Array Replace JavaScript

What is an Array in JavaScript?

In JavaScript, an array is an object that contains a collection of data types that is similar to each other. In simple words, an array is a collection of similar data types that is used to store the values or elements.

In JavaScript, Array helps us to organize the data that is similar to each other and store it. With the help of an array, we can call value using an index instead of assigning or calling properties. In Array, the index tells the location of a value that is stored in memory.

How to Replace an Element from an Array in JavaScript?

In JavaScript, replacing an element in an array means updating the value of the current array at a specified index within the array with a new value. We can effectively modify the element of the array with the use of different methods.

Some methods are as follows:

Using the Array indexof () method

The array indexof () method in JavaScript is used to find the value that is given within the array. After that, we can use the index to replace the new value to that index.

In simple words, the array indexof () method is used to find the index of the given value in an array and replace it with the new value. Basically, in this method, we use indexing and assignment operators to replace the value from an array.

Example

Let's take a simple example to understand how does array indexof () works:

Output:

Using the splice () method

In JavaScript, the splice () method is used to replace the elements of an existing array either by removing the element or replacing the elements at the index that we desired.

The Splice () method modifies the existing array to replace the element within the array. It can replace, add, or remove the element from an array.

Syntax

Example

Output:

Using the slice () method

The slice () method in JavaScript, will select some portion of an array and it will return a copy of it more like a shallow copy. The slice () method does not change the original array.

In simple words, we have two arguments in the slice method (). The first one is based on a zero index which is known as the start argument which helps us to start selecting a portion of the array and the end argument is also a zero-based index which helps us to stop selecting the portion of the array.

Syntax

Example

Output:

Using array map () and filter () methods

In JavaScript, the map () method is used to transform array elements and with the use of a filter () to select include elements based on a condition, that helps us to create a new array with modified or filtered values.

Syntax

Example

Let's take a simple program to understand how map () and filter () works:

Output:

Advantages of using Array in JavaScript

Efficient Access

In JavaScript, an array offers us constant time so we can access the elements and retrieve an element by its index quickly. With the help of an array, we can do tasks where element access is frequently required.

Memory Efficiency

In JavaScript, an array also helps us to allocate memory in a block which minimizes the memory overhead and we can reduce the need for additional data structure to store data.

Data Manipulation

In an array in JavaScript, we have built-in functions that help us in data manipulation like adding, removing, and sorting elements effectively and efficiently.

Array Methods

In JavaScript, an array provides us with various methods like map (), filter (), reduce (), and many more. In other words, arrays help us to simplify the complex data operations.

Iteration Support

In JavaScript, an array is supported by easy iteration with the use of loops which makes it convenient to process all elements sequentially.

Limitations of using Array in JavaScript

Fixed Size

In JavaScript, the array size is fixed. In an array once the size is declared then it cannot be changed.

Lack of flexibility

In JavaScript, array is not flexible as they are fixed in size.

Wasted Space

In JavaScript, array may waste some space if not all the element are in the collection are used.