Formatting numbers with Javascript

**Traduim** · Sep 19, 2003, 02:58

I have this number:

my_num = 123456789

How could I get this: 123.456.789?

**Mr. Brownstone** · Sep 19, 2003, 06:06

I wrote this code a while back, not knowing whether or not JavaScript had a built-in function for it:

Code:

// ======================================
// Puts some nice comma's into a number
// to make it more readable,
//	eg,	1000 turns into 1,000
//		1000000.32 turns into 1,000,000.32
//		9999999.8888888 turns into 9,999,999.8888888
// and so on. Change sSep into the seperator/delimeter of
// your choice, otherwise "," is the default.
// ======================================

function number_Delimit ( n, sSep ) {

	n = n.toString ( );
	var p1, p2, p3;
	var sSep = ( sSep == null ? ',' : sSep );

	n = n.split ( '.' );
	p1 = n [ 0 ];
	p2 = ( n [ 1 ] == null ? '' : '.' + n [ 1 ] );
	p3 = '';

	for ( var i = p1.length-1 ; i >= 0; i -- ) {
		p3 += p1.charAt ( p1.length - i - 1 );
		if ( i % 3 == 0 && i != 0 ) p3 += sSep;
	}

	return p3 + p2;

}

**xDev** · Sep 19, 2003, 06:35

Seems I got beaten to it, but since I been working on it (for you)
for awhile ...

Code:

<html>
<head>
<title>Format in Threes</title>
<script type="text/javascript">
function formatInThrees(n,d) // n = number, d = delimeter
{
	var myNum = n.toString(),fmat = new Array();
	for(var i = 1; i < myNum.length + 1; i++)
		fmat[i] = myNum.charAt(i-1);

	for(i = 1; i < myNum.length; i++)
	{
		if(i % 3 == 0) {
		fmat[i] += d;
		}
	}
	var val = fmat.join('');
	return val;
}
</script>
</head>
<body bgcolor="#ffffff">
	<form action="">
	Enter a series of numbers:
	<input type="text" name="jin" />
	&nbsp; Result: <input type="text" name="jout" />
	<input type="button" value="Click to Format"
		onclick="this.form.jout.value =
		formatInThrees(this.form.jin.value, '.')" />
	</form>
</body>
</html>

Example calls can be:

formatInThrees(123456789,'.')
// returns 123.456.789

formatInThrees(1234242341234234,',')
// returns 123,424,234,123,423,4

-xDev

**beetle** · Sep 19, 2003, 11:51

My version [img]images/smilies/biggrin.gif[/img]

Code:

String.prototype.group = function( chr, size )
{
	if ( typeof chr == 'undefined' ) chr = ",";
	if ( typeof size == 'undefined' ) size = 3;
	return this.split( '' ).reverse().join( '' ).replace( new RegExp( "(.{" + size + "})(?!$)", "g" ), "$1" + chr ).split( '' ).reverse().join( '' );	
}
 
Number.prototype.group = function( chr, size )
{
	var num = this.toString().split( "." );
	num[0] = num[0].group( chr, size );
	return num.join( "." );
}

var num = 100000000.11111;

alert( num.toString().group() ); // 100,000,000,.11,111

alert( num.group() ); // 100,000,000.11111

alert( num.group( "|", 4 ) ); // 1|0000|0000.11111

**MarcusJT** · Sep 19, 2003, 17:42

Beetle, your first example has a comma next to a decimal point....

100,000,000,.11,111

Surely that's wrong?!

**Mr. Brownstone** · Sep 19, 2003, 18:19

Originally Posted by M@rco

Surely that's wrong?!

I thought so too, but it is not so. Look closer.

**beetle** · Sep 19, 2003, 18:33

That being wrong depends on what you consider right.

If right is returning the string with a comma every 3 characters, then it succeeds.

If right is returning the number with a comma every 3 numbers, but not in the decimal, then it fails.

