What is the purpose of using empty() and isset() functions in PHP?

The purpose of using the empty() function in PHP is to check if a variable is empty or not. It returns true if the variable is empty (i.e., contains no value or is considered falsy), and false otherwise. On the other hand, the isset() function is used to check if a variable is set and is not null. It returns true if the variable exists and is not null, and false otherwise.

// Using empty() function to check if a variable is empty
$var = '';
if (empty($var)) {
    echo 'The variable is empty';
} else {
    echo 'The variable is not empty';
}

// Using isset() function to check if a variable is set
$var = null;
if (isset($var)) {
    echo 'The variable is set';
} else {
    echo 'The variable is not set';
}