获取PHP多维数组的下一个和前一个元素

// 创建一个3维数组
$multiArray = array(
    "level1" => array(
        "level2a" => array(
            "level3a" => "value1",
            "level3b" => "value2"
        ),
        "level2b" => array(
            "level3a" => "value3",
            "level3b" => "value4"
        )
    )
);

// 获取下一个元素
$nextValue = $multiArray["level1"]["level2a"]["level3a"];

// 获取前一个元素
$prevValue = $multiArray["level1"]["level2a"]["level3b"];