Hexadecimal Integer
Hexadecimal integers are integers with an hexadecimal representation. Their value is the same, yet their are written in a different way than the common decimal.
Hexadecimal has native support with the 0x123 format. There is also support for hexadecimal characters, inside double-quote strings, with the \xhh syntax.
There are functions to convert from and to hexadecimal format: hexdec(), dechex() and base_convert(), from ten to sixteen, and then, with an arbitrary base, up to 36.
PHP also has special syntax for binary and octal numbers.
<?php
$twenty = 0x14;
$twentyToo = 20;
$i = "\x69"; // i is the 105 ASCII code
$i = 'i';
?>