Format a number using given format

numbergrouping.php

<?php
function formatNumber($format, $string)
{
	$numMatches = preg_match_all("/(#+)/", $format, $matches);     
	preg_match("/\d+/", $string, $numberpart);   
	preg_match("/\.\d*/", $string, $decimalpart);   
	$groupedNumber = (count($decimalpart)>0)?$decimalpart[0]:"";
	$start = $end = strlen($numberpart[0]);  
	if($numMatches==0){
	    return $string;
	}
	while($start>0)
	{
	    $match = $matches[0]{$numMatches-1};
	    $matchLen = strlen($match);
	    $start = $end - $matchLen;
	    $groupedNumber = substr($string ,$start, $end-$start).$groupedNumber ;
	    $end -=  $matchLen;
	    if($numMatches > 1){
		//use the last pattern for the rest of the number
		$numMatches--;
	    }
	    if($start>0){
		$groupedNumber = ",".$groupedNumber;
	    }
	}  
	return $groupedNumber;
}

print formatNumber("##,##,###", "123456789")."\n";
print formatNumber("##,##,##", "123456789123456789")."\n";
print formatNumber("##,####", "123456789123456789")."\n";
print formatNumber("##,####", "123456789123456.789")."\n";

?>