What are the best practices for handling numeric input validation in PHP?

When handling numeric input validation in PHP, it is important to ensure that the input is indeed a numeric value and to prevent any potential security vulnerabilities such as SQL injection attacks. One way to validate numeric input is by using PHP's built-in functions like is_numeric() or is_int() to check if the input is a valid number. Additionally, you can sanitize the input using functions like filter_var() with the FILTER_SANITIZE_NUMBER_INT flag to remove any non-numeric characters.

// Validate numeric input
$input = $_POST['numeric_input'];

if (is_numeric($input)) {
    // Input is a valid number
    $numeric_value = filter_var($input, FILTER_SANITIZE_NUMBER_INT);
    echo "Numeric value: " . $numeric_value;
} else {
    // Input is not a valid number
    echo "Invalid numeric input";
}