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Simplest: dump the whole collection into a Set (using the Set (Collection) constructor or Set.addAll), then see if the Set has the same size as the ArrayList. List<Integer> list = ...; Set<Integer> set = new HashSet<Integer>(list); if(set.size() < list.size()){. /* There are duplicates */. }
May 14, 2024 · In this article, we’ll learn different approaches to finding duplicates in a List in Java. Given a list of integers with duplicate elements, we’ll be finding the duplicate elements in it. For example, given the input list [1, 2, 3, 3, 4, 4, 5], the output List will be [3, 4]. 2.
Dec 11, 2018 · Approach: Get the ArrayList with duplicate values. Create another ArrayList. Traverse through the first arraylist and store the first appearance of each element into the second arraylist using contains () method. The second ArrayList contains the elements with duplicates removed. Below is the implementation of the above approach:
Here’s a Java program that demonstrates how to implement a method to find duplicate elements in an ArrayList. I’ll provide a step-by-step explanation of the logic used in the program.
Oct 15, 2008 · Java 8 streams provide a very simple way to remove duplicate elements from a list. Using the distinct method. If we have a list of cities and we want to remove duplicates from that list it can be done in a single line -. List<String> cityList = new ArrayList<>(); cityList.add("Delhi"); cityList.add("Mumbai");
Aug 25, 2021 · 5 Answers. Sorted by: 0. you can use a frequency hashmap to keep track of count, and use that map to filter out the duplicates. List<String> list = new ArrayList<>(); list.add("A"); list.add("B"); list.add("A"); list.add("B"); list.add("C"); list.add("A"); list.add("F"); list.add("Z"); list.add("C"); list.add("H");
Feb 28, 2021 · I have an ArrayList with elements, but that array list have some duplicates. Here is an example: ArrayList<CoolObject> arraylist = new ArrayList<>(); //arraylist.add(new CoolObject("In constructor, you need to put name for object")); arraylist.add(new CoolObject("1")); arraylist.add(new CoolObject("2")); arraylist.add(new CoolObject("2 ...
Java Program to Remove duplicate elements from ArrayList. To understand this example, you should have the knowledge of the following Java programming topics: Java ArrayList. Java Set Interface. Example 1: Remove duplicate elements from ArrayList using Set. import java.util.ArrayList; import java.util.Arrays; import java.util.LinkedHashSet;
To remove dupliates from ArrayList, we can convert it into Set. Since Set doesn't contain duplicate elements, it will have only unique elements. Let's see an example to remove duplicates from ArrayList: public class RemoveDuplicateArrayList {. public static void main (String [] args) {.
Learn to remove duplicate elements from an ArrayList using different techniques such as HashSet, LinkedHashSet, and using Java 8 stream.
