用大括号将字符串拆分为数组

Question

如何将OPTIONS列拆分为数组，其中数组的索引将为字符串中的数字。例如，使用此[OPTIONS] => {0: 'phy','chem','bio'},{1: 'webtech','algo'}将导致Array(    [0] => [        [0] => 'phy',        [1] => 'chem',        [2] => 'bio'    ],    [1] => [        [0] => 'webtech',        [1] => 'algo'    ])Index.php<?php    try {        $pdo = new PDO('mysql:host=localhost;dbname=mydb','root','');        $pdo->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);    } catch (PDOException $e) {        die("Eror");    }    $stmt = $pdo->query("SELECT * FROM table");    $data = $stmt->fetchAll(PDO::FETCH_OBJ);    foreach ($data as $key) {        echo "<pre>";        print_r($key);        echo "</pre>";    }?>结果stdClass Object(    [ID] => 1    [FACULTY_NAME] => APPLIED SCIENCE    [DEPT] => SLT,COMPUTER SCIENCE,FOOD TECHNOLOGY,NUD,HMT,    [OPTIONS] => {0: 'phy','chem','bio'},{1: 'webtech','algo'})