I have an array i.e.

Array
(
    [18] => 0.6667
    [228] => 0.3333
    [25] => 0.3333
    [568] => 0.3333
    [762] => 0
    [740] => 0
    [742] => 0
)

I want to rank them as

Array
(
    [18] => 0.6667  //1
    [228] => 0.3333 //2
    [25] => 0.3333  //2
    [568] => 0.3333  //2
    [762] => 0       //3
    [740] => 0       //3
    [742] => 0       //3
)

I have tried using following code:

arsort($rank);
foreach ($rank as $k => $v) {
        $i=1;
        foreach ($rank as $k1 => $v1) {
            if($v==$v1){
                $newrank[$k]=$i;
            }
            else{
                $i++;
            }
        }
    }

But it gives me result

Array
(
    [18] => 0.6667  //1
    [228] => 0.3333 //2
    [25] => 0.3333  //2
    [568] => 0.3333  //2
    [762] => 0       //5
    [740] => 0       //5
    [742] => 0       //5
)

I am unable to rectify why rank is increasing from 2 to 5.

Please help.

You don't need nested loops. Just iterate through the array, and increment $i whenever the score changes.

$newrank = array();
$i = 0;
$last_v = null;
foreach ($rank as $k => $v) {
    if ($v != $last_v) {
        $i++;
        $last_v = $v;
    }
    $newrank[$k] = $i;
}