字符串的分割问题

Question

看如下代码：$num="123456789426";
            $i=0;
            for(;$i<strlen($num);){
                $q=substr($num, $i, 3);
                if(strlen($q)<3){
                    echo $q;
                }else if(substr($num, -1)==substr($q, -1)){
                    echo $q.",";
                }else{
                    echo $q.",";
                }
                $i=$i+3;
            }我的最终目的是想让这个字符串每3位一组，但最后的结果是123,456,789,426,  。怎样改才能显示为123,456,789,426这样的结果呢？
请大侠帮忙！

Answer 1

$num="123456789426";
echo implode(',',str_split($num,3));

Answer 2

echo number_format($num,0);  即可

Answer 3

$num="1234567894";
echo strrev(implode(',',str_split(strrev($num),3)));

Answer 4

或者直接用数字的处理方法
$num="1234567894";
echo number_format($num);