'x' * 5 is 'xxxxx' in Python – How do I do that in CoffeeScript/JavaScript?

Question

I want to create a string by concatenating multiple copies of another in CoffeeScript or JavaScript.

Do I have to create my own function for this or is there a shortcut like in Python?

Justin Niessner · Accepted Answer · 2012-10-17T21:10:00.453

4

You could use this shortcut (need to pass the number of repetitions plus 1):

Array(6).join 'x'

edited Oct 17 '12 at 21:10

answered Oct 17 '12 at 21:06

Justin Niessner

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This is similar to the accepted answer to [a very similar question](http://stackoverflow.com/questions/202605/repeat-string-javascript). – Oct 17 '12 at 21:07
@JustinNiessner: I edited for a reason. It won't work in this form in plain Javascript. – jAndy Oct 17 '12 at 21:08
1

That only gets you four x's. Fence post problem. – Chris Oct 17 '12 at 21:08
@jAndy - It will work properly in CoffeeScript (it's not JavaScript). – Justin Niessner Oct 17 '12 at 21:09
Not sure about coffe script, but in javascript (chromes console) I got; `new Array(5).join('x') == 'xxxx'` (4 'x' only) – Renato Gama Oct 17 '12 at 21:09
@JustinNiessner: You should at least add the line as valid js-function call since the OP also asked for javascript. – jAndy Oct 17 '12 at 21:09
@jAndy - The OP asked for a CoffeeScript solution. I provided one. – Justin Niessner Oct 17 '12 at 21:11
@JustinNiessner: well, if you ignore the parenthesis, you're right. – jAndy Oct 17 '12 at 21:12
@JustinNiessner: naarh, ok I should have been more explicit on that comment. What I meant was, the parenthesis in the OP's question title. Nvm :p – jAndy Oct 17 '12 at 21:16

score 3 · Answer 2 · answered Oct 17 '12 at 21:13

This is coming in the next version of ECMAScript, so you might as well implement it as a shim.

http://wiki.ecmascript.org/doku.php?id=harmony:string.prototype.repeat

From the proposal:

Object.defineProperty(String.prototype, 'repeat', {
    value: function (count) {
        var string = '' + this;
        //count = ToInteger(count);
        var result = '';
        while (--count >= 0) {
            result += string;
        }
        return result;
    },
    configurable: true,
    enumerable: false,
    writable: true
});

Then call .repeat() from a string:

"x".repeat(5); // "xxxxx"

score 0 · Answer 3 · answered Oct 17 '12 at 21:10

0

You can use array.join(JavaScript). Array()

function extend(ch, times){

    return Array(times+1).join('x');
}
 extend('x', 5);

answered Oct 17 '12 at 21:10

Anoop

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'x' * 5 is 'xxxxx' in Python – How do I do that in CoffeeScript/JavaScript?

3 Answers3