.

Go to:

Previous: Write a Python program to check whether a given integer is a palindrome or not.
Next: Write a Python program to calculate the maximum profit from selling and buying values of stock.

Python Code Editor:

Have another way to solve this solution? Contribute your code (and comments) through Disqus.