Метод 1: использование функции unset()

$array = ['key1' => 'value1', 'key2' => 'value2', 'key3' => 'value3'];
// Unset an element by key name
unset($array['key2']);
print_r($array);

Выход:

Array
(
    [key1] => value1
    [key3] => value3
)

Метод 2: использование функции array_diff_key()

$array = ['key1' => 'value1', 'key2' => 'value2', 'key3' => 'value3'];
// Unset an element by key name
$array = array_diff_key($array, ['key2' => '']);
print_r($array);

Выход:

Array
(
    [key1] => value1
    [key3] => value3
)

Метод 3: использование функции array_filter()

$array = ['key1' => 'value1', 'key2' => 'value2', 'key3' => 'value3'];
// Unset an element by key name
$array = array_filter($array, function ($key) {
    return $key !== 'key2';
}, ARRAY_FILTER_USE_KEY);
print_r($array);

Выход:

Array
(
    [key1] => value1
    [key3] => value3
)

Метод 4. Использование функции array_splice()

$array = ['key1' => 'value1', 'key2' => 'value2', 'key3' => 'value3'];
// Unset an element by key name
array_splice($array, array_search('key2', array_keys($array)), 1);
print_r($array);

Выход:

Array
(
    [key1] => value1
    [key3] => value3
)