Minus -
- is a native PHP operator, which allows subtraction on numbers, both integers and decimals, or produce the opposite of a number.
- silently triggers a conversion to a number, preferably integers, but otherwise decimal. It may produce a warning or a fatal error, if this is not possible.
It may also be repeated, with the pre- and post- increment operators.
It is the contrary to +.
<?php
$a = 2 - 1; // 1
$a = -$a; // -1
$a = -$a; // 1
--$a; // 0
$a--; // -1
?>