PHP String Formatter

<?php

function format($format, $value, $separator=' ')
{
    $temp=[];
    foreach ($format as $cluster){
        $formattedCluster=substr($value,0,strlen($cluster));
        $value=substr($value,strlen($cluster));
        array_push($temp, $formattedCluster);
    }
    return join($separator, $temp);
}

var_dump(format(['xx', 'xxx', 'xxx','xxx','xx'], '6282222222222'));