Python Set difference to find lost element from a duplicated array Last Updated : 28 Jul, 2022 Comments Improve Suggest changes Like Article Like Report Given two arrays which are duplicates of each other except one element, that is one element from one of the array is missing, we need to find that missing element. Examples: Input: A = [1, 4, 5, 7, 9] B = [4, 5, 7, 9] Output: [1] 1 is missing from second array. Input: A = [2, 3, 4, 5 B = 2, 3, 4, 5, 6] Output: [6] 6 is missing from first array. We have existing solution for this problem please refer Find lost element from a duplicated array. We can solve this problem quickly in python using Set difference logic. Approach is very simple, simply convert both lists in Set and perform A-B operation where len(A)>len(B). Implementation: Python3 # Function to find lost element from a duplicate # array def lostElement(A,B): # convert lists into set A = set(A) B = set(B) # take difference of greater set with smaller if len(A) > len(B): print (list(A-B)) else: print (list(B-A)) # Driver program if __name__ == "__main__": A = [1, 4, 5, 7, 9] B = [4, 5, 7, 9] lostElement(A,B) Output[1] Comment More infoAdvertise with us Next Article Python Set difference to find lost element from a duplicated array S Shashank Mishra Follow Improve Article Tags : Python DSA Arrays python-set Practice Tags : Arrayspythonpython-set Similar Reads Find lost element from a duplicated array Given two arrays that are duplicates of each other except one element, that is one element from one of the array is missing, we need to find that missing element. Examples: Input: arr1[] = {1, 4, 5, 7, 9} arr2[] = {4, 5, 7, 9}Output: 11 is missing from second array.Input: arr1[] = {2, 3, 4, 5} arr2[ 15+ min read Javascript Program for Find lost element from a duplicated array Given two arrays that are duplicates of each other except one element, that is one element from one of the array is missing, we need to find that missing element.Examples: Input: arr1[] = {1, 4, 5, 7, 9} arr2[] = {4, 5, 7, 9}Output: 11 is missing from second array.Input: arr1[] = {2, 3, 4, 5} arr2[] 4 min read Find missing elements from an Array with duplicates Given an array arr[] of size N having integers in the range [1, N] with some of the elements missing. The task is to find the missing elements. Note: There can be duplicates in the array. Examples: Input: arr[] = {1, 3, 3, 3, 5}, N = 5Output: 2 4Explanation: The numbers missing from the list are 2 a 12 min read How to Remove Duplicate Elements from NumPy Array In this article, we will see how to remove duplicate elements from NumPy Array. Here we will learn how to Remove Duplicate Elements from a 1-D NumPy Array and 2-D NumPy Array.Input1: [1 2 3 4 5 1 2 3 1 2 9] Output1: [1 2 3 4 5 9] Explanation: In this example, we have removed duplicate elements from 7 min read Count distinct elements in an array in Python Given an unsorted array, count all distinct elements in it. Examples: Input : arr[] = {10, 20, 20, 10, 30, 10} Output : 3 Input : arr[] = {10, 20, 20, 10, 20} Output : 2 We have existing solution for this article. We can solve this problem in Python3 using Counter method. Approach#1: Using Set() Thi 2 min read Python - Check if list contains all unique elements To check if a list contains all unique elements in Python, we can compare the length of the list with the length of a set created from the list. A set automatically removes duplicates, so if the lengths match, the list contains all unique elements. Python provides several ways to check if all elemen 2 min read Ways to remove duplicates from list in Python In this article, we'll learn several ways to remove duplicates from a list in Python. The simplest way to remove duplicates is by converting a list to a set.Using set()We can use set() to remove duplicates from the list. However, this approach does not preserve the original order.Pythona = [1, 2, 2, 2 min read Program to print duplicates from a list of integers in Python In this article, we will explore various methods to print duplicates from a list of integers in Python. The simplest way to do is by using a set.Using SetSet in Python only stores unique elements. So, we loop through the list and check if the current element already exist (duplicate) in the set, if 2 min read Find index of an extra element present in one sorted array Given two sorted arrays. There is only 1 difference between the arrays. The first array has one element extra added in between. Find the index of the extra element. Examples: Input: {2, 4, 6, 8, 9, 10, 12}; {2, 4, 6, 8, 10, 12}; Output: 4 Explanation: The first array has an extra element 9. The extr 15+ min read Python | Pandas Index.difference() Python is a great language for doing data analysis, primarily because of the fantastic ecosystem of data-centric python packages. Pandas is one of those packages and makes importing and analyzing data much easier.Pandas Index.difference() function return a new Index with elements from the index that 2 min read Like