php如何将字符串转换为对象或数组[重复]

Current, I am reading a file, which content is in this format:

Array
(
    [0] => Array
        (
            [a] =>
            [b] =>
            [c] => happy
            [d] => mother
            [f] => undergraduate
            [e] => nice
            [g] => hello world
        )
    [1] => Array
        (
            [a] =>
            [b] =>
            [c] => haha
            [d] => father
            [f] => graduate
            [e] => ncoll
            [g] => world
        )
)

Now, I am using file_get_contents function to read the file as a string, and then I don't know how to read the file as an array.

I am trying to get the key and its corresponding value.

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