先看数据

Array
(
    [id] => 82
    [by] => folder_id
    [names] => 跑跑车辆
    [type] => attrs
    [offset] => 0
    [page_id] => 1
    [page_size] => 15
    [article_table] => attrs
    [ext] => [
'key'  => 'dir',
'data' => [
'app' => ['id'=>'82,154', 'names' => 'app,跑跑卡丁车', 'article_table' => 'tags'],
'xinwen'  => ['id'=>'159', 'names' => '跑跑卡丁车', 'article_table' => 'tags'],
'pingce'  => ['id'=>'82', 'names' => '跑跑卡丁车车辆', 'article_table' => 'attrs'],
'cheshou' => ['id'=>'82', 'names' => '跑跑卡丁车人物', 'article_table' => 'attrs'],
'ditu'    => ['id'=>'82', 'names' => '跑跑卡丁车赛道', 'article_table' => 'attrs'],
'tupian'  => ['id'=>'82', 'names' => '跑跑卡丁车游戏图片', 'article_table' => 'attrs']
]]
)

实现思路：把数组先转化为json字符串，然后把字符串转化为数组
代码：
$extJson = str_replace(['=>', "'", '[', ']'], [':', '"', '{', '}'], $ext);
$extArr = json_decode($extJson, true);

如何检测json格式是否正确，请参考我另一篇文章：https://blog.csdn.net/liuxl57805678/article/details/102912796