What is the difference between using isset and array_key_exists in PHP?

The main difference between using isset and array_key_exists in PHP is that isset checks if a variable is set and is not null, while array_key_exists checks if a specific key exists in an array. If you want to check if a key exists in an array, you should use array_key_exists. If you want to check if a variable is set and not null, you should use isset. 

// Using isset to check if a variable is set and not null
$variable = null;
if (isset($variable)) {
    echo 'Variable is set and not null';
} else {
    echo 'Variable is not set or is null';
}

// Using array_key_exists to check if a key exists in an array
$array = array('key' => 'value');
if (array_key_exists('key', $array)) {
    echo 'Key exists in the array';
} else {
    echo 'Key does not exist in the array';
}

Keywords

PHP isset array_key_exists difference comparison

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