Regex to replace multiple spaces with a single space

Question

Given a string like:

"The dog      has a long   tail, and it     is RED!"

What kind of jQuery or JavaScript magic can be used to keep spaces to only one space max?

Goal:

"The dog has a long tail, and it is RED!"

Answer 1

Given that you also want to cover tabs, newlines, etc, just replace \s\s+ with ' ':

string = string.replace(/\s\s+/g, ' ');

If you really want to cover only spaces (and thus not tabs, newlines, etc), do so:

string = string.replace(/  +/g, ' ');

Answer 2

Since you seem to be interested in performance, I profiled these with firebug. Here are the results I got:

str.replace( /  +/g, ' ' )       ->  380ms
str.replace( /\s\s+/g, ' ' )     ->  390ms
str.replace( / {2,}/g, ' ' )     ->  470ms
str.replace( / +/g, ' ' )        ->  790ms
str.replace( / +(?= )/g, ' ')    -> 3250ms

This is on Firefox, running 100k string replacements.

I encourage you to do your own profiling tests with firebug, if you think performance is an issue. Humans are notoriously bad at predicting where the bottlenecks in their programs lie.

(Also, note that IE 8's developer toolbar also has a profiler built in -- it might be worth checking what the performance is like in IE.)

Answer 3

var str = "The      dog        has a long tail,      and it is RED!";
str = str.replace(/ {2,}/g,' ');

EDIT: If you wish to replace all kind of whitespace characters the most efficient way would be like that:

str = str.replace(/\s{2,}/g,' ');

Answer 4

A more robust method: This takes care of also removing the initial and trailing spaces, if they exist. Eg:

// NOTE the possible initial and trailing spaces
var str = "  The dog      has a long   tail, and it     is RED!  "

str = str.replace(/^\s+|\s+$|\s+(?=\s)/g, "");

// str -> "The dog has a long tail, and it is RED !"

Your example didn't have those spaces but they are a very common scenario too, and the accepted answer was only trimming those into single spaces, like: " The ... RED! ", which is not what you will typically need.

Answer 5

This is one solution, though it will target all space characters:

"The      dog        has a long tail,      and it is RED!".replace(/\s\s+/g, ' ')

"The dog has a long tail, and it is RED!"

Edit: This is probably better since it targets a space followed by 1 or more spaces:

"The      dog        has a long tail,      and it is RED!".replace(/  +/g, ' ')

"The dog has a long tail, and it is RED!"

Alternative method:

"The      dog        has a long tail,      and it is RED!".replace(/ {2,}/g, ' ')
"The dog has a long tail, and it is RED!"

I didn't use /\s+/ by itself since that replaces spaces that span 1 character multiple times and might be less efficient since it targets more than necessary.

I didn't deeply test any of these so lmk if there are bugs.

Also, if you're going to do string replacement remember to re-assign the variable/property to its own replacement, eg:

var string = 'foo'
string = string.replace('foo', '')

Using jQuery.prototype.text:

var el = $('span:eq(0)');
el.text( el.text().replace(/\d+/, '') )

Answer 6

I have this method, I call it the Derp method for lack of a better name.

while (str.indexOf("  ") !== -1) {
    str = str.replace(/  /g, " ");
}

Running it in JSPerf gives some surprising results where it beat some of the more sophisticated approaches EDIT Original JSPerf link http://jsperf.com/removing-multiple-spaces/3 seems to be dead at the time

Answer 7

Here is an alternate solution if you do not want to use replace (replace spaces in a string without using replace javascript)

var str="The dog      has a long   tail, and it     is RED!";
var rule=/\s{1,}/g;

str = str.split(rule).join(" "); 

document.write(str);

Answer 8

More robust:

function trim(word)
{
    word = word.replace(/[^\x21-\x7E]+/g, ' '); // change non-printing chars to spaces
    return word.replace(/^\s+|\s+$/g, '');      // remove leading/trailing spaces
}

Answer 9

I suggest

string = string.replace(/ +/g," ");

for just spaces
OR

string = string.replace(/(\s)+/g,"$1");

for turning multiple returns into a single return also.

Answer 10

Also a possibility:

str.replace( /\s+/g, ' ' )

Answer 11

I know that I am late to the party, but I discovered a nice solution.

Here it is:

var myStr = myStr.replace(/[ ][ ]*/g, ' ');

Answer 12

Comprehensive unencrypted answer for newbies et al.

This is for all of the dummies like me who test the scripts written by some of you guys which do not work.

The following 3 examples are the steps I took to remove special characters AND extra spaces on the following 3 websites (all of which work perfectly) {1. EtaVisa.com 2. EtaStatus.com 3. Tikun.com} so I know that these work perfectly.

We have chained these together with over 50 at a time and NO problems.

// This removed special characters + 0-9 and allows for just letters (upper and LOWER case)

function NoDoublesPls1()
{
var str=document.getElementById("NoDoubles1");
var regex=/[^a-z]/gi;
str.value=str.value.replace(regex ,"");
}

// This removed special characters and allows for just letters (upper and LOWER case) and 0-9 AND spaces

function NoDoublesPls2()
{
var str=document.getElementById("NoDoubles2");
var regex=/[^a-z 0-9]/gi;
str.value=str.value.replace(regex ,"");
}

// This removed special characters and allows for just letters (upper and LOWER case) and 0-9 AND spaces // The .replace(/\s\s+/g, " ") at the end removes excessive spaces // when I used single quotes, it did not work.

function NoDoublesPls3()
{    var str=document.getElementById("NoDoubles3");
var regex=/[^a-z 0-9]/gi;
str.value=str.value.replace(regex ,"") .replace(/\s\s+/g, " ");
}

::NEXT:: Save #3 as a .js // I called mine NoDoubles.js

::NEXT:: Include your JS into your page

 <script language="JavaScript" src="js/NoDoubles.js"></script>

Include this in your form field:: such as

<INPUT type="text" name="Name"
     onKeyUp="NoDoublesPls3()" onKeyDown="NoDoublesPls3()" id="NoDoubles3"/>

So that it looks like this

<INPUT type="text" name="Name" onKeyUp="NoDoublesPls3()" onKeyDown="NoDoublesPls3()" id="NoDoubles3"/>

This will remove special characters, allow for single spaces and remove extra spaces.

