How to Remove Duplicate Objects from an Array in PHP?

How to Remove Duplicate Objects from an Array in PHP

The array_unique() function can identify and eliminate duplicate elements from an array. However, this functionality may not be immediately apparent for arrays containing objects. To effectively remove duplicate objects, certain modifications are necessary.

Solution Using SORT_REGULAR

To enable array_unique() to work correctly with objects, specify the SORT_REGULAR flag as the second parameter:

<code class="php"><?php 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));
?></code>

Output:

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

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

Explanation

By using SORT_REGULAR, the array_unique() function essentially compares the prop property of each object, treating objects with identical property values as duplicates.

Caution

While this method effectively removes duplicate objects, it's important to note that it relies on the == comparison rather than the stricter === comparison. This means that objects with different identities but identical properties will still be considered duplicates.

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