Detailed explanation of code and function examples on how to implement conversion between several hexadecimal systems in PHP

1, decimal conversion

1, decimal to binary decbin() function, the following example

echo decbin(12); //输出 1100 
echo decbin(26); //输出 11010

decbin
(PHP 3, PHP 4, PHP 5)
decbin -- Convert decimal to binary
Description
string decbin (int number)
Return one String , containing the binary representation of the given number parameter. The maximum value that can be converted is 4294967295 in decimal, which results in a string of 32 ones.

2, decimal to octal decoct() function

echo decoct(15); //输出 17 
echo decoct(264); //输出 410

decoct
(PHP 3, PHP 4, PHP 5)
decoct -- Convert decimal to octal
Description
string decoct (int number)
Returns a string containing the octal representation of the given number parameter. The maximum value that can be converted is 4294967295 in decimal, which results in "37777777777".

3, convert decimal to hexadecimal dechex() function

echo dechex(10); //输出 a 
echo dechex(47); //输出 2f

dechex
(PHP 3, PHP 4, PHP 5)
dechex -- decimal conversion For hexadecimal
Description
string dechex (int number)
Returns a string containing the hexadecimal representation of the given number parameter. The maximum value that can be converted is 4294967295 in decimal, which results in "ffffffff".

<?php 
/** 
*十进制转二进制、八进制、十六进制 不足位数前面补零* 
* 
* @param array $datalist 传入数据array(100,123,130) 
* @param int $bin 转换的进制可以是：2,8,16 
* @return array 返回数据 array() 返回没有数据转换的格式 
*/ 
function decto_bin($datalist,$bin) 
{ 
static $arr=array(0,1,2,3,4,5,6,7,8,9,&#39;A&#39;,&#39;B&#39;,&#39;C&#39;,&#39;D&#39;,&#39;E&#39;,&#39;F&#39;); 
if(!is_array($datalist)) $datalist=array($datalist); 
if($bin==10)return $datalist; //相同进制忽略 
$bytelen=ceil(16/$bin); //获得如果是$bin进制，一个字节的长度 
$aOutChar=array(); 
foreach ($datalist as $num) 
{ 
$t=""; 
$num=intval($num); 
if($num===0)continue; 
while($num>0) 
{ 
$t=$arr[$num%$bin].$t; 
$num=floor($num/$bin); 
} 
$tlen=strlen($t); 
if($tlen%$bytelen!=0) 
{ 
$pad_len=$bytelen-$tlen%$bytelen; 
$t=str_pad("",$pad_len,"0",STR_PAD_LEFT).$t; //不足一个字节长度，自动前面补充0 
} 
$aOutChar[]=$t; 
} 
return $aOutChar; 
}

2. Binary conversion

1, Binary to hexadecimal conversion bin2hex() function

$binary = "11111001"; 
$hex = dechex(bindec($binary)); 
echo $hex;//输出f9

bin2hex
(PHP 3 >= 3.0.9, PHP 4, PHP 5)
bin2hex -- Convert binary data to hexadecimal representation
Description
string bin2hex ( string str )
Returns the ASCII string, which is the hexadecimal representation of the parameter str. Conversion uses byte mode, with the high nibble taking precedence.

2, binary to decimal conversion bindec() function

echo bindec('110011'); //输出 51 
echo bindec('000110011'); //输出 51 
echo bindec('111'); //输出 7

bindec
(PHP 3, PHP 4, PHP 5)
bindec -- Binary conversion to Decimal
Description
number bindec (string binary_string)
Returns the decimal equivalent of the binary number represented by the binary_string parameter.
bindec() Converts a binary number to an integer. The largest number that can be converted is 31 digits, or 2147483647 in decimal. Starting with PHP 4.1.0, this function can handle large values, in which case it returns a float type.

<?php 
/** 
*二进制、八进制、十六进制 转十进制* 
* 
* @param array $datalist 传入数据array(df,ef) 
* @param int $bin 转换的进制可以是：2,8,16 
* @return array 返回数据 array() 返回没有数据转换的格式 
*/ 
function bin_todec($datalist,$bin) 
{ 
static $arr=array(&#39;0&#39;=>0,&#39;1&#39;=>1,&#39;2&#39;=>2,&#39;3&#39;=>3,&#39;4&#39;=>4,&#39;5&#39;=>5,&#39;6&#39;=>6,&#39;7&#39;=>7,&#39;8&#39;=>8,&#39;9&#39;=>9,&#39;A&#39;=>10,&#39;B&#39;=>11,&#39;C&#39;=>12,&#39;D&#39;=>13,&#39;E&#39;=>14,&#39;F&#39;=>15); 
if(!is_array($datalist))$datalist=array($datalist); 
if($bin==10)return $datalist; //为10进制不转换 
$aOutData=array(); //定义输出保存数组 
foreach ($datalist as $num) 
{ 
$atnum=str_split($num); //将字符串分割为单个字符数组 
$atlen=count($atnum); 
$total=0; 
$i=1; 
foreach ($atnum as $tv) 
{ 
$tv=strtoupper($tv); 
if(array_key_exists($tv,$arr)) 
{ 
if($arr[$tv]==0)continue; 
$total=$total+$arr[$tv]*pow($bin,$atlen-$i); 
} 
$i++; 
} 
$aOutData[]=$total; 
} 
return $aOutData; 
}

Three, octal conversion

Octal to decimal octdec() function

echo octdec('77'); //输出 63 
echo octdec(decoct(45)); //输出 45

octdec
(PHP 3, PHP 4, PHP 5)
octdec -- Convert octal to decimal
Description
number octdec (string octal_string)
Returns the decimal form of the octal number represented by the octal_string parameter, etc. value. The largest value that can be converted is 17777777777 or 2147483647 in decimal. Starting with PHP 4.1.0, this function can handle large numbers, in which case it returns a float type.

Four, hexadecimal conversion

Hexadecimal to decimal hexdec() function

var_dump(hexdec("See")); 
var_dump(hexdec("ee")); 
// both print "int(238)" 
var_dump(hexdec("that")); // print "int(10)" 
var_dump(hexdec("a0")); // print "int(160)"

hexdec
(PHP 3, PHP 4, PHP 5)
hexdec -- Convert hexadecimal to decimal
Description
number hexdec (string hex_string)
Returns the same as hex_string The decimal equivalent of the hexadecimal number represented by the parameter. hexdec() Converts a hexadecimal string to a decimal number. The maximum value that can be converted is 7ffffffff, which is 2147483647 in decimal. Starting with PHP 4.1.0, this function can handle large numbers, in which case it returns a float type.
hexdec() Replaces all non-hexadecimal characters encountered with 0. This way, all zeros on the left are ignored, but zeros on the right are included in the value.

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