对象的array_unique？

Question

是否有像array_unique这样的对象方法？我有一堆带有'Role'对象的数组,我合并了,然后我想取出重复项:)

Answer 1

array_unique使用SORT_REGULAR以下对象来处理对象数组:

class MyClass {
    public $prop;
}

$foo = new MyClass();
$foo->prop = 'test1';

$bar = $foo;

$bam = new MyClass();
$bam->prop = 'test2';

$test = array($foo, $bar, $bam);

print_r(array_unique($test, SORT_REGULAR));

将打印:

Array (
    [0] => MyClass Object
        (
            [prop] => test1
        )

    [2] => MyClass Object
        (
            [prop] => test2
        )
)

请在此处查看:http://3v4l.org/VvonH#v529

警告:它将使用"=="比较,而不是严格比较("===").

因此,如果要删除对象数组中的重复项,请注意它将比较每个对象属性,而不是比较对象标识(实例).

Answer 2

好吧,array_unique()比较元素的字符串值:

注意:当且仅(string) $elem1 === (string) $elem2当字符串表示相同时,才使用两个元素相等,将使用第一个元素.

因此,请确保__toString()在您的类中实现该方法,并为相等的角色输出相同的值,例如

class Role {
    private $name;

    //.....

    public function __toString() {
        return $this->name;
    }

}

如果它们具有相同的名称,则会将两个角色视为相等.

Answer 3

我知道已经有了一个公认的答案,但这里有另一种选择.

与之前的答案相反,它使用,in_array()因为PHP 5 中比较对象的性质允许我们这样做.利用此对象比较行为要求数组只包含对象,但这似乎就是这种情况.

$merged = array_merge($arr, $arr2);
$final  = array();

foreach ($merged as $current) {
    if ( ! in_array($current, $final)) {
        $final[] = $current;
    }
}

var_dump($final);

Answer 4

这是一种删除数组中重复对象的方法:

<?php
// Here is the array that you want to clean of duplicate elements.
$array = getLotsOfObjects();

// Create a temporary array that will not contain any duplicate elements
$new = array();

// Loop through all elements. serialize() is a string that will contain all properties
// of the object and thus two objects with the same contents will have the same
// serialized string. When a new element is added to the $new array that has the same
// serialized value as the current one, then the old value will be overridden.
foreach($array as $value) {
    $new[serialize($value)] = $value;
}

// Now $array contains all objects just once with their serialized version as string.
// We don't care about the serialized version and just extract the values.
$array = array_values($new);

Answer 5

您还可以先序列化:

$unique = array_map( 'unserialize', array_unique( array_map( 'serialize', $array ) ) );

从PHP 5.2.9开始,您可以使用可选sort_flag SORT_REGULAR:

$unique = array_unique( $array, SORT_REGULAR );

Answer 6

如果要根据特定属性过滤对象,也可以使用它们的array_filter函数:

//filter duplicate objects
$collection = array_filter($collection, function($obj)
{
    static $idList = array();
    if(in_array($obj->getId(),$idList)) {
        return false;
    }
    $idList []= $obj->getId();
    return true;
});

Answer 7

从这里:http://php.net/manual/en/function.array-unique.php#75307

这个也适用于对象和数组.

<?php
function my_array_unique($array, $keep_key_assoc = false)
{
    $duplicate_keys = array();
    $tmp         = array();       

    foreach ($array as $key=>$val)
    {
        // convert objects to arrays, in_array() does not support objects
        if (is_object($val))
            $val = (array)$val;

        if (!in_array($val, $tmp))
            $tmp[] = $val;
        else
            $duplicate_keys[] = $key;
    }

    foreach ($duplicate_keys as $key)
        unset($array[$key]);

    return $keep_key_assoc ? $array : array_values($array);
}
?>