Duplicate elements in an array can cause serious issues in programming, as they can skew the results and impact the overall efficiency of the code. In Java, there are several ways to remove duplicate elements from an array, but not all methods are efficient and easy to implement. In this article, we will explore the best way to remove duplicates in an array in Java.
Before we dive into the solution, let's first understand why duplicates occur in an array. An array is a data structure that stores a collection of elements of the same data type. When we add elements to an array, we can accidentally add the same element multiple times, resulting in duplicates. These duplicates can cause problems when we perform operations on the array, such as searching or sorting.
Now, let's look at the best way to remove duplicates in an array in Java. The most efficient way to remove duplicates is by using the HashSet data structure. HashSet is a collection that stores unique elements, which means it automatically removes any duplicates. Here's how we can use it to remove duplicates from an array:
1. Create a HashSet object of the same data type as the array. For example, if our array contains integers, we will create a HashSet of integers.
2. Loop through the array and add each element to the HashSet using the add() method.
3. Since HashSet doesn't allow duplicates, any duplicate elements in the array will not be added to the HashSet.
4. Once all the elements have been added, we can convert the HashSet back to an array using the toArray() method.
Let's see this in action with an example code:
```
// creating an array with duplicate elements
int[] arr = {1, 2, 3, 4, 2, 4, 5, 1};
// creating a HashSet of integers
HashSet<Integer> set = new HashSet<>();
// looping through the array and adding elements to the HashSet
for (int i = 0; i < arr.length; i++) {
set.add(arr[i]);
}
// converting the HashSet back to an array
int[] newArr = set.toArray(new int[set.size()]);
// printing the new array without duplicates
for (int i = 0; i < newArr.length; i++) {
System.out.print(newArr[i] + " ");
}
// Output: 1 2 3 4 5
```
As you can see, the duplicate elements 2 and 4 have been removed from the array using the HashSet. This method not only removes duplicates efficiently, but it also preserves the order of the elements in the array.
Another way to remove duplicates in an array is by using the Arrays class's utility method called `stream().distinct().toArray()`. This method creates a stream of elements and uses the distinct() method to remove duplicates before converting it back to an array. Here's how we can use it:
```
// creating an array with duplicate elements
int[] arr = {1, 2, 3, 4, 2, 4, 5, 1};
// converting the array to a stream and removing duplicates
int[] newArr = Arrays.stream(arr).distinct().toArray();
// printing the new array without duplicates
for (int i = 0; i < newArr.length; i++) {
