PHP implements conversion between various bases_PHP tutorial

There is such a requirement in the project, which is to convert decimal to binary, octal, and hexadecimal, and also convert binary, octal, and hexadecimal to decimal. Record it below so that it can be used easily in the future. Pick it up.

To convert from decimal to other bases, just divide the number by the base number to be converted and read the remainder. Just connect them together. The following is the conversion of decimal to binary, octal, and hexadecimal:

<?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 $bin 转换的进制可以是：2,8,16
 * @return array 返回数据 array() 返回没有数据转换的格式
 * @copyright chengmo QQ:8292669
 */
function decto_bin($datalist,$bin)
{
    static $arr=array(0,1,2,3,4,5,6,7,8,9,'A','B','C','D','E','F');
    if(!is_array($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;
} 

The test results are as follows:

var_dump(decto_bin(array(128,253),2));
var_dump(decto_bin(array(128,253),8));
var_dump(decto_bin(array(128,253),16));
 
X-Powered-By: PHP/5.2.0
Content-type: text/html
array(2) {
  [0]=>
  string(8) "10000000"
  [1]=>
  string(8) "11111101"
}
array(2) {
  [0]=>
  string(4) "0200"
  [1]=>
  string(4) "0375"
}
array(2) {
  [0]=>
  string(2) "80"
  [1]=>
  string(2) "FD"
}

Use multiplication to convert binary, octal and hexadecimal to decimal, for example: 1101 to decimal: 1*2^3+1*2^2+0*2^1+1*2^0, the program design is as follows:

<?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 $bin 转换的进制可以是：2,8,16
 * @return array 返回数据 array() 返回没有数据转换的格式
 * @copyright chengmo QQ:8292669
 */
function bin_todec($datalist,$bin)
{
    static $arr=array('0'=>0,'1'=>1,'2'=>2,'3'=>3,'4'=>4,'5'=>5,
	'6'=>6,'7'=>7,'8'=>8,'9'=>9,'A'=>10,'B'=>11,'C'=>12,'D'=>13,'E'=>14,'F'=>15);
    if(!is_array($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;
}

The test is as follows:

var_dump(bin_todec(array('ff','ff33','cc33'),16));
var_dump(bin_todec(array('1101101','111101101'),2));
var_dump(bin_todec(array('1234123','12341'),8));
 
X-Powered-By: PHP/5.2.0
Content-type: text/html
array(3) {
  [0]=>
  int(255)
  [1]=>
  int(65331)
  [2]=>
  int(52275)
}
array(2) {
  [0]=>
  int(124)
  [1]=>
  int(508)
}
array(2) {
  [0]=>
  int(342099)
  [1]=>
  int(5345)
}

These are just implementation methods. In fact, it doesn’t matter whether it is PHP language or other languages, the implementation ideas are the same. PHP actually has many built-in functions to complete these contents: bindec(), decoct(), dechex() base_convert() decbin() This is just an implementation idea.

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