How can I extract a number from a string in JavaScript?

Question

I have a string in JavaScript (e.g., #box2), and I just want the 2 from it.

I tried:

var thestring = $(this).attr('href'); var thenum = thestring.replace(/(^.+)(\w\d+\w)(.+$)/i, '$2'); alert(thenum);

It still returns #box2 in the alert. How can I get it to work?

It needs to accommodate for any length number attached on the end.

you can simply do like this . it will work well . var thestring = $(this).attr('href'); var thenum = parsefloat(thestring); alert(thenum); — Vivek Shukla
– Vivek Shukla, Commented Jul 3, 2017 at 11:10
this code works fine for me but for one case , I have a string '2.5/mile' and I want to extract 2.5 out of this. Above code gives me 25 instead of 2.5 — Bijay Singh
– Bijay Singh, Commented Aug 27, 2017 at 11:07

5 revs, 2 users 85% · Accepted Answer · 2023-01-23 01:05:50Z

For this specific example,

 var thenum = thestring.replace(/^\D+/g, ''); // Replace all leading non-digits with nothing

In the general case:

 thenum = "foo3bar5".match(/\d+/)[0] // "3"

Here's a bonus: regex generator.

function getre(str, num) { if(str === num) return 'nice try'; var res = [/^\D+/g,/\D+$/g,/^\D+|\D+$/g,/\D+/g,/\D.*/g, /.*\D/g,/^\D+|\D.*$/g,/.*\D(?=\d)|\D+$/g]; for(var i = 0; i < res.length; i++) if(str.replace(res[i], '') === num) return 'num = str.replace(/' + res[i].source + '/g, "")'; return 'no idea'; }; function update() { $ = function(x) { return document.getElementById(x) }; var re = getre($('str').value, $('num').value); $('re').innerHTML = 'Numex speaks: <code>' + re + '</code>'; }

<p>Hi, I'm Numex, the Number Extractor Oracle. <p>What is your string? <input id="str" value="42abc"></p> <p>What number do you want to extract? <input id="num" value="42"></p> <p><button onclick="update()">Insert Coin</button></p> <p id="re"></p>

-1, "#box2_col3".replace( /^\D+/g, '') should have shown 2, not 2_col3.
@shiplu.mokadd.im: I don't see any reference to #box2_col3 in the question.
Yes there is no reference of #box2_col3. But see the regex OP used (\w)(.+$))which clearly indicates there are other characters after the number.
in that case your pattern also fails if there is number before the end.
You could make replace work with leading numbers by using: theString.replace(/^.*\D+/g, '');, but shiplu.mokadd.im's solution is better.

Tomerikoo · Accepted Answer · 2023-06-29 09:09:39Z

337

You should try the following:

var txt = "#div-name-1234-characteristic:561613213213"; var numb = txt.match(/\d/g); numb = numb.join(""); console.log(numb);

edited Jun 29, 2023 at 9:09

Tomerikoo

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answered Jan 4, 2013 at 20:37

Jason Marshall

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4 Comments

Amar Singh Over a year ago

nice answer but what if I want the set of numbers separately. i.e. 1234, 5616133...

Lukas Liesis Over a year ago

Or one-liner + parsing to integer: parseInt(txt.match(/\d/g).join(''), 10)

vsync Over a year ago

" $ 20.0 ".match(/\d/g).join('') => "200" (just saying)

Julfikar Over a year ago

this solution will not extract float. the regex should be /[+-]?\d+(\.\d+)?/g

Peter Mortensen · Accepted Answer · 2023-01-22 22:32:57Z

I think this regular expression will serve your purpose:

var num = txt.replace(/[^0-9]/g, '');

Where txt is your string.

It basically rips off anything that is not a digit.

I think you can achieve the same thing by using this as well:

var num = txt.replace(/\D/g, '');

/[^0-9]/g +1 for readability. Also used with most of the answers here: stackoverflow.com/q/1862130/1066234

xbalaji · Accepted Answer · 2018-02-10 17:21:42Z

Try the following: string.replace(/[^0-9]/g, ''); This will delete all non-digit characters, leaving only digits in the string

function retnum(str) { var num = str.replace(/[^0-9]/g, ''); return parseInt(num,10); }

console.log('abca12bc45qw'.replace(/[^0-9]/g, '')); console.log('#box2'.replace(/[^0-9]/g, ''));

This is better than the accepted answer, since it does replace all non-numbers globally and btw, /[^0-9]/g can be replaced with /[^\d]/g.

