What is the difference between is_numeric and ctype_digit functions in PHP when validating numbers?

When validating numbers in PHP, the main difference between is_numeric and ctype_digit functions is how they treat the input. is_numeric function considers a value as a number if it can be parsed as a numeric value, which means it can also be a float or in scientific notation. On the other hand, ctype_digit function specifically checks if the input consists of only digits (0-9) without any other characters. Therefore, if you want to validate that a value is a whole number without any decimal points or special characters, it is better to use ctype_digit.

// Using ctype_digit to validate if a value is a whole number
$value = "12345";
if (ctype_digit($value)) {
    echo "Valid whole number";
} else {
    echo "Not a valid whole number";
}