How to remove part of a string after last comma in PHP

Question

How to remove part of a string after last comma in PHP ?

String : "this is a post, number 1, date 23, month 04, year 2012"
Expected: "this is a post, number 1, date 23, month 04"

Answer 1

substr and strrpos would be useful

$until = substr($string, 0, strrpos($string.",", ","));

Note: edited based on comments below

Answer 2

You want to replace the last comma and the rest, that is a comma followed by any other character until the end of the string.

This can be formulated as a regular expression and that pattern can be replaced via preg_replace with an empty string:

$until = preg_replace('/,[^,]*$/', '', $string);

This is a variant of mario's answer that works in case there is no comma in the string as well.