Peter Mortensen · Accepted Answer · 2023-01-22 21:46:43Z

60

Using the match function.

var thenum = "0a1bbb2".match(/\d+$/)[0]; console.log(thenum);

edited Jan 22, 2023 at 21:46

Peter Mortensen

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answered Apr 4, 2012 at 1:19

Shiplu Mokaddim

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7 Comments

Sergey Onishchenko Over a year ago

Also you can add unary '+' to make it integer var thenum = +thestring.match(/\d+$/)[0];

Felix Over a year ago

I guess this doesn't work for > 1 digit numbers? (I understand the question was for 1 digit numbers, but I'm looking at numbers possible > 10.)

Shiplu Mokaddim Over a year ago

@nissemand Dont guess. Try yourself. Even you didn't see the fiddle.

Shiplu Mokaddim Over a year ago

@YevgeniyAfanasyev it should not. Check the original question. Specially the last line. Number should be at the end.

Shiplu Mokaddim Over a year ago

@hayley Check the return value of the match function in the MDN.

|

Peter Mortensen · Accepted Answer · 2023-01-23 00:20:01Z

48

And this is a snippet which extracts prices with currency and formatting:

var price = "£1,739.12"; parseFloat(price.replace(/[^\d\.]*/g, '')); // 1739.12

edited Jan 23, 2023 at 0:20

Peter Mortensen

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answered Dec 16, 2015 at 11:56

LachoTomov

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1 Comment

NoobCoder Over a year ago

What if I want 1,739.12 ?

Peter Mortensen · Accepted Answer · 2023-01-22 23:32:53Z

I tried all the combinations cited in the previous answer with this code and got it working. It was the only one that worked on that string → (12) 3456-7890

var str = "(12) 3456-7890"; str.replace(/\D+/g, '');

Result: "1234567890"

Obs: I know that a string like that will not be on the attribute, but whatever, the solution is better, because it’s more complete.

i think better will be str.match(/\d+/g).map(Number) it will return an array

Peter Mortensen · Accepted Answer · 2023-01-22 23:35:11Z

19

You may use the great parseInt() method.

It will convert the leading digits to a number:

parseInt("-10px"); // Will give you -10

edited Jan 22, 2023 at 23:35

Peter Mortensen

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answered May 14, 2014 at 9:05

Eugene Tiurin

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2 Comments

Russj Over a year ago

this only works when the number is at the beginning of the string

Ahmed Syed Over a year ago

its returning NaN

Peter Mortensen · Accepted Answer · 2023-01-23 01:12:13Z

You can extract numbers from a string using a regex expression:

let string = "xxfdx25y93.34xxd73"; let res = string.replace(/\D/g, ""); console.log(res);

Output: 25933473

Wrap it into a vanilla JavaScript function:

function onlyNumbers(text){ return text.replace(/\D/g, ""); }

Peter Mortensen · Accepted Answer · 2023-01-23 01:15:24Z

function justNumbers(string) { var numsStr = string.replace(/[^0-9]/g, ''); return parseInt(numsStr); } console.log(justNumbers('abcdefg12hijklmnop'));

You can do a function like this

function justNumbers(string) { var numsStr = string.replace(/[^0-9]/g, ''); return parseInt(numsStr); }

Remember: if the number has a zero in front of it, the int won’t have it

Wiktor Stribiżew · Accepted Answer · 2020-02-21 11:04:34Z

12

For a string such as #box2, this should work:

var thenum = thestring.replace(/^.*?(\d+).*/,'$1');

jsFiddle:

http://jsfiddle.net/dmeku/

edited Feb 21, 2020 at 11:04

Wiktor Stribiżew

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answered Apr 4, 2012 at 1:19

icyrock.com

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Comments

Peter Mortensen · Accepted Answer · 2023-01-23 01:30:30Z

To return an int from the string, you can do the following code. It removes all not number characters and returns an integer.

