Javascript show all elements in array

JavaScript Arrays

An array is a special variable, which can hold more than one value:

Why Use Arrays?

If you have a list of items (a list of car names, for example), storing the cars in single variables could look like this:

However, what if you want to loop through the cars and find a specific one? And what if you had not 3 cars, but 300?

An array can hold many values under a single name, and you can access the values by referring to an index number.

Creating an Array

Using an array literal is the easiest way to create a JavaScript Array.

It is a common practice to declare arrays with the const keyword.

Learn more about const with arrays in the chapter: JS Array Const.

Example

Spaces and line breaks are not important. A declaration can span multiple lines:

Example

You can also create an array, and then provide the elements:

Example

Using the JavaScript Keyword new

The following example also creates an Array, and assigns values to it:

Example

The two examples above do exactly the same.

There is no need to use new Array() .

For simplicity, readability and execution speed, use the array literal method.

Accessing Array Elements

You access an array element by referring to the index number:

Note: Array indexes start with 0.

[0] is the first element. [1] is the second element.

Changing an Array Element

This statement changes the value of the first element in cars :

Example

Converting an Array to a String

The JavaScript method toString() converts an array to a string of (comma separated) array values.

Example

const fruits = [«Banana», «Orange», «Apple», «Mango»];
document.getElementById(«demo»).innerHTML = fruits.toString();

Access the Full Array

With JavaScript, the full array can be accessed by referring to the array name:

Example

Arrays are Objects

Arrays are a special type of objects. The typeof operator in JavaScript returns «object» for arrays.

But, JavaScript arrays are best described as arrays.

Arrays use numbers to access its «elements». In this example, person[0] returns John:

Array:

Objects use names to access its «members». In this example, person.firstName returns John:

Object:

Array Elements Can Be Objects

JavaScript variables can be objects. Arrays are special kinds of objects.

Because of this, you can have variables of different types in the same Array.

You can have objects in an Array. You can have functions in an Array. You can have arrays in an Array:

Array Properties and Methods

The real strength of JavaScript arrays are the built-in array properties and methods:

Array methods are covered in the next chapters.

The length Property

The length property of an array returns the length of an array (the number of array elements).

Example

The length property is always one more than the highest array index.

Accessing the First Array Element

Example

Accessing the Last Array Element

Example

Looping Array Elements

One way to loop through an array, is using a for loop:

Example

const fruits = [«Banana», «Orange», «Apple», «Mango»];
let fLen = fruits.length;

You can also use the Array.forEach() function:

Example

const fruits = [«Banana», «Orange», «Apple», «Mango»];

Adding Array Elements

The easiest way to add a new element to an array is using the push() method:

Example

const fruits = [«Banana», «Orange», «Apple»];
fruits.push(«Lemon»); // Adds a new element (Lemon) to fruits

New element can also be added to an array using the length property:

Example

const fruits = [«Banana», «Orange», «Apple»];
fruits[fruits.length] = «Lemon»; // Adds «Lemon» to fruits

Adding elements with high indexes can create undefined «holes» in an array:

Example

const fruits = [«Banana», «Orange», «Apple»];
fruits[6] = «Lemon»; // Creates undefined «holes» in fruits

Associative Arrays

Many programming languages support arrays with named indexes.

Arrays with named indexes are called associative arrays (or hashes).

JavaScript does not support arrays with named indexes.

In JavaScript, arrays always use numbered indexes.

Example

const person = [];
person[0] = «John»;
person[1] = «Doe»;
person[2] = 46;
person.length; // Will return 3
person[0]; // Will return «John»

WARNING !!
If you use named indexes, JavaScript will redefine the array to an object.

After that, some array methods and properties will produce incorrect results.

Example:

const person = [];
person[«firstName»] = «John»;
person[«lastName»] = «Doe»;
person[«age»] = 46;
person.length; // Will return 0
person[0]; // Will return undefined

The Difference Between Arrays and Objects

In JavaScript, arrays use numbered indexes.

In JavaScript, objects use named indexes.

Arrays are a special kind of objects, with numbered indexes.

When to Use Arrays. When to use Objects.

• JavaScript does not support associative arrays.
• You should use objects when you want the element names to be strings (text).
• You should use arrays when you want the element names to be numbers.

