Help with thousands separator regexp

[serendipity]

I want to add thousands separator to a number.

The number: 100000000000.00
Should look like: 100,000,000,000.00

I tried the below:

Code: Select all

$num= 100000000000.00;
$num= regexreplace ($num, "(-?[0-9]+)([0-9]{3})","$1,$2"); 

but that gives me 100000000,000.00

Any help?

PS: Meanwhile I am using the code 4 times in a row to achieve what i want.

[jacky]

This should do it:

Code: Select all

$num = regexreplace($num, "(\d{1,3})(?=(\d{3})+(?!\d))", "$1,");

[serendipity]

This should do it:

Code: Select all

$num = regexreplace($num, "(\d{1,3})(?=(\d{3})+(?!\d))", "$1,");

, you're the best! Thanks.
Shame, i don't have time to learn RegExp.