对数组进行排序,将孩子置于父母之下

Question

所以我在php中有一些项目,有些可能通过parent_id键链接到其他项目.我正在寻找这个数组的排序,以便其父项在此数组中的任何项目最终位于父项目的正下方.

示例:(实际数组有更多键)

some_array[0]['id'] = 15001;
some_array[0]['parent_id'] = 14899;

some_array[1]['id'] = 14723;
some_array[1]['parent_id'] = 0; //parent_id of 0 means item has no parent of its own

some_array[2]['id'] = 14899;
some_array[2]['parent_id'] = 0;

some_array[3]['id'] = 15000;
some_array[3][parent_id'] = 14723;

我想对它们进行排序,以便按顺序排列:

some_array[0]['id'] = 14723;

some_array[1]['id'] = 15000;

some_array[2]['id'] = 14899;

some_array[3]['id'] = 15001;

即.物品就在父母的下方.

提前致谢!

Answer 1

我对马特旺回答的简短版本：

/**
 * sort parents before children
 *
 * @param array   $objects input objects with attributes 'id' and 'parent'
 * @param array   $result  (optional, reference) internal
 * @param integer $parent  (optional) internal
 * @param integer $depth   (optional) internal
 * @return array           output
 */
function parent_sort(array $objects, array &$result=array(), $parent=0, $depth=0) {
    foreach ($objects as $key => $object) {
        if ($object->parent == $parent) {
            $object->depth = $depth;
            array_push($result, $object);
            unset($objects[$key]);
            parent_sort($objects, $result, $object->id, $depth + 1);
        }
    }
    return $result;
}

唯一的实际区别是它对对象数组而不是数组数组进行排序。

Answer 2

我怀疑你们还在寻找一个真正的答案,但它可能会帮助其他人解决同样的问题.下面是一个递归函数,用于使用将子项放在父母下面的数组.

$initial = array(
    array(
        'name' => 'People',
        'ID' => 2,
        'parent' => 0
        ),
    array(
        'name' => 'Paul',
        'ID' => 4,
        'parent' => 2
        ),
    array(
        'name' => 'Liz',
        'ID' => 5,
        'parent' => 2
        ),
    array(
        'name' => 'Comus',
        'ID' => 6,
        'parent' => 3
        ),
    array(
        'name' => 'Mai',
        'ID' => 7,
        'parent' => 2
        ),
    array(
        'name' => 'Titus',
        'ID' => 8,
        'parent' => 3
        ),
    array(
        'name' => 'Adult',
        'ID' => 9,
        'parent' => 6
        ),
    array(
        'name' => 'Puppy',
        'ID' => 10,
        'parent' => 8
        ),
    array(
        'name' => 'Programmers',
        'ID' => 11,
        'parent' => 4
        )   ,
    array(
        'name' => 'Animals',
        'ID' => 3,
        'parent' => 0
        )                           
    );


/*---------------------------------
function parentChildSort_r
$idField        = The item's ID identifier (required)
$parentField    = The item's parent identifier (required)
$els            = The array (required)
$parentID       = The parent ID for which to sort (internal)
$result     = The result set (internal)
$depth          = The depth (internal)
----------------------------------*/

function parentChildSort_r($idField, $parentField, $els, $parentID = 0, &$result = array(), &$depth = 0){
    foreach ($els as $key => $value):
        if ($value[$parentField] == $parentID){
            $value['depth'] = $depth;
            array_push($result, $value);
            unset($els[$key]);
            $oldParent = $parentID; 
            $parentID = $value[$idField];
            $depth++;
            parentChildSort_r($idField,$parentField, $els, $parentID, $result, $depth);
            $parentID = $oldParent;
            $depth--;
        }
    endforeach;
    return $result;
}

$result = parentChildSort_r('ID','parent',$initial);

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

这是一种减速方法,它从原始数组中删除元素,并按正确的顺序将它们放入结果集中.我为你做了一些通用的,所以它只需要你告诉它你的'ID'字段和'parent'字段被调用.顶级项目必须具有0的parent_id(但是您将其命名).