Extract a number from a string using JavaScript

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The number from a string in javascript can be extracted into an array of numbers by using the match method. This function takes a regular expression as an argument and extracts the number from the string. Regular expression for extracting a number is (/(\d+)/).

Example 1: This example uses match() function to extract numbers from strings.

html

<div align="center" style="background-color: green;">

<h1>GeeksforGeeks</h1>

<h3>Extract number from string</h3>

<p>String is "jhkj7682834"</p>

<p id="GFG">

Click the button to extract number

</p>

<input type="button" value="click " onclick="myGeeks()">

</div>

<script>

function myGeeks() {

var str = "jhkj7682834";

var matches = str.match(/(\d+)/);

if (matches) {

document.getElementById('GFG').innerHTML

= matches[0];

}

</script>

Output:

Extract a number from a string

Example 2: This example uses the match() function to extract numbers from strings.

html

<body>

<div align="center" style="background-color: green;">

<h1>GeeksforGeeks</h1>

<h3>Extract number from string</h3>

<p>String is "foo35bar5jhkj88"</p>

<h3>

The string contains 3 numbers. So the numbers

are stored in an array and print together

</h3>

<p id="GFG">

Click the button to extract number

</p><br>

<h3 id="Geeks"></h3>

<input type="button" value="Click Here!" onclick="myGeeks()">

</div>

<script>

function myGeeks() {

var str = "foo35bar5jhkj88";

matches = str.match(/\d+/g);

var i=0

document.getElementById('GFG').innerHTML

= matches[0] + matches[1] + matches[2];

document.getElementById("Geeks").innerHTML

= "Where 35 is the first, 5 is the second"

+ " and 88 is the third number"

}

</script>

</body>

Output:

Extract a number from a string

Example 3: This example uses reduce method to extract all the numbers from the string.

HTML

<body>

<div align="center" style="background-color: green;">

<h1>GeeksforGeeks</h1>

<h3>

</h3>

<p>String is "jhkj7682834"</p>

<p id="GFG">

Click the button to extract number

</p>

<input type="button" value="click " onclick="myGeeks()">

</div>

<script>

function myGeeks() {

var str = "jhkj7682834";

var c = '0123456789'

function check(x) {

return c.includes(x) ? true : false;

}

var matches = [...str].reduce((x, y) => check(y) ? x+y : x, '')

if (matches) {

document.getElementById('GFG').innerHTML

= matches;

}

</script>

</body>

Output:

Extract a number from a string

JavaScript is best known for web page development but it is also used in a variety of non-browser environments. You
can learn JavaScript from the ground up by following this JavaScript Tutorial and JavaScript Examples.