The method is outputting exactly what it should - the inputted string with comma grouping every three characters. How you interface with it determines success.

Shame on you, M@rco, for doubting me

**Jeff Lange** · Sep 19, 2003, 18:58

I never doubted

**MarcusJT** · Sep 20, 2003, 03:42

Traduim's original post is rather vague, and only appears to call for the digits to be grouped in threes, but given that this thread is in the javascript forum, and the thread is relating to formatting a number, it doesn't take much insight to realise that he wants to format the numbers for presentation to the user.

In case you didn't know, although we in the UK and US (and perhaps other countries) use a comma to delimit the thousands, millions, etc. and a decimal point to indicate where the fractional part of the number starts, in Europe (Traduim is from Catalonia, Spain) they use them the other way round.

Thus, the output of any such formatting must follow the conventions of the way that we write numbers, and thus outputs like "100,000,000,.11,111" (Beetle's) or "123,424,234,123,423,4" (xDev's) are not satisfactory - Beetle's allows a comma and a decimal point to appear together, and xDev's code groups the digits from left to right instead of right to left. Thus the code that each of you present *is* correct in the sense that it answers his original request, but fails to address the underlying need.

I shall leave you both to make the minor modifications to rectify your code!

**xDev** · Sep 20, 2003, 06:01

Originally Posted by M@rco

Traduim's original post is rather vague, and only appears to call for the digits to be grouped in threes, but given that this thread is in the javascript forum, and the thread is relating to formatting a number, it doesn't take much insight to realise that he wants to format the numbers for presentation to the user.

In case you didn't know, although we in the UK and US (and perhaps other countries) use a comma to delimit the thousands, millions, etc. and a decimal point to indicate where the fractional part of the number starts, in Europe (Traduim is from Catalonia, Spain) they use them the other way round.

I shall leave you both to make the minor modifications to rectify your code!

M@rco,

Point well taken! I wasn't sure that he wanted currency formatting, so I just tried to do exactly what he said in the post. However, I can't pass up a chance to give the currency conversion a go:

Code:

<html>
<head>
<title>Format Currency</title>
<script type="text/javascript">
function formatCurrency(n,d) // n = number, d = delimeter
{
	// round to 2 decimals if cents present
   n = (Math.round(n * 100) / 100).toString().split('.');
  var
  	myNum = n[0].toString(),
	fmat = new Array(),
	len = myNum.length,
	i = 1, deci = (d == '.') ? ',' : '.';
  for(i; i < len + 1; i++) fmat[i] = myNum.charAt(i-1);

	fmat = fmat.reverse();
	for(i = 1; i < len; i++)
	{
		if(i % 3 == 0) {
		fmat[i] += d;
		}
	}
	var val = fmat.reverse().join('') +
	 ( n[1] == null ? deci + '00' :
	   (deci + n[1])
	 );
	return val;
}
</script>
</head>
<body style="font: 85% verdana, sans-serif;">
	<form action="">
	Enter a number (float or int):
	<input type="text" name="jin" />
	&nbsp;
	Euros <input type="radio" name="t" checked="checked" />
	Dollars <input type="radio" name="t" /><br />
	Result: <input type="text" name="jout" />
	<input type="button" value="Click to Format"
		onclick="this.form.jout.value =
		formatCurrency(this.form.jin.value,
		(this.form.t[0].checked) ? '.' : ',')" />
	</form>
</body>
</html>

Example calls:

formatCurrency('100000000','.');
// 100.000.000,00

formatCurrency('100000000',',');
// 100,000,000.00

formatCurrency('1000.8756','.');
// 1.000,88

Cheers,
-xDev

**MarcusJT** · Sep 20, 2003, 06:04

That's more like it!

Although... neither I nor he said that it was currency!

**beetle** · Sep 20, 2003, 09:06

M@rco - did you not notice that the Number version of group() properly groups only the non-decimal portion of the number? I did it this way on purpose.

