根据对象属性从数组中删除重复项？答案

【问题标题】：Remove duplicates from an array based on object property?根据对象属性从数组中删除重复项？
【发布时间】：2012-05-17 08:36:24
【问题描述】：

我有一个对象数组。我想根据对象中的“名称”值删除重复项。

  [0]=>
  object(stdClass)#337 (9) {
    ["term_id"]=>
    string(2) "23"
    ["name"]=>
    string(12) "Assasination"
    ["slug"]=>
    string(12) "assasination"
  }
  [1]=>
  object(stdClass)#44 (9) {
    ["term_id"]=>
    string(2) "14"
    ["name"]=>
    string(16) "Campaign Finance"
    ["slug"]=>
    string(16) "campaign-finance"
  }
  [2]=>
  object(stdClass)#298 (9) {
    ["term_id"]=>
    string(2) "15"
    ["name"]=>
    string(16) "Campaign Finance"
    ["slug"]=>
    string(49) "campaign-finance-good-government-political-reform"
  }

那么在这种情况下，如何从数组中删除重复的“Campaign Finance”对象。那么整个 [2] 对象呢？

我在这里解决了一堆 PHP 重复数组问题，但似乎没有一个处理对象并仅根据一个参数进行过滤。

【问题讨论】：

标签： php object multidimensional-array duplicate-removal

【解决方案1】：

对于php >=7.0：

由于array_column 自 PHP 7.0 起适用于对象数组，您可以按照@plashenkov 的建议使用以下组合：

$filtered = array_intersect_key($array, array_unique(array_column($array, 'someProperty')));

完整示例：https://3v4l.org/IboLu#v8.0.8

class my_obj
{
        public $term_id;
        public $name;
        public $slug;

        public function __construct($i, $n, $s)
        {
                $this->term_id = $i;
                $this->name = $n;
                $this->slug = $s;
        }
}

$objA = new my_obj(23, 'Assasination', 'assasination');
$objB = new my_obj(14, 'Campaign Finance', 'campaign-finance');
$objC = new my_obj(15, 'Campaign Finance', 'campaign-finance-good-government-political-reform');

$array = array($objA, $objB, $objC);
echo 'Original array:\n';
print_r($array);

/** Answer Code begins here */
$filtered = array_intersect_key($array, array_unique(array_column($array, 'name')));
/** Answer Code ends here */

echo 'After removing duplicates\n';
print_r($filtered);

输出：

Original array:
Array
(
    [0] => my_obj Object
        (
            [term_id] => 23
            [name] => Assasination
            [slug] => assasination
        )

    [1] => my_obj Object
        (
            [term_id] => 14
            [name] => Campaign Finance
            [slug] => campaign-finance
        )

    [2] => my_obj Object
        (
            [term_id] => 15
            [name] => Campaign Finance
            [slug] => campaign-finance-good-government-political-reform
        )

)
After removing duplicates
Array
(
    [0] => my_obj Object
        (
            [term_id] => 23
            [name] => Assasination
            [slug] => assasination
        )

    [1] => my_obj Object
        (
            [term_id] => 14
            [name] => Campaign Finance
            [slug] => campaign-finance
        )

)

term_id 为 15 的对象已被删除，因为它与 term_id 14 同名。

对于php <7.0：

使用现有的键和名称作为值构建一个新数组，使用array_unique（注意它会保留键）。

然后将原始数组中的每个键复制到新数组 ($filtered)（或从原始键中删除所有不在唯一数组中的内容）。

编辑：完整示例：https://3v4l.org/SCrko#v5.6.40

class my_obj
{
        public $term_id;
        public $name;
        public $slug;

        public function __construct($i, $n, $s)
        {
                $this->term_id = $i;
                $this->name = $n;
                $this->slug = $s;
        }
}

$objA = new my_obj(23, 'Assasination', 'assasination');
$objB = new my_obj(14, 'Campaign Finance', 'campaign-finance');
$objC = new my_obj(15, 'Campaign Finance', 'campaign-finance-good-government-political-reform');

$array = array($objA, $objB, $objC);

echo 'Original array:\n';
print_r($array);

/** Answer Code begins here **/

// Build temporary array for array_unique
$tmp = array();
foreach($array as $k => $v)
    $tmp[$k] = $v->name;

// Find duplicates in temporary array
$tmp = array_unique($tmp);

// Build new array with only non-duplicate items
$filtered = [];
foreach($array as $k => $v)
{
    if (array_key_exists($k, $tmp))
        $filtered[$k] = $v;
}

