It is well understood that arrays serve a crucial role in holding data in a sequential manner within memory. However, there are instances where we might inadvertently store identical or duplicate values within an array. Consequently, it becomes necessary to eliminate these duplicate entries. To achieve this, there are various techniques available that allow us to remove elements from the array.
In this segment, we will explore those techniques and gain a clearer understanding through the accompanying examples.
In general, developers often seek to enhance both the accuracy and efficiency of their code. To achieve this, it is essential to eliminate any duplicate elements present within an array. Consequently, there are various techniques available that can assist in the removal of duplicate values from arrays.
Now, let us proceed to explore each of those methods individually.
Using the filter method
The filter function serves the purpose of retrieving duplicate values from an array. This method generates a new array comprising elements that meet a defined condition. If any element does not satisfy this condition or evaluates to false, it will be excluded from the resulting filtered array.
We will create an example that demonstrates how to exclude certain values from an array by utilizing the filter method. The illustration is provided below:
<script>
var array=["x","w","d","w","x"];
function filterDuplicates(new_array){
return new_array.filter((value,index) =>new_array.indexOf(value)===index);
}
console.log(filterDuplicates(array));
</script>
Output:
Using Set method
The Set function is an alternative method that allows for the creation of a new Set, which can be described as a collection designed to hold unique values derived from a specified array. The following is a fundamental code example demonstrating the implementation of the Set function:
<script>
var array=["a","a","d","c","d"];
function setDuplicates(new_array){
return [...new Set(new_array)]
}
console.log(setDuplicates(array));
</script>
Output:
Using the reduce method
The reduce function is a method designed to process the elements of an array and subsequently amalgamate those values or elements into a final array, guided by the reducer function that we define.
Below is a code implementation designed to minimize the elements within the array:
<script>
var array=["you","me","I","you","me","I"];
function reduceDuplicates(new_array){
let collect=new_array.reduce(function (a,b){
if(a.indexOf(b)<0) a.push(b);
return a;
},[]);
return collect;
}
console.log(reduceDuplicates(array));
</script>
Output:
Using forEach and includes method
The includes function is designed to return false when an element is absent from the specified array, and it returns true if the element exists within the array. Meanwhile, the forEach method serves as a loop that enables us to traverse through the values contained in the array.
Here is a sample code that illustrates how these techniques function to eliminate duplicate entries from an array:
<script>
var array=["John","Merry","Ada","Merry","Michael"];
function duplicates(new_array){
let collect=[];
new_array.forEach(value=>{
if(!collect.includes(value))
{
collect.push(value)
}
});
return collect;
}
console.log(duplicates(array));
</script>
Output:
Using indexOf and push methods
The indexOf function, when combined with the push function, can be utilized to eliminate duplicate entries from an array and retrieve all the distinct elements contained within it.
Here is an illustrative code snippet that will assist you in comprehending how the indexOf function operates in conjunction with the push function:
<script>
var array = ["red","yellow","blue","black","blue"];
function duplicates(new_array){
var collect = [];
for(i=0; i < new_array.length; i++){
if(collect.indexOf(new_array[i]) === -1) {
collect.push(new_array[i]);
}
}
return collect;
}
console.log(duplicates(array));
</script>
Output:
By employing the aforementioned techniques, we can effectively identify and eliminate duplicate elements found within the array.
However, when it comes to eliminating duplicate objects from an array, it is essential to utilize the property name of the objects within that array. Just like individual elements, these objects can also appear multiple times within the array, leading to redundancy that needs to be addressed.
To eliminate duplicate objects from the specified array, you can utilize the code provided below:
<script>
function removeDuplicates(new_array){
var collect = [];
for(var value of new_array){
if(collect.indexOf(value) === -1){
collect.push(value);
}
}
return collect;
}
var colors = ["green","black","black"];
console.log(removeDuplicates(colors));
</script>
Output:
Typically, the process of removing duplicate values is essential when engaging in any project, particularly in software development. Developers often require this approach because every client demands software or applications that are not only optimized and tailored to their needs but also user-friendly and compatible. This ensures that the overall value of the organization can be enhanced.
Here are several techniques that developers can employ when undertaking projects that utilize JavaScript.