How to Check key exists in a PHP array?

PHP has two inbuilt functions array_key_exists() & key_exists(), and with the help of these functions you can check whether a key exists in an array or not.

The key_exists() function is alias of array_key_exists(). Both do the same thing.

PHP array_key_exists() function

array_key_exists(key, array)

• This function takes two parameters, the key you want to find and the array where you want to search.
• It will return true if the given key is present in the array, else it will return false.

<?php
$marks = [
    "John" => 75,
    "Mark" => 62,
    "Smith" => 58,
    "Jane" => 87
];

if(array_key_exists("Smith", $marks)){
    echo "The key exists in the array";
}
else{
    echo "The key is not in the array";
}

The key exists in the array