php 对象的array_unique？
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array_unique for objects?
提问by Johannes
Is there any method like the array_unique for objects? I have a bunch of arrays with 'Role' objects that I merge, and then I want to take out the duplicates :)
有没有像 array_unique 这样的对象方法？我有一堆带有我合并的“角色”对象的数组，然后我想取出重复项:)
回答by Matthieu Napoli
array_uniqueworks with an array of objects using SORT_REGULAR:
array_unique使用以下方法处理一组对象SORT_REGULAR：
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));
Will print:
将打印：
Array (
[0] => MyClass Object
(
[prop] => test1
)
[2] => MyClass Object
(
[prop] => test2
)
)
See it in action here: http://3v4l.org/VvonH#v529
在这里查看它的实际效果：http: //3v4l.org/VvonH#v529
Warning: it will use the "==" comparison, not the strict comparison ("===").
警告：它将使用“==”比较，而不是严格比较（“===”）。
So if you want to remove duplicates inside an array of objects, beware that it will compare each object properties, not compare object identity (instance).
因此，如果您想删除对象数组中的重复项，请注意它会比较每个对象的属性，而不是比较对象身份（实例）。
回答by Felix Kling
Well, array_unique()compares the string value of the elements:
好吧，array_unique()比较一下元素的字符串值：
Note: Two elements are considered equal if and only if
(string) $elem1 === (string) $elem2i.e. when the string representation is the same, the first element will be used.
注意：当且仅当
(string) $elem1 === (string) $elem2ie 当字符串表示相同时，才认为两个元素相等，则将使用第一个元素。
So make sure to implement the __toString()method in your class and that it outputs the same value for equal roles, e.g.
因此，请确保__toString()在您的类中实现该方法，并为相同的角色输出相同的值，例如
class Role {
private $name;
//.....
public function __toString() {
return $this->name;
}
}
This would consider two roles as equal if they have the same name.
如果两个角色具有相同的名称，这将认为它们是平等的。
回答by salathe
This answer uses in_array()since the nature of comparing objectsin PHP 5 allows us to do so. Making use of this object comparison behaviour requires that the array onlycontain objects, but that appears to be the case here.
这个答案之所以使用，是in_array()因为PHP 5中比较对象的性质允许我们这样做。使用这种对象比较行为要求数组只包含对象，但这里似乎就是这种情况。
$merged = array_merge($arr, $arr2);
$final = array();
foreach ($merged as $current) {
if ( ! in_array($current, $final)) {
$final[] = $current;
}
}
var_dump($final);
回答by yankee
Here is a way to remove duplicated objects in an array:
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);
回答by Remon
You can also serialize first:
您也可以先序列化：
$unique = array_map( 'unserialize', array_unique( array_map( 'serialize', $array ) ) );
As of PHP 5.2.9 you can just use optional sort_flag SORT_REGULAR:
从 PHP 5.2.9 开始，您可以只使用 optional sort_flag SORT_REGULAR：
$unique = array_unique( $array, SORT_REGULAR );
回答by Arvid Vermote
You can also use they array_filter function, if you want to filter objects based on a specific attribute:
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 []= $obj->getId();
return true;
});
回答by Silver Light
From here: http://php.net/manual/en/function.array-unique.php#75307
从这里：http: //php.net/manual/en/function.array-unique.php#75307
This one would work with objects and arrays also.
这个也适用于对象和数组。
<?php
function my_array_unique($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);
}
?>
回答by Kellen Mace
If you have an indexed array of objects, and you want to remove duplicates by comparing a specific property in each object, a function like the remove_duplicate_models()one below can be used.
如果您有一个对象的索引数组，并且希望通过比较每个对象中的特定属性来删除重复项，remove_duplicate_models()则可以使用如下所示的函数。
class Car {
private $model;
public function __construct( $model ) {
$this->model = $model;
}
public function get_model() {
return $this->model;
}
}
$cars = [
new Car('Mustang'),
new Car('F-150'),
new Car('Mustang'),
new Car('Taurus'),
];
function remove_duplicate_models( $cars ) {
$models = array_map( function( $car ) {
return $car->get_model();
}, $cars );
$unique_models = array_unique( $models );
return array_values( array_intersect_key( $cars, $unique_models ) );
}
print_r( remove_duplicate_models( $cars ) );
The result is:
结果是：
Array
(
[0] => Car Object
(
[model:Car:private] => Mustang
)
[1] => Car Object
(
[model:Car:private] => F-150
)
[2] => Car Object
(
[model:Car:private] => Taurus
)
)
回答by Artem Sivak
This is very simple solution:
这是非常简单的解决方案：
$ids = array();
foreach ($relate->posts as $key => $value) {
if (!empty($ids[$value->ID])) { unset($relate->posts[$key]); }
else{ $ids[$value->ID] = 1; }
}
回答by jricher
array_unique works by casting the elements to a string and doing a comparison. Unless your objects uniquely cast to strings, then they won't work with array_unique.
array_unique 的工作原理是将元素转换为字符串并进行比较。除非您的对象唯一地转换为字符串，否则它们将无法与 array_unique 一起使用。
Instead, implement a stateful comparison function for your objects and use array_filterto throw out things the function has already seen.
相反，为您的对象实现一个有状态的比较函数，并使用array_filter丢弃函数已经看到的东西。
