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.

3

27 Answers

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"

Since this answer gained popularity for some reason, 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 value="42abc"></p> <p>What number do you want to extract? <input value="42"></p> <p><button onclick="update()">Insert Coin</button></p> <p></p>
13

You should try the following:

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

result

1234561613213213
4

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,'');
2

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, ''));
1

Using match function.

var thenum = "0a1bbb2".match(/\d+$/)[0]; console.log(thenum);
7

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

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

Tried all the combinations cited above with this Code and got it working, 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 attr but whatever, the solution is better, because its more complete.

1

you may use great parseInt method

it will convert the leading digits to a number

parseInt("-10px"); // will give you -10
2

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 vanilla javascript function:

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

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

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

jsFiddle:

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 wont have it

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 function:

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

You can use regular expression.

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

That will alert 2.

1

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

You can use Underscore String Library as following 

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

result will be : 1

See :

DEMO:

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></div>

JS Code : 

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

if you have suffix as following : 

href="box1az"

You can use the next demo : 

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

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 here:

1

Here's a solt. that checks for no data

var someStr = 'abc'; // add 123 to string to see inverse var thenum = someStr.match(/\d+/); if (thenum != null ) { console.log(thenum[0]); } else { console.log('no number'); }

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

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

please check below javaScripts, there you can get only number 

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

output : 1234567789

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
1

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

Number("strin[g]3".replace(/\D+/g, "")) 
let str = "Total Work Duration: 189.56 Hrs.Present: 23.5 Absent: 2"; let numArr = str.match(/[\d\.]+/g) numArr = numArr.filter(n => n != '.') console.log(numArr)
1

This answer will cover most of the scenario. I can across this situation when user try 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 a array of string as output >> ["34", "56766"]

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

join will convert and concatenate that array data into single string

output >> "3456766"

In my example I need 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')) });

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]);
1
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 function where you need, with parameter.

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

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)

)

written without regex

// 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