How to Delete Array Element by Key in PHP

In this short article, we’ll look at a couple of examples of removing array elements by their key.

Full code listing below:

$array = [
	1 => 'One',
	'Two' => 3,
	'Three' => 'Three',
	4 => NULL,
];
echo "<pre dir='ltr'>";print_r($array); echo "</pre>";

if(isset($array['Two']))
{
	unset($array['Two']);
}
echo "<pre dir='ltr'>";print_r($array); echo "</pre>";

if(isset($array[4]))
{
	unset($array[4]);
}
echo "<pre dir='ltr'>";print_r($array); echo "</pre>";

if(array_key_exists(4, $array))
{
	unset($array[4]);
}
echo "<pre dir='ltr'>";print_r($array); echo "</pre>";

Here’s what we have:

$array = [
	1 => 'One',
	'Two' => 3,
	'Three' => 'Three',
	4 => NULL,
];
echo "<pre dir='ltr'>";print_r($array); echo "</pre>";

Initialization of an array with four values (pay attention to the last one).

Removing an array element by key is no different than deleting a regular variable. To do this, you need to use PHP’s `unset()` function, passing the variable to be deleted as the argument. But before deleting anything, it's a good practice to check whether the variable has been initialized. Otherwise, an error may occur.

To check this, you can use the following condition:

if(isset($array['Two']))
{
	unset($array['Two']);
}
echo "<pre dir='ltr'>";print_r($array); echo "</pre>";

and immediately verify the result. As you can see, the array has been reduced by one record.

Let’s continue our test and try to remove the element with key `4`:

if(isset($array[4]))
{
	unset($array[4]);
}
echo "<pre dir='ltr'>";print_r($array); echo "</pre>";

After checking the result, we find that the value hasn’t been deleted. The issue lies in the conditional operator and the `isset()` function. The thing is, `isset()` doesn’t return true for a variable that has a `NULL` value. That’s why in such cases, it’s better to use the `array_key_exists()` function:

if(array_key_exists(4, $array))
{
	unset($array[4]);
}
echo "<pre dir='ltr'>";print_r($array); echo "</pre>";

We check the result — yes, everything is fine, the value was removed.