将以10为基数的数字转换为以62为基数的数字(a- za - 0-9)

I have a number in base 10. Is there anyway to translate it to a base 62?

我有一个以10为底的数。有没有办法把它转换成62底呢?

Example:

例子:

echo convert(12324324);
// returns Yg3 (fantasy example here)

PHP's base_convert() can convert up to base 36.

PHP的base_convert()可以转换为base 36。

9 个解决方案

#1

a quick and dirty solution can be to use a function like this:

一个快速而肮脏的解决方案可以是使用如下函数:

function toChars($number) {
   $res = base_convert($number, 10,26);
   $res = strtr($res,'0123456789','qrstuvxwyz');
   return $res;
}

The base convert translate your number to a base where the digits are 0-9a-p then you get rid of the remaining digits with a quick char substitution.

碱基转换把你的数字转换成一个0-9a-p的基数，然后你用一个快速的字符替换去掉剩下的数字。

As you may observe, the function is easily reversable.

正如您所看到的，这个函数很容易反转。

function toNum($number) {
   $res = strtr($number,'qrstuvxwyz','0123456789');
   $res = base_convert($number, 26,10);
   return $res;
}

By the way, what would you use this function for?

顺便问一下，这个函数的作用是什么?

Edit:

编辑:

Based on the question change and on the @jnpcl answer, a set of functions performs the base conversion without using pow and log (they take half times to complete the tests).

基于问题的改变和@jnpcl的回答，一组函数在不使用pow和log的情况下执行基本转换(完成测试需要花费一半的时间)。

The functions are working for integer values only

这些函数只适用于整数值

function toBase($num, $b=62) {
  $base='0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
  $r = $num  % $b ;
  $res = $base[$r];
  $q = floor($num/$b);
  while ($q) {
    $r = $q % $b;
    $q =floor($q/$b);
    $res = $base[$r].$res;
  }
  return $res;
}

function to10( $num, $b=62) {
  $base='0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
  $limit = strlen($num);
  $res=strpos($base,$num[0]);
  for($i=1;$i<$limit;$i++) {
    $res = $b * $res + strpos($base,$num[$i]);
  }
  return $res;
}

The test

测试

for ($i = 0; $i<1000000; $i++) {
  $x =  toBase($i);
  $y =  to10($x);
  if ($i-$y)
    echo "\n$i -> $x -> $y";
}

#2

http://us3.php.net/manual/en/function.base-convert.php#52450

http://us3.php.net/manual/en/function.base-convert.php # 52450

<?php
// Decimal > Custom
function dec2any( $num, $base=62, $index=false ) {
    if (! $base ) {
        $base = strlen( $index );
    } else if (! $index ) {
        $index = substr( "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ" ,0 ,$base );
    }
    $out = "";


    // this fix partially breaks when $num=0, but fixes the $num=238328 bug
    // also seems to break (adds a leading zero) at $num=226981 through $num=238327 *shrug*
    // for ( $t = floor( log10( $num ) / log10( $base - 1 ) ); $t >= 0; $t-- ) {

    // original code:
    for ( $t = floor( log10( $num ) / log10( $base ) ); $t >= 0; $t-- ) {
        $a = floor( $num / pow( $base, $t ) );
        $out = $out . substr( $index, $a, 1 );
        $num = $num - ( $a * pow( $base, $t ) );
    }
    return $out;
}
?>
Parameters:
$num - your decimal integer
$base - base to which you wish to convert $num (leave it 0 if you are providing $index or omit if you're using default (62))
$index - if you wish to use the default list of digits (0-1a-zA-Z), omit this option, otherwise provide a string (ex.: "zyxwvu")

<?php
// Custom > Decimal
function any2dec( $num, $base=62, $index=false ) {
    if (! $base ) {
        $base = strlen( $index );
    } else if (! $index ) {
        $index = substr( "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ", 0, $base );
    }
    $out = 0;
    $len = strlen( $num ) - 1;
    for ( $t = 0; $t <= $len; $t++ ) {
        $out = $out + strpos( $index, substr( $num, $t, 1 ) ) * pow( $base, $len - $t );
    }
    return $out;
}
?>
Parameters:
$num - your custom-based number (string) (ex.: "11011101")
$base - base with which $num was encoded (leave it 0 if you are providing $index or omit if you're using default (62))
$index - if you wish to use the default list of digits (0-1a-zA-Z), omit this option, otherwise provide a string (ex.: "abcdef")

#3

For big numbers, you might want to use the PHP BC library

对于较大的数字，您可能需要使用PHP BC库

function intToAny( $num, $base = null, $index = null ) {
    if ( $num <= 0 ) return '0';
    if ( ! $index )
        $index = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
    if ( ! $base )
        $base = strlen( $index );
    else
        $index = substr( $index, 0, $base );
    $res = '';
    while( $num > 0 ) {
        $char = bcmod( $num, $base );
        $res .= substr( $index, $char, 1 );
        $num = bcsub( $num, $char );
        $num = bcdiv( $num, $base );
    }
    return $res;
}

