How to make 8 digit number in javascript?

Question

I am trying to make an auto-generator of numbers. but I'm having a problem on how to forced the number to 8 digit.


for(i=1;i<=100;i++) {
  var i = x++;

  var test = i.toFixed(8); // I used this but this is only for decimals

  jQuery('.generated_table').append(test+'<br />');;
}

Please help.

Do you mean you'd like them zero-padded so that they're always shown as 8 characters? e.g. 23 should be written as 00000023? — Simon Whitaker, Feb 12 '11 at 13:31
Also, you set the iterator variable inside the loop. Are you sure that you want to do that? — Šime Vidas, Feb 12 '11 at 13:32

KooiInc · Answer 1 · 2011-02-12T14:22:23.017

Use toPrecision:

(10000000).toPrecision(8); //=> '10000000'
(100).toPrecision(8); //=> '100.00000'

If you meant preceding a number with leading zero's:

var i = (100).toPrecision(8).split('.').reverse().join(''); //=> '00000100'

You can also make a Number.prototype function of that:

Number.prototype.leadingZeros = function(n) {
    return this.toPrecision(n).split('.').reverse().join('');
};

(100).leadinZeros(8); //=> '00000100'

Just to be complete: a more precise way to print any (number of) leading character(s) to any number may be:

Number.prototype.toWidth = function(n,chr) {
    chr = chr || ' ';
    var len = String(parseFloat(this)).length;
    function multiply(str,nn){
        var s = str;
        while (--nn>0){
            str+=s;
        }
        return str;
    }
    n = n<len ? 0 : Math.abs(len-n);
    return (n>1 && n ? multiply(chr,n) : n<1 ? '' : chr)+this;
};
(100).toWidth(8,'0'); //=> 00000100

Very creative :) But, it doesn't work for integers with more than 8 digits, or decimal fractions. — Šime Vidas, Feb 12 '11 at 13:41

score 1 · Accepted Answer · answered Feb 12 '11 at 13:51

1

Whooo!!! i got anser :: Try it

for(i=1;i<=100;i++) {
  //var i = x++;

  var test = i.toPrecision(8).replace("\.","");     
  jQuery('.generated_table').append(test+'<br />');;
}

answered Feb 12 '11 at 13:51

Manish Trivedi

3,481
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You are appending the zeros, but I think they should be prepended. – Šime Vidas Feb 12 '11 at 14:01
@Sim:: Ohhk!! He is not mentioned that appending or prepended. Any-way Thanks for this. :) – Manish Trivedi Feb 12 '11 at 14:11

score 0 · Answer 3 · edited May 23 '17 at 10:24

0

Check out this SO question for some links to various printf-style functions for Javascript: Javascript printf/string.format

edited May 23 '17 at 10:24

Community

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answered Feb 12 '11 at 13:36

Simon Whitaker

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score 0 · Answer 4 · answered Feb 12 '11 at 13:41

0

var randNum = "";
var MAX_LENGTH = 8;

while(randNum.toString().length < MAX_LENGTH){
 var temp = Math.floor(Math.random() * 10);
 randNum += temp.toString();
}

alert(randNum);

answered Feb 12 '11 at 13:41

daniel

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How to make 8 digit number in javascript?

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