CODEWITHSUNDEEP
javascriptregexspecial-characters
Timothy Ruhle
Timothy Ruhle

Reputation: 7597

Remove all special characters with RegExp

I would like a RegExp that will remove all special characters from a string. I am trying something like this but it doesn’t work in IE7, though it works in Firefox.

var specialChars = "!@#$^&%*()+=-[]\/{}|:<>?,.";

for (var i = 0; i < specialChars.length; i++) {
  stringToReplace = stringToReplace.replace(new RegExp("\\" + specialChars[i], "gi"), "");
}

A detailed description of the RegExp would be helpful as well.

Upvotes: 315

Views: 706352

Answers (11)

Kiritushka
Kiritushka

Reputation: 1130

Removing all characters except letters and numbers:

str.replace(/[^\p{L}\d]+/gu, '')

If you need to leave spaces:

str.replace(/[^\p{L}\d\s]+/gu, '')

Upvotes: 2

tyne
tyne

Reputation: 115

text.replace(/[`~!@#$%^*()_|+\-=?;:'",.<>\{\}\[\]\\\/]/gi, '');

Upvotes: 0

Fuad All
Fuad All

Reputation: 975

@Seagull anwser (https://stackoverflow.com/a/26482552/4556619) looks good but you get undefined string in result when there are some special (turkish) characters. See example below.

let str="bənövşəyi 😟пурпурный İdÖĞ";

i slightly improve it and patch with undefined check.

function removeSpecials(str) {
    let lower = str.toLowerCase();
    let upper = str.toUpperCase();

    let res = "",i=0,n=lower.length,t;
    for(i; i<n; ++i) {
        if(lower[i] !== upper[i] || lower[i].trim() === ''){
            t=str[i];
            if(t!==undefined){
                res +=t;
            }
        }
    }
    return res;
}

Upvotes: 0

Manikanta C.S.E
Manikanta C.S.E

Reputation: 417

using \W or [a-z0-9] regex won't work for non english languages like chinese etc.,

It's better to use all special characters in regex and exclude them from given string

str.replace(/[~`!@#$%^&*()+={}\[\];:\'\"<>.,\/\\\?-_]/g, '');

Upvotes: 15

Seagull
Seagull

Reputation: 3600

The first solution does not work for any UTF-8 alphabet. (It will cut text such as Їжак). I have managed to create a function which does not use RegExp and use good UTF-8 support in the JavaScript engine. The idea is simple if a symbol is equal in uppercase and lowercase it is a special character. The only exception is made for whitespace. 

function removeSpecials(str) {
    var lower = str.toLowerCase();
    var upper = str.toUpperCase();

    var res = "";
    for(var i=0; i<lower.length; ++i) {
        if(lower[i] != upper[i] || lower[i].trim() === '')
            res += str[i];
    }
    return res;
}

Update: Please note, that this solution works only for languages where there are small and capital letters. In languages like Chinese, this won't work.

Update 2: I came to the original solution when I was working on a fuzzy search. If you also trying to remove special characters to implement search functionality, there is a better approach. Use any transliteration library which will produce you string only from Latin characters and then the simple Regexp will do all magic of removing special characters. (This will work for Chinese also and you also will receive side benefits by making Tromsø == Tromso).

Upvotes: 11

freedev
freedev

Reputation: 30027

Plain Javascript regex does not handle Unicode letters.

Do not use [^\w\s], this will remove letters with accents (like àèéìòù), not to mention to Cyrillic or Chinese, letters coming from such languages will be completed removed.

You really don't want remove these letters together with all the special characters. You have two chances:

  • Add in your regex all the special characters you don't want remove,
    for example: [^èéòàùì\w\s].
  • Have a look at xregexp.com. XRegExp adds base support for Unicode matching via the \p{...} syntax.

var str = "Їжак::: résd,$%& adùf"
var search = XRegExp('([^?<first>\\pL ]+)');
var res = XRegExp.replace(str, search, '',"all");

console.log(res); // returns "Їжак::: resd,adf"
console.log(str.replace(/[^\w\s]/gi, '') ); // returns " rsd adf"
console.log(str.replace(/[^\wèéòàùì\s]/gi, '') ); // returns " résd adùf"
<script src="https://cdnjs.cloudflare.com/ajax/libs/xregexp/3.1.1/xregexp-all.js"></script>

Upvotes: 31

Eldar Mammadov
Eldar Mammadov

Reputation: 49

str.replace(/\s|[0-9_]|\W|[#$%^&*()]/g, "") I did sth like this. But there is some people who did it much easier like str.replace(/\W_/g,"");

Upvotes: 2

noinput
noinput

Reputation: 1877

Note that if you still want to exclude a set, including things like slashes and special characters you can do the following:

var outString = sourceString.replace(/[`~!@#$%^&*()_|+\-=?;:'",.<>\{\}\[\]\\\/]/gi, '');

take special note that in order to also include the "minus" character, you need to escape it with a backslash like the latter group. if you don't it will also select 0-9 which is probably undesired.

Upvotes: 170

millebii
millebii

Reputation: 1287

I use RegexBuddy for debbuging my regexes it has almost all languages very usefull. Than copy/paste for the targeted language. Terrific tool and not very expensive.

So I copy/pasted your regex and your issue is that [,] are special characters in regex, so you need to escape them. So the regex should be : /!@#$^&%*()+=-[\x5B\x5D]\/{}|:<>?,./im

Upvotes: 2

annakata
annakata

Reputation: 75794

var desired = stringToReplace.replace(/[^\w\s]/gi, '')

As was mentioned in the comments it's easier to do this as a whitelist - replace the characters which aren't in your safelist.

The caret (^) character is the negation of the set [...], gi say global and case-insensitive (the latter is a bit redundant but I wanted to mention it) and the safelist in this example is digits, word characters, underscores (\w) and whitespace (\s).

Upvotes: 761

AnD
AnD

Reputation: 3129

why dont you do something like:

re = /^[a-z0-9 ]$/i;
var isValid = re.test(yourInput);

to check if your input contain any special char

Upvotes: -1

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