Answer 13

var string = "The dog      has a long   tail, and it     is RED!";
var replaced = string.replace(/ +/g, " ");

Or if you also want to replace tabs:

var replaced = string.replace(/\s+/g, " ");

Answer 14

It's as easy as doing:

const myString = "  Hello     World       !   "
const parsed = myString.replace(/ +/g, ' ') // " Hello World ! "

Now, if you wanna get rid of the starting and ending spaces, you can do:

const trimmed = parsed.trim() // "Hello World !"

ONE LINER (TL;DR)

const parsedSTring = "   John     Doe    ".replace(/ +/g, ' ').trim() // "John Doe"

Answer 15

// replace multiple white spaces with one white space

String replacedDisplayName = displayName.replaceAll("\\s{2,}", " ");

Answer 16

var myregexp = new RegExp(/ {2,}/g);

str = str.replace(myregexp,' ');

Answer 17

var text = `xxx  df dfvdfv  df    
                     dfv`.split(/[\s,\t,\r,\n]+/).filter(x=>x).join(' ');

result:

"xxx df dfvdfv df dfv"

Answer 18

I know we have to use regex, but during an interview, I was asked to do WITHOUT USING REGEX.

@slightlytyler helped me in coming with the below approach.

const testStr = "I   LOVE    STACKOVERFLOW   LOL";

const removeSpaces = str  => {
  const chars = str.split('');
  const nextChars = chars.reduce(
    (acc, c) => {
      if (c === ' ') {
        const lastChar = acc[acc.length - 1];
        if (lastChar === ' ') {
          return acc;
        }
      }
      return [...acc, c];
    },
    [],
  );
  const nextStr = nextChars.join('');
  return nextStr
};

console.log(removeSpaces(testStr));

Answer 19

here is my solutions that work well for me:

var text = "    Tes ddas    dMd WAlkman 3Dsfd    "
    .toLowerCase()
    .replace(/\b\s+/g, " ")
    .replace(/\b\w/g, s => s.toUpperCase())
    .trimStart()
    .trimEnd();
    
console.log(text);

// result: Tes Ddas Dmd Walkman 3dsfd

Answer 20

We can use the following regex explained with the help of sed system command. The similar regex can be used in other languages and platforms.

Add the text into some file say test

manjeet-laptop:Desktop manjeet$ cat test
"The dog      has a long   tail, and it     is RED!"

We can use the following regex to replace all white spaces with single space

manjeet-laptop:Desktop manjeet$ sed 's/ \{1,\}/ /g' test
"The dog has a long tail, and it is RED!"

Hope this serves the purpose

Answer 21

Try this to replace multiple spaces with a single space.

<script type="text/javascript">
    var myStr = "The dog      has a long   tail, and it     is RED!";
    alert(myStr);  // Output 'The dog      has a long   tail, and it     is RED!'

    var newStr = myStr.replace(/  +/g, ' ');
    alert(newStr);  // Output 'The dog has a long tail, and it is RED!'
</script>

Read more @ Replacing Multiple Spaces with Single Space

Answer 22

For more control you can use the replace callback to handle the value.

value = "tags:HUNT  tags:HUNT         tags:HUNT  tags:HUNT"
value.replace(new RegExp(`(?:\\s+)(?:tags)`, 'g'), $1 => ` ${$1.trim()}`)
//"tags:HUNT tags:HUNT tags:HUNT tags:HUNT"

Answer 23

This script removes any white space (multiple spaces, tabs, returns, etc) between words and trims:

// Trims & replaces any wihtespacing to single space between words
String.prototype.clearExtraSpace = function(){
  var _trimLeft  = /^\s+/,
      _trimRight = /\s+$/,
      _multiple  = /\s+/g;

  return this.replace(_trimLeft, '').replace(_trimRight, '').replace(_multiple, ' ');
};

Answer 24

' mouse pointer touch '.replace(/^\s+|\s+$|(\s)+/g, "$1") should do the trick!

Answer 25

Using nodepad++ function, below regex works fine for me,

Find: {1}\K\s+
Replace:leave it empty

Answer 26

let nameCorrection = function (str) {
  let strPerfect = str.replace(/\s+/g, " ").trim();
  let strSmall = strPerfect.toLowerCase();
  let arrSmall = strSmall.split(" ");
  let arrCapital = [];
  for (let x of arrSmall.values()) {
    arrCapital.push(x[0].toUpperCase() + x.slice(1));
  }

  let result = arrCapital.join(" ");
  console.log(result);
};
nameCorrection("Pradeep kumar dHital");

Answer 27

def removeblanks(text): return re.sub(r'\s\s+'," ",text) I was working on a large textual data with a lot of duplicate spaces. The above RE worked for me. All the duplicate blank spaces were replaced by a single space.