decbin()
decbin() is a PHP native function that converts a decimal integer to its binary string representation.
decbin() takes a single integer argument and returns a string of 0 and 1 characters, without any 0b prefix. Negative numbers are converted using the 32-bit or 64-bit two’s complement representation, depending on the platform, which produces a long string of ones.
The reverse operation is bindec(), which converts a binary string back to a decimal number. Related functions convert to and from other bases: dechex() and hexdec() for hexadecimal, decoct() and octdec() for octal. base_convert() handles arbitrary bases.
<?php
echo decbin(12); // 1100
echo decbin(26); // 11010
echo decbin(-1); // 1111111111111111111111111111111111111111111111111111111111111111 (on 64-bit)
?>