/** Answer Code ends here **/

echo 'After removing duplicates\n';
print_r($filtered);

输出：

Original array:
Array
(
    [0] => my_obj Object
        (
            [term_id] => 23
            [name] => Assasination
            [slug] => assasination
        )

    [1] => my_obj Object
        (
            [term_id] => 14
            [name] => Campaign Finance
            [slug] => campaign-finance
        )

    [2] => my_obj Object
        (
            [term_id] => 15
            [name] => Campaign Finance
            [slug] => campaign-finance-good-government-political-reform
        )

)
After removing duplicates
Array
(
    [0] => my_obj Object
        (
            [term_id] => 23
            [name] => Assasination
            [slug] => assasination
        )

    [1] => my_obj Object
        (
            [term_id] => 14
            [name] => Campaign Finance
            [slug] => campaign-finance
        )

)

term_id 为 15 的对象已被删除，因为它与 term_id 14 同名。

【讨论】：

这很接近，但我也需要访问“slug”和“term_id”键。我正在玩，看看我能不能弄明白。
之后你就有了访问权限，它只是为了找出要删除的键。我将在几秒钟内发布一个完整的示例。
谢谢。在我已经研究了几个小时的一个相当复杂的问题上效果很好。

【解决方案2】：

单线：

$filtered = array_intersect_key($array, array_unique(array_column($array, 'someProperty')));

请注意，array_column() 适用于 PHP 7 及更高版本中的对象数组。

【讨论】：

这应该是经过批准的解决方案。单线永远是最好的！
@UlisesVargasDeSousa 我已将此 PHP >=7.0 解决方案添加到已接受的答案中，同时保留

【解决方案3】：

我一直在寻找一个好的答案，但找不到一个，所以我自己写了一个来处理这种情况，以及你想基于多个属性进行重复数据删除的情况。

$array = DeDupeArrayOfObjectsByProps($array, ['name']);

这是通用函数：

/**
 * Iterates over the array of objects and looks for matching property values.
 * If a match is found the later object is removed from the array, which is returned
 * @param array $objects    The objects to iterate over
 * @param array $props      Array of the properties to dedupe on.
 *   If more than one property is specified then all properties must match for it to be deduped.
 * @return array
 */
public function DeDupeArrayOfObjectsByProps($objects, $props) {
    if (empty($objects) || empty($props))
        return $objects;
    $results = array();
    foreach ($objects as $object) {
        $matched = false;
        foreach ($results as $result) {
            $matchs = 0;
            foreach ($props as $prop) {
                if ($object->$prop == $result->$prop)
                    $matchs++;
            }
            if ($matchs == count($props)) {
                $matched = true;
                break;
            }

        }
        if (!$matched)
            $results[] = $object;
    }
    return $results;
}

这是您的案例的完整用法：

class my_obj {
    public $term_id;
    public $name;
    public $slug;

    public function __construct($i, $n, $s) {
        $this->term_id = $i;
        $this->name = $n;
        $this->slug = $s;
    }
}

$objA = new my_obj(23, "Assasination", "assasination");
$objB = new my_obj(14, "Campaign Finance", "campaign-finance");
$objC = new my_obj(15, "Campaign Finance", "campaign-finance-good-government-political-reform");
$array = array($objA, $objB, $objC);

$array = DeDupeArrayOfObjectsByProps($array, ['name']);
var_dump($array);

【讨论】：

【解决方案4】：

我需要同样的东西...... 这就是我所做的（基于this post，适用于数组和对象）

function my_array_unique_by_subkey($array,$subkey){

    $temp = array();

    $unique = array_filter($array, function ($v) use (&$temp,$subkey) {

        if ( is_object($v) ) $v = (array)$v;

        if ( !array_key_exists($subkey,$v) ) return false;

        if ( in_array($v[$subkey], $temp) ) {
            return false;
        } else {
            array_push($temp, $v[$subkey]);
            return true;
        }
    });

    return $unique;
}

【讨论】：

【解决方案5】：

有点离题，但密切相关：仅按实例对对象数组进行重复数据删除的最短方法：

/**
 * The array must NOT contain scalars.
 *
 * @param mixed[] $objects
 * @return mixed[]
 */
public static function arrayUniqueForObjects(array $objects): array
{
    $deDuplicatedArray = [];

    foreach ($objects as $object) {
        $deDuplicatedArray[spl_object_hash($object)] = $object;
    }

    return array_values($deDuplicatedArray);
}

【讨论】：