通过链接导航多个对象而无需重复 [英] Navigating multiple objects by links without repetition
问题描述
我正在尝试浏览一堆带有其他对象链接的对象.我想以1的ID开头并浏览每个对象.有些对象将循环回到先前的对象，因此我想确保只对每个对象进行一次查看，否则我将陷入无限循环.我还希望能够通过浏览链接来判断无法访问哪些对象.我认为导航顺序无关紧要.
I am trying to navigate through a bunch of objects with links to other objects. I want to start with id of 1 and navigate through each of the objects. Some of the objects will loop back to previous objects, so I want to make sure I look at each one only once otherwise I will get stuck in an infinite loop. I also want to be able to tell which objects cannot be accessed by navigating through the links. I don't think the order of navigation matters.
这是我可能会遇到的示例数据集(我的实际数据将来自数据库):
Here is a sample dataset I might encounter (my actual data will be coming from a database):
<?php
$obj_array = [] ;
$obj = new stdClass;
$obj->id = 1;
$obj->name = "Apple";
$obj->link = array(14, 5);
$obj_array[] = $obj;
$obj = new stdClass;
$obj->id = 3;
$obj->name = "Carrot";
$obj->link = array(1, 14, 3);
$obj_array[] = $obj;
$obj = new stdClass;
$obj->id = 4;
$obj->name = "Dill";
$obj->link = array(1, 5);
$obj_array[] = $obj;
$obj = new stdClass;
$obj->id = 5;
$obj->name = "Egg";
$obj->link = array(6);
$obj_array[] = $obj;
$obj = new stdClass;
$obj->id = 6;
$obj->name = "Fred";
$obj->link = array(7);
$obj_array[] = $obj;
$obj = new stdClass;
$obj->id = 7;
$obj->name = "Goat";
$obj->link = array(7, 8);
$obj_array[] = $obj;
$obj = new stdClass;
$obj->id = 8;
$obj->name = "Harry";
$obj_array[] = $obj;
$obj = new stdClass;
$obj->id = 9;
$obj->name = "Igloo";
$obj->link = array(14, 5);
$obj_array[] = $obj;
$obj = new stdClass;
$obj->id = 10;
$obj->name = "Jason";
$obj->link = array(1, 5, 8);
$obj_array[] = $obj;
$obj = new stdClass;
$obj->id = 11;
$obj->name = "Klaus";
$obj->link = array(1, 5, 10);
$obj_array[] = $obj;
$obj = new stdClass;
$obj->id = 14;
$obj->name = "Banana";
$obj->link = array(3);
$obj_array[] = $obj;
$obj = new stdClass;
$obj->id = 15;
$obj->name = "Oyster1";
$obj->link = array(16);
$obj_array[] = $obj;
$obj = new stdClass;
$obj->id = 16;
$obj->name = "Oyster2";
$obj->link = array(15);
$obj_array[] = $obj;
我希望看到类似这样的内容(顺序无关紧要):
I would expect to see something like this (order doesn't matter):
已处理:
Apple
Banana
Carrot
Egg
Fred
Goat
Harry
未链接:
Dill
Igloo
Jason
Klaus
Oyster1
Oyster2
我如何创建一个循环来遍历这样的结构，尤其是当每个对象可以具有多个链接时?
How can I create a loop to loop through a structure like this especially when each object can have multiple links?
推荐答案
尽管 @wizards答案有效，但我还是觉得想用一个更清晰的代码制作一个版本.在低于版本的版本中，将返回带有链接和未插入元素的对象，我相信它的工作原理非常清楚.
Although @wizards answer worked, I felt I wanted to make a version with a bit clearer code. Below version returns an object with the linked and unlined elements, and I believe it's very clear how it works.
我想要这样工作的原因是，可以将其扩展为将来的问题.例如链接多少次"或链接最多".也可以很容易地将其改编为回答这些问题.
The reason I want to work like this, is to be able to extend it for future questions. Like "How many times is an item linked" or "Which has the most links". It can be easily adapted to answer these questions also.
另一个好处是，它使用了尽可能有限的循环，当大小增加时，可以使速度大大提高.
Another benefit is that it uses as limited loops as possible, which could speed things up quite a bit when the size increases.
