Extract a property from an array of objects in PHP

In PHP, you can extract a specific property from an array of objects using several methods. This is useful when you need to get all values of a particular property from multiple objects.

Sample Data

Let's start with an array of objects containing ID properties −

<?php
$my_object = array(
    (object) ['id' => 12],
    (object) ['id' => 33],
    (object) ['id' => 59]
);

print_r($my_object);
?>

Array
(
    [0] => stdClass Object
        (
            [id] => 12
        )

    [1] => stdClass Object
        (
            [id] => 33
        )

    [2] => stdClass Object
        (
            [id] => 59
        )

)

Using array_column() (PHP 5.5+)

The array_column() function is the most efficient method for extracting a property −

<?php
$my_object = array(
    (object) ['id' => 12],
    (object) ['id' => 33],
    (object) ['id' => 59]
);

$object_id = array_column($my_object, 'id');
print_r($object_id);
?>

Array
(
    [0] => 12
    [1] => 33
    [2] => 59
)

Using array_map() with Anonymous Function

For more complex extraction logic, use array_map() with an anonymous function −

<?php
$my_object = array(
    (object) ['id' => 12],
    (object) ['id' => 33],
    (object) ['id' => 59]
);

$object_id = array_map(function($obj) {
    return $obj->id;
}, $my_object);

print_r($object_id);
?>

Array
(
    [0] => 12
    [1] => 33
    [2] => 59
)

Using foreach Loop

A traditional approach using a foreach loop for maximum control −

<?php
$my_object = array(
    (object) ['id' => 12],
    (object) ['id' => 33],
    (object) ['id' => 59]
);

$object_id = array();
foreach ($my_object as $obj) {
    $object_id[] = $obj->id;
}

print_r($object_id);
?>

Array
(
    [0] => 12
    [1] => 33
    [2] => 59
)

Comparison

Conclusion

Use array_column() for simple property extraction as it's the most efficient. For complex logic or older PHP versions, use array_map() or foreach loops.