数组作为数组PHP

Question

I have an array in php like that:

Array
(
    [0] => Array
        (
            [ref] => a
            [ref_father] => 0
        )

    [1] => Array
        (
            [ref] => b
            [ref_father] => 0
        )
    [2] => Array
        (
            [ref] => c
            [ref_father] => a
        )

How can I create a tree from this array like this :

Array
(
    [0] => Array
        (
            [ref] => a
            [ref_father] => 0
        )

    [1] => Array
        (
            [ref] => c
            [ref_father] => a
        )
    [2] => Array
        (
            [ref] => b
            [ref_father] => 0
        )

that mean I want to display the Father and of below each father his son. Thanks

Answer 1

I would iterate trough the base array and create a new array with the fathers as indexes and all their children in an array.

The new array would look something like:

Array
(
    [0] => Array('a', 'b') // 0 Is the base root
    ['a'] => Array('c')

    ['b'] => Array ()
    ['c'] => Array()

Then, you could use a function like:

$a = array(
    0 => array('a', 'b'),
    'a' => array('c'),
    'b' => array(),
    'c' => array()
);

$depth_array = array();

function build_depth($key, $mapped_array) {
    if (array_key_exists($key, $mapped_array)) {
        if ( count($mapped_array[$key]) == 0 ) return array();
        else {
            foreach( $mapped_array[$key] as $child ) {
                return array($child => build_depth($child, $mapped_array));
            }
        }
    }
}

foreach ( $a[0] as $root_child ) {
    $depth_array[$root_child] = build_depth($root_child, $a); 
}

This will build the depth recursively no matter the depth. Tested here: http://phptester.net/