Number("strin[g]3".replace(/\D+/g, ""))

Peter Mortensen · Accepted Answer · 2023-01-23 01:25:21Z

If you want to parse a number from a price like $6,694.20, it can be done this way:

parseFloat('$6,694.20'.replace(/^\D|,+/g, ''))

Or via a function:

function parsePrice(value) { return parseFloat(value.replace(/^\D|,+/g, '')) } parsePrice('$6,694.20') // 6694.2

Note that in case there may be more than one character at the beginning of the string which is not part of the number, you'll want to use value.replace(/^\D+|,+/g, '')

Peter Mortensen · Accepted Answer · 2023-01-23 01:39:11Z

let str = "Total Work Duration: 189.56 Hrs.Present: 23.5 Absent: 2"; /* The provided regex globally matches the character "." and a digit from the string */ let numArr = str.match(/[\d\.]+/g) /* It returns an array [189.56, ., 23.5, 2], and uses the filter function to remove the '.' */ numArr = numArr.filter(n => n != '.') console.log(numArr)

While this code snippet may solve the question, including an explanation really helps to improve the quality of your post. Remember that you are answering the question for readers in the future, and those people might not know the reasons for your code suggestion.

Peter Mortensen · Accepted Answer · 2023-01-22 21:47:56Z

6

You can use a regular expression.

var txt="some text 2"; var numb = txt.match(/\d/g); alert (numb);

That will alert 2.

edited Jan 22, 2023 at 21:47

Peter Mortensen

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answered Apr 4, 2012 at 1:20

Robby Shaw

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1 Comment

Shiplu Mokaddim Over a year ago

-1 multiple digits will not be captured and for using array in alert

BaronBaleron · Accepted Answer · 2020-10-21 00:50:34Z

If someone need to preserve dots in extracted numbers:

var some = '65,87 EUR'; var number = some.replace(",",".").replace(/[^0-9&.]/g,''); console.log(number); // returns 65.87

Peter Mortensen · Accepted Answer · 2023-01-22 22:30:14Z

You can use Underscore.js' string library as follows:

var common = "#box" var href = "#box1" _(href).strRight(common)

The result will be: 1

See: Underscore.string

Demo:

http://jsfiddle.net/abdennour/Vyqtt/

HTML code:

<p> <a href="#box1" >img1</a> <a href="#box2" >img2</a> <a href="#box3" >img3</a> <a href="#box4" >img4</a> </p> <div style="font-size:30px"></div>

JavaScript code:

var comm = "#box" $('a').click(function() { $('div').html(_($(this).attr('href')).strRight(comm))})

If you have a suffix as follows:

href="box1az"

You can use the following demo:

http://jsfiddle.net/abdennour/Vyqtt/1/

function retrieveNumber(all, prefix, suffix) { var left = _(all).strRight(prefix); return _(left).strLeft(suffix); }

Peter Mortensen · Accepted Answer · 2023-01-23 00:10:07Z

Here's a solution that checks for no data:

var someStr = 'abc'; // Add 123 to string to see the inverse var thenum = someStr.match(/\d+/); if (thenum != null) { console.log(thenum[0]); } else { console.log('Not a number'); }

Peter Mortensen · Accepted Answer · 2023-01-23 00:37:25Z

Please check the below JavaScript code. There you can get only a number.

var txt = "abc1234char5678#!9"; var str = txt.match(/\d+/g, "") + ''; var s = str.split(',').join(''); alert(Number(s));

Output: 1234567789

Peter Mortensen · Accepted Answer · 2023-01-23 00:46:52Z

3

var elValue = "-12,erer3 4,-990.234sdsd"; var isNegetive = false; if(elValue.indexOf("-") == 0) isNegetive = true; elValue = elValue.replace( /[^\d\.]*/g, ''); elValue = isNaN(Number(elValue)) ? 0 : Number(elValue); if(isNegetive) elValue = 0 - elValue; alert(elValue); // -1234990.234

edited Jan 23, 2023 at 0:46

Peter Mortensen

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answered Jun 16, 2019 at 9:30

Manoj Chavanke

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2 Comments

mentallurg Over a year ago

Ad an explanation. E.g. why you use namely this regex.

Peter Mortensen Over a year ago

Where was this copied from? The misspelling "negetive" might be a good signature.

