дерево.txt

  function array2tree($source_arr, $pid, $key_children='children', $key_id='id', $key_pid='parent_id')
    {
        $tree=array();

        if (empty($source_arr))
            return $tree;

        _array2treer($source_arr, $tree, $pid, $pid, $key_children, $key_id, $key_pid);

        return $tree;
    }

    function _array2treer($source_arr, &$_this, $pid, $_this_id, $key_children, $key_id, $key_pid)
    {

        // populate current children
        foreach ($source_arr as $value)
            if ($value[$key_pid]==$_this_id)
                $_this[$key_children][$value[$key_id]]=$value;
//print('$_this[$key_children]='.$value.'<br/>');
        if (isset($_this[$key_children]))
        {
            // populate children of the current children
            foreach ($_this[$key_children] as $value)
                _array2treer($source_arr, $_this[$key_children][$value[$key_id]], $pid, $value[$key_id], $key_children, $key_id, $key_pid);

            // make the tree root look pretty (more convenient to use such tree)
            if ($_this_id===$pid)
                $_this=$_this[$key_children];

        }
    }


    $family = [
        ['id' => 1, 'name' => 'Ñûí Âàñÿ', 'parent_id' => 2],
        ['id' => 3, 'name' => 'Äåäóøêà Èâàí', 'parent_id' => 0],
        ['id' => 2, 'name' => 'Ïàïà Êîëÿ', 'parent_id' => 3],
        ['id' => 4, 'name' => 'Äî÷ü Íèíà', 'parent_id' => 2],
        ['id' => 5, 'name' => 'Âíó÷êà Àíÿ', 'parent_id' => 1],
    ];

    print('<pre>'); print_r($family);print('</pre>');

    $tree=array2tree($family,0);


    ?>

    <p>Ðåçóëüòàò:</p>

    <?php
    print('<pre>'); print_r($tree);print('</pre>');
    ?>