PHP从字符串数组中获取数据

To Clarify I used JSON.stringify(myArray) from view before I sent it to controller.

I have string array like following :

[
                [["\"1\"","\"1\""],["\"a\"","\"a\""]],
                [["\"2\"","\"2\""],["\"b\"","\"b\""],["\"c\"","\"c\""]],
                []
]

I want to fetch data by using foreach.

Like :

0- 1, 1 and a,a 
1- 2,2 and b,b and c,c 
2- null

I tried string_data[0][0] , it doesn't work.

And

foreach(string_data[0] as $value){
}

It also doesn't work.

Only string_data[0] works.

Solution is :

json_decode(VARIABLE, true)

Coz it(array) was sent from view as json.Stringfy. Php json decode function make it array again.