ইউনিকোড সংখ্যার পরিবর্তন

<?php
function convert($char){

    switch($char){
        case "1":
            return "&#2535;";
            break;
        case "2":
            return "&#2536;";
            break;
        case "3":
            return "&#2537;";
            break;
        case "4":
            return "&#2538;";
            break;
        case "5":
            return "&#2539;";
            break;
        case "6":
            return "&#2540;";
            break;
        case "7":
            return "&#2541;";
            break;
        case "8":
            return "&#2542;";
            break;
        case "9":
            return "&#2543;";
            break;
        case "0":
            return "&#2534;";
            break;
        default:
            return $char;
            break;
    
    }
}
function unicode($str){
$count=strlen($str);
$uni='';
    for($i=0;$i<$count;$i++){
        if(is_int($i)){
            $uni.=convert(substr($str,$i,1));
        }
    }
    $uni=str_replace('Today','&#2438;&#2460;&#2453;&#2503;',$uni);
    $uni=str_replace('Yesterday','&#2455;&#2468;&#2453;&#2494;&#2482;',$uni);
return $uni;
}

//echo unicode('Today 23:33:43');

?>