用PHP解析JSON数据..大型数据集

下面是我试图解析并放入数据库的数据集。。。我正在使用此代码

$json = json_decode($string);
$json[0]['segments']['layover'] gives access error...

sizeof（$json）也不返回任何内容。。。

$json不返回null，已检查，使用echo-var_dump（$json）打印

我试着通过这个。。。不起作用。。尝试了一个数组类型，并表示我非法访问stdIN对象。。。有没有像DOMDocument（）这样简单的东西可以遍历json？

---json

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也是如此