#4

function convertBase10ToBase62($num){
    $charset="0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
    $endChar=$charset[$num%62];
    $rtn="";

    if ( $num == "62" ) { 
        $rtn=$rtn.$charset[1]; 
    } else if ( $num >= 62 ) { 
        $rtn=$rtn.$charset[intval($num/62)%62+1]; 
    }

    $num=intval($num/62);

    while ($num > 61) {
        if ( is_int($num/62) == true ) { 
            $rtn=$rtn.$charset[0]; 
        } else { 
            $rtn=$rtn.$charset[$num%62]; 
        }

        $num=intval($num/62);
    }
    $rtn=$rtn.$endChar;
    echo "\n";
    echo $rtn;

    return $rtn;
}

#5

A simpler (and possibly faster) implementation that does not use pow nor log:

一种更简单(也可能更快)的实现，不使用pow或log:

function base62($num) {
  $index = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
  $res = '';
  do {
    $res = $index[$num % 62] . $res;
    $num = intval($num / 62);
  } while ($num);
  return $res;
}

#6

This function output the same than GNU Multiple Precision if possible…

如果可能，此函数输出与GNU的多重精度相同……

<?php

function base_convert_alt($val,$from_base,$to_base){
static $gmp;
static $bc;
static $gmp62;
if ($from_base<37) $val=strtoupper($val);
if ($gmp===null) $gmp=function_exists('gmp_init');
if ($gmp62===null) $gmp62=version_compare(PHP_VERSION,'5.3.2')>=0;
if ($gmp && ($gmp62 or ($from_base<37 && $to_base<37)))
return gmp_strval(gmp_init($val,$from_base),$to_base);
if ($bc===null) $bc=function_exists('bcscale');
$range='0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
if ($from_base==10)
$base_10=$val;
else
{
$n=strlen(($val="$val"))-++$ratio;
if ($bc) for($i=$n;$i>-1;($ratio=bcmul($ratio,$from_base)) && $i--)
$base_10=bcadd($base_10,bcmul(strpos($range,$val[$i]),$ratio));
else for($i=$n;$i>-1;($ratio*=$from_base) && $i--)
$base_10+=strpos($range,$val[$i])*$ratio;
}
if ($bc)
do $result.=$range[bcmod($base_10,$to_base)];
while(($base_10=bcdiv($base_10,$to_base))>=1);
else
do $result.=$range[$base_10%$to_base];
while(($base_10/=$to_base)>=1);
return strrev($to_base<37?strtolower($result):$result);
}


echo base_convert_alt('2661500360',7,51);

// Output Hello

#7

have an array of characters like:

拥有一系列字符，如:

$chars = array(
    1 => 'a',
    2 => 'b',
    //....
    27 => 'A',
    28 => 'B'
);

function getCharacter($key)
{
    if(array_key_exists($key, $chars[$key]))
        return $chars[$key];
    return false;
}

function getNumber($char)
{
    return array_search($char, $chars);
}

#8

It was hardly tested and works on real big product. Just copy this functions and use. If needed, you can arrange $baseChars sequentially, I need it for blended.

它几乎没有经过测试，而是在真正的大产品上工作。复制这个函数然后使用。如果需要，您可以按顺序安排$baseChars，我需要它用于混合。

    /**
     * decToAny converter
     * 
     * @param integer $num
     * @param string $baseChars
     * @param integer $base
     * @return string
     */
    function decToAny($num, $baseChars = '', $base = 62, $index = false) {

        $baseChars = empty($baseChars) ? 'HbUlYmGoAd0ScKq6Er5PuZp3OsQCh4RfNMtV8kJiLv9yXeI1aWgFj2zTx7DnBw' : $baseChars;
        if (!$base) {
            $base = strlen($index);
        } else if (!$index) {
            $index = substr($baseChars, 0, $base);
        }
        $out = "";

        for ($t = floor(log10($num) / log10($base)); $t >= 0; $t--) {
            $a = floor($num / pow($base, $t));
            $out = $out . substr($index, $a, 1);
            $num = $num - ( $a * pow($base, $t) );
        }

        return $out;
    }

Reverse method

相反的方法

    /**
     * anyTodec converter
     * 
     * @param string $num
     * @param string $baseChars
     * @param integer $base
     * @return string
     */
    function anyToDec($num, $baseChars = '', $base = 62, $index = false) {

        $baseChars = empty($baseChars) ? 'HbUlYmGoAd0ScKq6Er5PuZp3OsQCh4RfNMtV8kJiLv9yXeI1aWgFj2zTx7DnBw' : $baseChars;
        if (!$base) {
            $base = strlen($index);
        } else if (!$index) {
            $index = substr($baseChars, 0, $base);
        }
        $out = 0;
        $len = strlen($num) - 1;
        for ($t = 0; $t <= $len; $t++) {
            $out = $out + strpos($index, substr($num, $t, 1)) * pow($base, $len - $t);
        }
        return $out;
    }

#9

function convertBase10ToBase62($num){
$charset="0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
$rtn="";

$n=$num;$base=62;
while($n>0){
    $temp=$n%$base;
    $rtn=$charset[$temp].$rtn;
    $n=intval($n/$base);
}
 return $rtn;
}