In what situations would using array_key_exists() be preferred over isset() in PHP?

array_key_exists() should be preferred over isset() in PHP when you specifically want to check if a key exists in an array, regardless of its value (even if the value is null). isset() will return false if the key exists but its value is null, while array_key_exists() will return true in that case. 

// Using array_key_exists() to check if a key exists in an array
$array = ['key' => null];

if (array_key_exists('key', $array)) {
    echo 'Key exists in the array';
} else {
    echo 'Key does not exist in the array';
}

Keywords

array_key_exists isset PHP arrays comparison

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