Can I generate 12345678.9 to 12,345,678.90?

Of course, there is a number_format function in PHP. The function prototype is as follows:
String number_format
(
Float number,
Int decimals,
String dec_point,
String thousands_sep
)
For example:
<?
$ Num = 12345678.9;
Echo number_format ($ num). '<br>'; // 4 homes and 5 homes
Echo number_format ($ num, 2). '<br> ';
Echo number_format ($ num, 2, ':'). '<br>'; // This method is incorrect.
Echo number_format ($ num, 2, ':', '-'). '<br> ';
?>
Output result:
12,345,679
12,345,678, 90
Warning: Wrong parameter count for number_format () in/data/homepage/test/number_format.php on line 5
12-345-678: 90