Ruslan · Accepted Answer · 2015-10-08 12:32:15Z

Use this one-line code to get the first number in a string without getting errors:

var myInt = parseInt(myString.replace(/^[^0-9]+/, ''), 10);

Peter Mortensen · Accepted Answer · 2023-01-23 01:40:14Z

2

Written without a regular expression:

// Without Regex function extractNumber(string) { let numArray = string.split('').map(item => { if (typeof +item === 'number' && !isNaN(+item)) return +item }) return +numArray.join('') } extractNumber('@1200milion$') // 1200

edited Jan 23, 2023 at 1:40

Peter Mortensen

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answered Nov 15, 2021 at 19:10

ehsan parsania

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2 Comments

Peter Mortensen Over a year ago

What are all the leading pluses (+) for?

ehsan parsania Over a year ago

@PeterMortensen " + " is a shorthand to convert a string to number +item === Number(item)

chineseducks · Accepted Answer · 2020-07-08 02:07:28Z

You need to add "(/\d+/g)" which will remove all non-number text, but it will still be a string at this point. If you create a variable and "parseInt" through the match, you can set the new variables to the array values. Here is an example of how I got it to work:

 var color = $( this ).css( "background-color" ); var r = parseInt(color.match(/\d+/g)[0]); var g = parseInt(color.match(/\d+/g)[1]); var b = parseInt(color.match(/\d+/g)[2]);

Hello! This question already has an accepted answer. Before looking at answered questions, please consider looking at unanswered ones first. If you do, however, have something to add to an answered question, please consider reading other answers thoroughly first.
Re ""(/\d+/g)" which will remove all non-number text": Really? It presumably comes with a qualification. That needs to be explained in the answer. (But ***** without ***** "Edit:", "Update:", or similar - the answer should appear as if it was written today)

Peter Mortensen · Accepted Answer · 2023-01-23 01:06:46Z

This answer will cover most of the scenarios. I came across this situation when a user tried to copy paste the phone number.

$('#help_number').keyup(function() { $(this).val().match(/\d+/g).join("") });

Explanation:

str = "34%^gd 5-67 6-6ds" str.match(/\d+/g)

It will give an array of strings as output:

["34", "56766"]

str.match(/\d+/g).join("")

join() will convert and concatenate that array data into a single string.

Output:

"3456766"

In my example, I needed the output as 209-356-6788, so I used replace():

$('#help_number').keyup(function() { $(this).val($(this).val().match(/\d+/g).join("").replace(/(\d{3})\-?(\d{3})\-?(\d{4})/, '$1-$2-$3')) });

Peter Mortensen · Accepted Answer · 2023-01-23 01:28:39Z

In one of my projects I had to take a rating value from a string. This is what I used:

let text = '#xbox2' let num = text.trim(). split(''). map(num => Number(num)). filter(x => Number.isInteger(x))

Peter Mortensen · Accepted Answer · 2023-01-23 01:49:36Z

With regular expressions, how to get numbers from a string, for example:

String myString = "my 2 first gifts were made by my 4 brothers"; myString = myString.replaceAll("\\D+", ""); System.out.println("myString: " + myString);

The result of myString is "24".

You can see an example of this running code at http://ideone.com/iOCf5G.

java !== javascript - replaceAll does not exist in standard javascript. Only some libraries like jQuery have that method. In the future, you should clarify.

X 47 48 - IR · Accepted Answer · 2024-08-20 21:52:07Z

There are multiple ways.

// Using match, match all the digits '#box2'.match(/\d+/g).join('') // Using replace, remove everything other than digits '#box2'.replace(/[^\d]+/g, '') // Using slice '#box2'.slice(4)

Peter Mortensen · Accepted Answer · 2023-01-23 01:03:18Z

Use:

changeStrangeDate(dateString: string) { var sum = 0; var numbers = dateString.match(/\d+/g); if (numbers.length > 1) { numbers.forEach(element => { sum += parseInt(element); } ); } console.log(new Date(sum).toDateString()); return new Date(sum).toUTCString(); }

You can do it like that and then call a function where you need it, with a parameter.

this.changeStrangeDate('/Date(1551401820000-0100)/');

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