The array_key_exists method can be used to check if a key/index is present in an array.
array_key_exists(string|int $key_to_check , array $array): bool
key_to_check – The key will be searched in the passed array. It can be an integer or string type.
array – The array that is searched for key_to_check.
This method returns true if the passed key is present in the array; otherwise, false is returned.
<?php$arr = array('one' => 1, 'two' => 2, 'three' => 3);echo "the array is \n";print_r($arr);echo array_key_exists('one', $arr) ? '"one" is present' : '"one" is not present';echo "\n";echo array_key_exists('four', $arr) ? '"four" is present' : '"four" is not present';?>
In the code above, we create an array:
$arr = array(
'one' => 1,
'two' => 2,
'three' => 3
);
array_key_exists('one', $arr)
We check if the key one is present in the created array by calling the array_key_exists method, with one and the created array as an argument. The key one is present in the passed array, so we will get true as a result.
array_key_exists('four', $arr)
We check if the key four is present in the array. In this case, we get false as a result because the key four is not present in the array.