Question

Below is an old PHP function I have for a dropdown list for users to select there birthdate, this is just the day date portion of it, you can see that it uses str_pad to add on a 0 to the numbers 1-9, is there a better way of doing this?

<?PHP
$date_combo .= '<select name="' . $pre . 'day" class="' .$style. '">';
$date_combo .= "<option value=''>Day</option>";
for ($i = 1; $i <= 31; $i++) {
    $date_combo .= " <option ";
    if ($i == $selected_date_day) {
        $date_combo .= " selected ";
    }
    $date_combo .= " value='" . str_pad($i, 2, "0", STR_PAD_LEFT) . "'>" . str_pad($i, 2, "0", STR_PAD_LEFT) . "</option>";
}
$date_combo .= "</select> ";

echo $date_combo;
?>

Answer 1

An alternative to str_pad is to use sprintf.
The code:

str_pad($i, 2, "0", STR_PAD_LEFT)

becomes:

sprintf("%02d", $i)

It will print $i as an integer that is 2 characters wide and padded with zeros.
See the sprintf documentation.