JavaScript new Array()

JavaScript has a built-in array constructor new Array() .

But you can safely use [] instead.

These two different statements both create a new empty array named points:

These two different statements both create a new array containing 6 numbers:

The new keyword can produce some unexpected results:

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Displaying all elements of an array

We used one for loop to display all elements of an array by using their index. To identify how many loops we have to make we must know the total number of elements present inside the array. That we can find out like this

So this number we will set as upper limit of our number of rotation or looping.

You can check our tutorial on creating array to create an array and now we will try to display each element of the array. Here is the code.

var scripts = new Array(); scripts[0] = "PHP"; scripts[1] = "ASP"; scripts[2] = "JavaScript"; scripts[3] = "HTML"; for (i=0;i"); >

The for loop in the above code loops through the elements of the array and display one by one vertically by adding one line break at the end of each element. The upper limit of the for loop is set to script.length value which is in this case equal to 4

Using toString()

Using Join

PHP : ASP : JavaScript : HTML 

Displaying single element of an array

document.write(scripts[2]); // Output is JavaScript

Returning Last element of the Array

The first element starts from 0 hence to show the last element of the array we have subtract one from total number of elements present in the array.

document.write(scripts[scripts.length-1]); // Output is HTML 

Returning First element of the Array

document.write(scripts[0]); // Output is PHP 

Returning all elements with Key

key : 0 =>value: PHP key : 1 =>value: ASP key : 2 =>value: JavaScript key : 3 =>value: HTML

Questions

1. How do you display the elements of a JavaScript array in the console?
2. What is the purpose of using a loop to display array elements?
3. How can you display each array element on a separate line in the console?
4. What method allows you to join the elements of an array into a single string for display?
5. How do you display the length of an array?
6. How can you display array elements on a web page using JavaScript?
7. What is the difference between displaying array elements in the console and on a web page?
8. Can you customize the formatting or style of displayed array elements on a web page?
9. How do you handle empty or undefined array elements when displaying them?
10. How can you dynamically update the displayed array elements in response to changes in the underlying array?

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JavaScript Print Array Elements

1. Different Ways to Print Array Elements in JavaScript
2. Use for Loop to Print Array Elements in JavaScript
3. Use while Loop to Print Array Elements in JavaScript
4. Use forEach Method to Print Array Elements in JavaScript
5. Use console.log() Function to Print Array Elements in JavaScript
6. Use map() With join() Method to Print Array Elements in JavaScript
7. Use toString() Function to Print Array Elements in JavaScript
8. Use join() Function to Print Array Elements in JavaScript
9. Use pop() Function to Print Array Elements in JavaScript
10. Use shift() Method to Print Array Elements in JavaScript
11. Use concat() Method to Print Array Elements in JavaScript
12. Use slice() Method to Print Array Elements in JavaScript

This tutorial demonstrates how you can print JavaScript array elements. It also depends on your project needs, whether you want to print the whole array or a particular number of elements.

Or you want to print array elements in string format or something else. Let’s explore different ways to print JavaScript arrays.

Different Ways to Print Array Elements in JavaScript

The for and while loops iterates over the array elements, one at a time, and each element is printed on a separate line while we can get this same output using the forEach() method.

The forEach() function runs the particular method once for every array element.

We can print all array elements by passing the array’s name to the console.log() function. We can also use map() and join() methods to manipulate first and then print the array’s elements.

For instance, we want to number each array element in the output.

The map() function creates a new array from calling a function once for each element but does not change the original array. Remember, it does not run the function for an empty element.

The join() function acts like a separator that separates the array’s elements with a specified separator.

The pop() returns you the last element while shift() returns the first element of the array, but both are best to use when you want those elements to be removed from a string because both can change the original array.

The toString() function converts the array to string format. The slice() function gives us the selected element of the array as a new array but does not change the original array.

It can also work according to the particular start and end indexes (the end index is exclusive here).

Use for Loop to Print Array Elements in JavaScript

Let’s start with using a simple for loop to print a complete JavaScript array.

var names = ["mehvish", "tahir", "aftab", "martell"]; //for loop  for(var i=0; inames.length; i++)  console.log(names[i]); > 

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