No corrections needed, AFAIK.

For currency

Code:

Number.prototype.round = function( places )
{
	var rounder = Math.pow( 10, places );
	return Math.round( this * rounder ) / rounder;
}
 
Number.prototype.toCurrency = function( unit, point, unitAfter )
{
	if ( typeof unit == "undefined" ) unit = "$";
	if ( typeof point == "undefined" ) point = ".";		
	amt = this.round( 2 ).group( ( point == "." ) ? "," : "." ).replace( ".", point );
	if ( /[.,]\d$/.test( amt ) ) amt += "0";
	return ( unitAfter ) ? amt + " " + unit : unit + " " + amt;
}
 
var sum = 123456.789;
alert( sum.toCurrency() ); // USD
alert( sum.toCurrency( "\u00A3", "," ) ); // English pounds
alert( sum.toCurrency( "F", ",", true ) ); // Francs

**MarcusJT** · Sep 20, 2003, 09:11

Originally Posted by beetle

M@rco - did you not notice that the Number version of group() properly groups only the non-decimal portion of the number? I did it this way on purpose.

No corrections needed, AFAIK.

Ok, I see that works fine for the Number version, my mistake. The example with the string and the ,. threw me off the scent (although I still fail to see how that could ever be of any use to anyone)!!

**beetle** · Sep 20, 2003, 09:15

True enough. But, for my style of coding, I prefer to keep things separate, and with methods like this, attached to the most approriate object. Adding non-numerical characters to a number is a string operation, so I put the bulk of the work there.

**Mr. Brownstone** · Sep 20, 2003, 09:16

It’s very interesting reading all these different ways of performing essentially the same thing, and a learning experience for me too.

Just one thing beetle: Us limeys use the same way to delimit our currency as you yanks; £1,000.99.

**Jeff Lange** · Sep 20, 2003, 09:41

Canada doesn't use commas for number seperation, we use spaces.

(Just in case anyone cares

)

**Mr. Brownstone** · Sep 20, 2003, 10:22

Spaces?

Freaks.

**MarcusJT** · Sep 21, 2003, 04:15

Originally Posted by Jeff Lange

Canada doesn't use commas for number seperation, we use spaces.

(Just in case anyone cares

)

Of course we care! Even though you are freaks!!!

**beetle** · Sep 21, 2003, 09:19

Thanks Mr. Brownstone. What about pence, shillings, crowns, etc, all that crap I hear in period movies -- it's all so confusing. Any of those still used?

**Mr. Brownstone** · Sep 21, 2003, 12:02

The only one of those I know off the top of my head is that a Shilling is (was) worth 12 pence. 20 Shillings was equal to £1 (240 pennies,) but it is now 100 pennies to the pound.

It’s only pounds and pence (pennies) these days, although there are some colloquial variations to the naming of certain amounts. In London, a Monkey is £500, and a Quid is slang for a pound (in and out of London.) There are names for other amounts too, but you’ll need to ask a Cockney for those.

**MarcusJT** · Sep 21, 2003, 12:39

http://www.aldertons.com/money.htm

(although I have never needed to know any of that in my life.. the only slang that I or anyone else I know ever uses is "quid")

**Mr. Brownstone** · Sep 21, 2003, 13:00

Oh, I’ve heard “pony” before:

Stick a pony in me pocket, I’ll fetch the suitcase from the van
Cause if you want the best, and you don’t ask questions
Then brother, I’m your man!

A grand; so frequently used most Brits don’t even think about it. Well, I didn’t.

A tenner and a ton are the only other ones I know and get frequent use.

Interesting link, thanks.

**MarcusJT** · Sep 21, 2003, 13:10

DOH! Grand & tenner... guilty as charged!

Cheers, Del!

**Traduim** · Sep 22, 2003, 06:05

Thank you very much for your help.
It was certainly currency.
Thanks to all.

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