What is PHP hex2bin() Function?
If you want to decode a encoded hexadecimal string back to its binary representation (which translates to ASCII value), use hex2bin() function.
How PHP hex2bin() Function works?
The function considers characters in a string as hexadecimal characters and process two characters at a time and converts this to 1 byte binary data.
Syntax:
hex2bin(string)
Parameters:
The Function has 1 parameter which is required –
string (Required): It specifies a string that represents a hexadecimal value.
Return Values:
aaa
Examples:
Example 1:
<?php
$hex = "41";
echo "Binary representation of the hexadecimal $hex is: " . hex2bin($hex);
?>
Output:
Binary representation of the hexadecimal 41 is: A
Notes on hex2bin() Function:
- The function doesn’t convert a hexadecimal number to binary number. Look at the example below. The binary of the hexadecimal 41 is 01000001. But, the function converts it to “A”, because, it processes the 2 digits at a time, not process separately.
<?php echo hex2bin("41"); ?>Output:
A
- If you want to convert a hexadecimal number to its binary number, use base_convert() function-
<?php $hex = "41"; echo "Binary number of the hexadecimal $hex is: " . base_convert($hex, 16, 2); ?>
Output:
Binary number of the hexadecimal 41 is: 1000001
Caution:
- If the input string’s length is odd, the function generates a warning-
<?php $hex = "414"; echo "Binary representation of the hexadecimal $hex is: " . hex2bin($hex); ?>
Output:
Warning: hex2bin(): Hexadecimal input string must have an even length in …\ hex2bin.php on line 3
Binary representation of the hexadecimal 414 is: - If the input has any invalid hexadecimal number, the function generates a warning-
<?php $hex = "$4"; echo "Binary representation of the hexadecimal $hex is: " . hex2bin($hex); ?>
Output:
Warning: hex2bin(): Input string must be hexadecimal string in …\hex2bin.php on line 3
Binary representation of the hexadecimal $4 is:Explanation:
Valid hexadecimal characters are – 0 1 2 3 4 5 6 7 8 9 a b c d e f. Here, $ is not a valid hexadecimal character.
PHP Version Support:
PHP 4, PHP 5, PHP 7, PHP 8
Summary: PHP hex2bin() Function
Hex2bin() function is one of the built-in string functions. Use this function to decode an encoded hexadecimal value to its binary representation.