How to convert a string with regex

Question

How can i convert a string with regex, so that it contains just alphabetical (a-z) or a hyphen. It should get rid " ' ! ? . and so on. Even if they appear multiple times.

// if i have e.g.
var test = '"test!!!"';

// how can i get the value "test"?

Can sombody help. RegEx is totaly new to me.

You can start here http://stackoverflow.com/faq and then when you're done with that you can continue here http://www.regular-expressions.info/ — elclanrs, Oct 14 '12 at 21:35

score 1 · Accepted Answer · answered Oct 14 '12 at 21:34

1

Simply replace the characters you don't want:

'"test!!!"'.replace(/[^a-z-]/gi, '')

[^a-z-] matches all characters but a-z and the hyphen. The /g flag makes the regexp apply multiple times. The /i flag (optional) makes it match case-insensitively, i.e. not replace upper-case characters.

answered Oct 14 '12 at 21:34

phihag

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@Bergi Are you sure? What JavaScript engine are you using? Make sure that you don't forget the `/g` flag. – phihag Oct 14 '12 at 21:38
Yes, but you forgot it at first… – Bergi Oct 14 '12 at 21:39
whould this also replace a hyphen which appears between a-z caracters, like "word-word"? – joh Oct 15 '12 at 09:08
@user1745578 Yes. The expression matches characters, and does not care about order. – phihag Oct 15 '12 at 09:15
so how whould it be if it whould care about order? like matching the hyphen after an end and ignoring it when it appears inbetween? – joh Oct 15 '12 at 09:39
Then you'd use [lookaround assertions](http://www.regular-expressions.info/lookaround.html). However, [lookbehind assertions are not supported in JavaScript](http://stackoverflow.com/questions/9779578/javascript-negative-lookbehind). Therefore, you'd have to join the matches of allowed words instead of filtering out the invalid characters. – phihag Oct 15 '12 at 09:44

score 1 · Answer 2 · answered Oct 14 '12 at 21:34

1

That's quite simple: You build a character class that matches everything except those chars you want and remove them by replacing each occurence (global flag) with the empty string:

return str.replace(/[^a-z-]/g, "");

answered Oct 14 '12 at 21:34

Bergi

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score 0 · Answer 3 · answered Oct 14 '12 at 21:40

0

 str = "hello!! my + name $ is slim-shady";
   console.log(str.replace(/[^a-z-]+/g, ''));

$ node src/java/regex/alphanum.js 
hellomynameisslim-shady

answered Oct 14 '12 at 21:40

Ярослав Рахматуллин

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score 0 · Answer 4 · answered Oct 14 '12 at 21:40

Use the replace method for any string variable and specify the characters you wish to remove.

Here's an example:

 var sampleString = ("Hello World!!");    //Sample of what you have. 
 var holdData = sampleString.replace(/!!/gi, '');
 window.alert(holdData);

score -1 · Answer 5 · answered Oct 14 '12 at 21:35

-1

var str = "test!!!";
str = str.replace(/[^A-Za-z\-]/g,"");

answered Oct 14 '12 at 21:35

Kaustubh Karkare

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How to convert a string with regex

5 Answers5