How can the is_numeric function be used to determine if the first character of a string is a number in PHP?

To determine if the first character of a string is a number in PHP, you can use the `is_numeric` function along with `substr` to extract the first character of the string and check if it is numeric. By using these functions together, you can easily determine if the first character is a number or not.

$string = "123abc";
$firstChar = substr($string, 0, 1);
if (is_numeric($firstChar)) {
    echo "The first character is a number.";
} else {
    echo "The first character is not a number.";
}