What are the issues with this code? Why is an error reported?-php Tutorial

What is the problem with this code? Why is an error reported? This post was last edited by baidu_27153093 from 2015-05-0611: 31: 40 Array (& nbsp; [0] & nbsp; & gt; & nbsp; Array & nbsp; & what is the problem with this code? Why is an error reported;

This post was last edited by baidu_27153093 at 11:31:40 on

Array
(
    [0] => Array
        (
            [id] => 3
            [fid] => 0
            [name] => 333
            [son] => Array
                (
                    [0] => Array
                        (
                            [id] => 2
                            [fid] => 3
                            [name] => 2_3
                            [son] => Array
                                (
                                    [0] => Array
                                        (
                                            [id] => 4
                                            [fid] => 2
                                            [name] => 2_4
                                        )

                                )

                        )

                    [1] => Array
                        (
                            [id] => 5
                            [fid] => 3
                            [name] => 2_3
                        )

                )

        )

    [1] => Array
        (
            [id] => 1
            [fid] => 0
            [name] => 111
        )

)

This is an array of tree structures. I want to add a hierarchical element to each array element;

Function tree_add_level ($ tree ){
Foreach ($ tree as & $ val ){
If (! Isset ($ val ['_ level']) {
$ Val ['_ level'] = 0; // The top layer is 0.
}
If (isset ($ val ['son']) {
$ Val ['son'] ['_ level'] = $ val [' _ level'] + 1; // add 1 to the lower level
Tree_add_level ($ val ['son']);
}
}
Return $ tree;
}

However, a syntax error is Prompted. find a solution or another method. thank you.
------ Solution ----------------------
Can you paste this array? let me test it.