Programming for beginners: JavaScript: Array

Array is an ordered collection of elements.

Syntax

var arrayName = [elem1, elem2 .... elemN];

var arrayName = new Array(size)

How to access element of an array?

By using index notation, you can access element of an array. Index starts from 0.

Syntax

arrayName[index]

arr[0] : Return the first element

arr[1] : Return 2^nd element

…..

arr[n] : Return n-1th element

array.html

<!DOCTYPE html>

<html>

<head>
    <title>Array</title>
</head>

<body>
    <script type="text/javascript">
        var arr = [2, "Hello", 123.5, true];

        document.write("arr[0] : " + arr[0] + "<br />");
        document.write("arr[1] : " + arr[1] + "<br />");
        document.write("arr[2] : " + arr[2] + "<br />");
        document.write("arr[3] : " + arr[3] + "<br />");
        document.write("arr[4] : " + arr[4] + "<br />");
        document.write(typeof arr);
    </script>
</body>

</html>

Open above page in browser, you can able to see following data.

arr[0] : 2

arr[1] : Hello

arr[2] : 123.5

arr[3] : true

arr[4] : undefined

object

What is the maximum index number in array?

Arrays in javaScript use 32-bit indexes. So the maximum array index number is ((2^32)-2) = 4294967294 (Since arrays are zero indexed).

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Programming for beginners

Saturday 1 September 2018

JavaScript: Array

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