Quick way to extract alphanumeric characters from a string in Javascript

Question

I know that I can write a simple loop to check each character in a string and see if it is a alphanumeric character. If it is one, concat it to a new string. And thats it.

But, is there a more elegant shortcut to do so. I have a string (with CSS selectors to be precise) and I need to extract only alphanumeric characters from that string.

Sometimes you cannot be both short and elegant while being quick at the same time. — Spencer Wieczorek, Jul 21 '16 at 19:03
View this entry from 2008: "[RegEx for JavaScript to allow only alphanumeric](http://stackoverflow.com/questions/388996/regex-for-javascript-to-allow-only-alphanumeric)". — JohnH, Jul 21 '16 at 19:06

score 16 · Accepted Answer · edited Jul 21 '16 at 19:06

16

Many ways to do it, basic regular expression with replace

var str = "123^&*^&*^asdasdsad";
var clean = str.replace(/[^0-9A-Z]+/gi,"");
console.log(str);
console.log(clean);

edited Jul 21 '16 at 19:06

Patrick Roberts

49,224
10
102
153

answered Jul 21 '16 at 19:04

epascarello

204,599
20
195
236

`\d` is probably better than `0-9` – Patrick Roberts Jul 21 '16 at 19:04
The "i" is what i missed in my attempts! – Sunny Jul 22 '16 at 03:57

score 1 · Answer 2 · answered Jul 21 '16 at 19:13

"sdfasfasdf1 yx6fg4 { df6gjn0 } yx".match(/([0-9a-zA-Z ])/g).join("")

where sdfasfasdf1 yx6fg4 { df6gjn0 } yx can be replaced by string variable. For example

var input = "hello { font-size: 14px }";
console.log(input.match(/([0-9a-zA-Z ])/g).join(""))

You can also create a custom method on string for that. Include into your project on start this

String.prototype.alphanumeric = function () {
    return this.match(/([0-9a-zA-Z ])/g).join("");
}

then you can everythink in your project call just

var input = "hello { font-size: 14px }";
console.log(input.alphanumeric());

or directly

"sdfasfasdf1 yx6fg4 { df6gjn0 } yx".alphanumeric()

score -1 · Answer 3 · answered Jul 21 '16 at 19:08

-1

var NewString = (OldString).replace(/([^0-9a-z])/ig, "");

where OldString is the string you want to remove the non-alphanumeric characters from

answered Jul 21 '16 at 19:08

user3163495

2,425
2
26
43

Quick way to extract alphanumeric characters from a string in Javascript

3 Answers3