What are common pitfalls when comparing variables in PHP, such as checking for empty values or matching passwords?

Common pitfalls when comparing variables in PHP include not properly checking for empty values, not using strict comparison operators, and not securely comparing passwords (e.g., storing plaintext passwords). To avoid these pitfalls, always check for empty values using functions like empty() or isset(), use strict comparison operators (=== and !==) for accurate comparisons, and securely hash and compare passwords using functions like password_hash() and password_verify().

// Checking for empty values
if (!empty($variable)) {
    // do something
}

// Using strict comparison operators
if ($variable === $anotherVariable) {
    // do something
}

// Securely comparing passwords
$hashedPassword = password_hash($password, PASSWORD_DEFAULT);

if (password_verify($inputPassword, $hashedPassword)) {
    // passwords match
} else {
    // passwords do not match
}