How to convert hexadecimal to corresponding characters in php

PHP provides a function for converting hexadecimal characters, which can easily convert hexadecimal strings into corresponding characters. This article will introduce the usage and precautions of this function.

1. Function introduction

PHP provides two functions that can be used to convert hexadecimal strings into characters:

1. hex2bin() function : Convert hexadecimal string to binary string.
2. pack() function: Pack one or more integers, floating point numbers or strings into a binary string.

2. Usage of hex2bin() function

Syntax: hex2bin($hexstr)

Function: Convert a hexadecimal string to the corresponding Binary string.

Sample code:

$hexstr = '616263';
$binstr = hex2bin($hexstr);
echo $binstr;

Output result:

abc

3. Usage of pack() function

Syntax: pack($format, $data1, $data2, ...)

Role: Pack one or more integers, floating point numbers or strings into a binary string.

$format parameter: Specify the packaging format, see the table below for details.

##aNUL padding characters StringASpace-filled stringhHexadecimal string (low digit First)HHexadecimal string (highest order first)cSigned charactersxFill 1 byte blank##CsSnviIlLNVfdSample code:

Format	Description
Unsigned characters
Signed short (16 bits, endian depends on host)
Unsigned short integer (16 bits, big and small endian depends on the host)
Unsigned short integer (16 bits, big endian)
Unsigned short (16 bits, little endian)
Signed integer type (32 bits, big and small endian depends on the host)
Unsigned integer type (32 bits, big and small endian depends on the host)
Signed long integer (32 bits, endian depends on the host)
Unsigned long integer (32 bits, big and small endian depends on the host)
Unsigned long integer (32 bits, big endian) order)
Unsigned long integer (32 bits, little endian)
Single precision floating point number
Double precision floating point number

$hexstr = '616263';
$binstr = pack('H*', $hexstr);
echo $binstr;

Output result:

abc

4. Notes

hex2bin() function and pack() function are only supported by PHP5.4 and above.

1. The parameters of the hex2bin() function and pack() function must be hexadecimal strings with an even number of digits, otherwise an error will be reported.
2. The first parameter of the pack() function must specify the packaging format, and generally the endianness needs to be selected based on the target encoding.

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