<?php
error_reporting(E_ALL);
$obj_array = [] ;
$obj = new stdClass;
$obj->id = 1;
$obj->name = "Apple";
$obj->link = array(14, 5);
$obj_array[] = $obj;
$obj = new stdClass;
$obj->id = 3;
$obj->name = "Carrot";
$obj->link = array(1, 14, 3);
$obj_array[] = $obj;
$obj = new stdClass;
$obj->id = 4;
$obj->name = "Dill";
$obj->link = array(1, 5);
$obj_array[] = $obj;
$obj = new stdClass;
$obj->id = 5;
$obj->name = "Egg";
$obj->link = array(6);
$obj_array[] = $obj;
$obj = new stdClass;
$obj->id = 6;
$obj->name = "Fred";
$obj->link = array(7);
$obj_array[] = $obj;
$obj = new stdClass;
$obj->id = 7;
$obj->name = "Goat";
$obj->link = array(7, 8);
$obj_array[] = $obj;
$obj = new stdClass;
$obj->id = 8;
$obj->name = "Harry";
$obj_array[] = $obj;
$obj = new stdClass;
$obj->id = 9;
$obj->name = "Igloo";
$obj->link = array(14, 5);
$obj_array[] = $obj;
$obj = new stdClass;
$obj->id = 10;
$obj->name = "Jason";
$obj->link = array(1, 5, 8);
$obj_array[] = $obj;
$obj = new stdClass;
$obj->id = 11;
$obj->name = "Klaus";
$obj->link = array(1, 5, 10);
$obj_array[] = $obj;
$obj = new stdClass;
$obj->id = 14;
$obj->name = "Banana";
$obj->link = array(3);
$obj_array[] = $obj;
$obj = new stdClass;
$obj->id = 15;
$obj->name = "Oyster1";
$obj->link = array(16);
$obj_array[] = $obj;
$obj = new stdClass;
$obj->id = 16;
$obj->name = "Oyster2";
$obj->link = array(15);
$obj_array[] = $obj;
/*
* CALL
*/
$parser = new ObjectLinker($obj_array, 1);
//dump found
//decode/encode to only show public values
print_r(json_decode(json_encode($parser)));
/*
* ACTUAL CODE
*/
class ObjectLinker
{
private $_array;
private $_start;
public $LinkedElements = array();
public $UnLinkedElements = array();
final public function __construct($ar, $start)
{
$this->_array = $ar;
$this->_start = $start;
$this->getElementsArray();
$this->findLinked($this->_start);
}
final private function getElementsArray()
{
//since each Id is unique, i'm using the ID as the key in the array. this will allow faster access
//Ofcourse it would be better if you would create the array like this in the first place, then you can skip this step
foreach($this->_array as $obj) {
if (!is_null($obj) && property_exists($obj, 'id')) {
//I add everything to the unlinked elements. We will remove the linked once, to have once less loop
$this->UnLinkedElements[$obj->id] = $obj;
}
}
}
final private function findLinked($id)
{
//If the key is not in the array, it's already loaded
if (!array_key_exists($id, $this->UnLinkedElements)) {
return;
}
//get obj
//Because of the getElementsArray() step, I'm already sure the object exists.
//If you change the input array, you might want to check for invalid obj
$obj = $this->UnLinkedElements[$id];
//add to linked
$this->LinkedElements[$id] = $obj;
//remove from unlinked
unset($this->UnLinkedElements[$id]);
//no links
if (!property_exists($obj, 'link')) {
return;
}
$links = $obj->link;
//Invalid links
if (!is_array($links)) {
return;
}
//check links
foreach($links as $link) {
$this->findLinked($link);
}
}
}
?>
输出:
stdClass Object
(
[LinkedElements] => stdClass Object
(
[1] => stdClass Object
(
[id] => 1
[name] => Apple
[link] => Array
(
[0] => 14
[1] => 5
)
)
[14] => stdClass Object
(
[id] => 14
[name] => Banana
[link] => Array
(
[0] => 3
)
)
[3] => stdClass Object
(
[id] => 3
[name] => Carrot
[link] => Array
(
[0] => 1
[1] => 14
[2] => 3
)
)
[5] => stdClass Object
(
[id] => 5
[name] => Egg
[link] => Array
(
[0] => 6
)
)
[6] => stdClass Object
(
[id] => 6
[name] => Fred
[link] => Array
(
[0] => 7
)
)
[7] => stdClass Object
(
[id] => 7
[name] => Goat
[link] => Array
(
[0] => 7
[1] => 8
)
)
[8] => stdClass Object
(
[id] => 8
[name] => Harry
)
)
[UnLinkedElements] => stdClass Object
(
[4] => stdClass Object
(
[id] => 4
[name] => Dill
[link] => Array
(
[0] => 1
[1] => 5
)
)
[9] => stdClass Object
(
[id] => 9
[name] => Igloo
[link] => Array
(
[0] => 14
[1] => 5
)
)
[10] => stdClass Object
(
[id] => 10
[name] => Jason
[link] => Array
(
[0] => 1
[1] => 5
[2] => 8
)
)
[11] => stdClass Object
(
[id] => 11
[name] => Klaus
[link] => Array
(
[0] => 1
[1] => 5
[2] => 10
)
)
[15] => stdClass Object
(
[id] => 15
[name] => Oyster1
[link] => Array
(
[0] => 16
)
)
[16] => stdClass Object
(
[id] => 16
[name] => Oyster2
[link] => Array
(
[0] => 15
)
)
)
)
这篇关于通过链接导航多个对象而无需重复的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
