StringsInPHP - //Problem 5. Custom Sorting

//Problem 5.    Custom Sorting
//Write function that sort array according to the element with that index in the string. For example if given index is 2, sort array by //second index of string.
<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title></title>
    </head>
    <body>
        <form method="post" action="CustomString.php">
            <input type="text" name="str1">
            <input type="submit" value="GO">
        </form>
    </body>
</html>
<?php
$int=1;//sorting index
$myArr=array("ovca","kashta","agne","abreviatura","buldog", "123456789");
foreach($myArr as $v){
    $newArr[$v]=substr($v, $int);
}
asort($newArr);
foreach($newArr as $k=>$vv){
    $finalArr[]=$k;
}
echo '<pre>' . print_r($finalArr, true) . '</pre>';
?>