Php Round - aprox到小数

I have the next code for average.

    function array_average2(){
    $args = func_get_args();
    if(isset($args[0])){
        if(is_array($args[0])){
            $ret = (array_sum($args[0]) / count($args[0]));
        }else{
            $ret = (array_sum($args) / func_num_args());
        }
    }else{
        $ret = 0;
    }

$ret2=0.01 * (int)($ret*100);
return $ret2;
}

i need php round to rezult next:
$ret=1.23 - i need 1
$ret=6.23 - i need 6
$ret=6.70 - i need 7
$ret=5.50 - i need 5.50
$ret=5.49 - i need 5

Conclusion if decimal is next to 0.50 to be next value, else previous but if it is fix 0.50 to stai. 5+6=5.50.. don't change

Well make use of the round() in PHP and apply this logic

function array_average2(){
    $args = func_get_args();
    if(isset($args[0])){
        if(is_array($args[0])){
            $ret = (array_sum($args[0]) / count($args[0]));
        }else{
            $ret = (array_sum($args) / func_num_args());
        }
    }else{
        $ret = 0;
    }

    $ret2=0.01 * (int)($ret*100);
    $str = strval($ret);
    if(strpos($str,'.50')!==false)
    {
        return $ret;
    }
    else
    {
        return round($ret2);
    }
}

Probably not the best but it should work:

$string = (string)$ret;

if (substr($string, -3) != '.50') {
    $ret = round($ret);
}

OR

$string = (string)$ret;

if (strrpos($string, '.50') !== 0) {
    $ret = round($ret);
}