What are the advantages of using ctype_digit() or regular expressions for validating numerical values in PHP?

When validating numerical values in PHP, using ctype_digit() is a simpler and more efficient way to check if a string contains only digits. It is a built-in function specifically designed for this purpose. On the other hand, using regular expressions can provide more flexibility and customization in validating numerical values, such as allowing certain formats or ranges.

// Using ctype_digit() to validate a numerical value
$value = "12345";
if (ctype_digit($value)) {
    echo "Valid numerical value";
} else {
    echo "Invalid numerical value";
}