Remove duplicates from an array based on object property?
duplicates, multidimensional-array, object, php
Solution
For `php >=7.0`:
Since `array_column` works on object-arrays since PHP 7.0 you can use the following combination as suggested by @plashenkov:
$filtered = array_intersect_key($array, array_unique(array_column($array, 'someProperty')));
Full example: 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);
Output:
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
)
)
The object with term_id 15 was removed as it had the same name as term_id 14.
For `php <7.0`:
Build a new array with the existing keys and just the name as value, use `array_unique` (note that it preserves keys).
Then copy every key from the original array to a new array (`$filtered`) (or remove everything thats not in the unique'ed array from the original key-wise).
Edit: Complete example: 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);
Output:
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
)
)
The object with term_id 15 was removed as it had the same name as term_id 14.
Problem
I have an array of objects. I'd like to remove the duplicates based on the "name" value in the object. ``` [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" } ``` So in this case, how do I remove the duplicate "Campaign Finance" object from the array. So the entire [2] object? I've gone through a bunch of the PHP duplicate array question here, but none seemed to deal with objects and filtering just off of one parameter.