How To Quickly And Easily Loop Through JavaScript Arrays?

You can loop any Array by using different types of looping statements in JavaScript, which I have previously posted. In this post, you can loop through JavaScript Array. At first let you know basic concepts of Array ie. defining array, adding values to the array and accessing array elements.

The Array object is used to store a set of values in a single variable name. You can define an Array object with the new keyword.

The following line of code defines an Array object called myArray.

var myArray=new Array()

You can also define the array size by passing an integer argument as follows.

var myArray=new Array(5)

You can add the values to an array as the following.

var myArray=new Array()
myArray[0]="value1"
myArray[1]="value2"
myArray[2]="value3"

You can also give values to the arrays while defining it as below.

var myArray=new Array("value1", "value2", "value3")

While accessing Arrays, you can refer to a particular element in an array by referring to the name of the array and the index number. The index number starts at 0. The following line accesses the first value of the array myArray.

document.write(myArray[0])

Table of Contents

Loop Through JavaScript Array

You can loop any Array by using any of the following looping statements in JavaScript.

Using For loop

For loop is a basic looping structure. You can loop any Array by using For Loop as below.

var myArray=new Array()
myArray[0]="value1"
myArray[1]="value2"
myArray[2]="value3"
for(i=0; i<myArray.length;i++){
document.write(myArray[i])
}

Example:

<script type="text/javascript">
var mycars=new Array()
mycars[0]="Saab"
mycars[1]="Volvo"
mycars[2]="BMW"
for(i=0; i<mycars.length;i++){
document.write(mycars[i]+"<br/>")
}
</script>

Preview:

Using For… In Statement

There is another looping statement “For…In” statement similar to for loop. You can loop any Array by using “For… In” Statement as below.

var myArray=new Array()
myArray[0]="value1"
myArray[1]="value2"
myArray[2]="value3"
for(x in myArray){
document.write(myArray[x])
}

Example:

<script type="text/javascript">
var mycars=new Array()
mycars[0]="Saab"
mycars[1]="Volvo"
mycars[2]="BMW"
for(x in mycars){
document.write(mycars[x]+"<br/>")
}
</script>

Preview:

Do … while loops

You can also loop any Array by using another looping statement do … while loops as the given below.

var myArray=new Array()
var i=0
myArray[0]="value1"
myArray[1]="value2"
myArray[2]="value3"
do{
document.write(myArray[x])
i++;
}
while(i<myArray.length)

Example:

<script type="text/javascript">
var mycars=new Array()
var i=0
mycars[0]="Saab"
mycars[1]="Volvo"
mycars[2]="BMW"
do{
document.write(mycars[i]+"<br/>")
i++;
}
while(i<mycars.length)
</script>

Preview:

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