base_convert

(PHP 4, PHP 5, PHP 7, PHP 8)

base_convert — Convertir un número entre bases arbitrarias

Descripción

base_convert(string $number, int $frombase, int $tobase): string

Devuelve una cadena que contiene el número dado por number representado en base tobase. La base en la cual es dado number es especificada en frombase. Tanto frombase como tobase tienen que ser valores entre 2 y 36, inclusive. Los dígitos en números con una base mayor que 10 serán representados con las letras a-z, en donde a significa 10, b significa 11 y z significa 35. No importa si las letras son mayúsculas o minúsculas: number se interpretará correctamente.

Advertencia

base_convert() puede perder precisión en números grandes debido a las propiedades relacionadas con el tipo interno "double" o "flotante" usado. Por favor, consulte la sección sobre Números de punto flotante del manual para información más específica y limitaciones.

Parámetros

number: El número a convertir. Cualquier carácter inválido en number será ignorado silenciosamente.
frombase: La base en que se encuentra number
tobase: La base a la cual convertir number

Valores devueltos

number convertido a base tobase

Ejemplos

Ejemplo #1 Ejemplo de base_convert()


<?php
$hexadecimal = 'a37334';
echo base_convert($hexadecimal, 16, 2);
?>

El resultado del ejemplo sería:

101000110111001100110100

Ver también

intval() - Obtiene el valor entero de una variable

＋add a note

User Contributed Notes 25 notes

down

PHPCoder at niconet2k dot com ¶

10 years ago


Convert an arbitrarily large number from any base to any base.

string convBase(string $numberInput, string $fromBaseInput, string $toBaseInput)
$numberInput number to convert as a string
$fromBaseInput base of the number to convert as a string
$toBaseInput base the number should be converted to as a string
examples for $fromBaseInput and $toBaseInput
'0123456789ABCDEF' for Hexadecimal (Base16)
'0123456789' for Decimal (Base10)
'01234567' for Octal (Base8)
'01' for Binary (Base2) 
You can really put in whatever you want and the first character is the 0.
Examples:

<?php 
convBase('123', '0123456789', '01234567'); 
//Convert '123' from decimal (base10) to octal (base8).
//result: 173

convBase('70B1D707EAC2EDF4C6389F440C7294B51FFF57BB', '0123456789ABCDEF', '01');
//Convert '70B1D707EAC2EDF4C6389F440C7294B51FFF57BB' from hexadecimal (base16) to binary (base2).
//result: 
//111000010110001110101110000011111101010110000101110
//110111110100110001100011100010011111010001000000110
//001110010100101001011010100011111111111110101011110
//111011

convBase('1324523453243154324542341524315432113200203012', '012345', '0123456789ABCDEF');
//Convert '1324523453243154324542341524315432113200203012' from senary (base6) to hexadecimal (base16).
//result: 1F9881BAD10454A8C23A838EF00F50

convBase('355927353784509896715106760','0123456789','Christopher');
//Convert '355927353784509896715106760' from decimal (base10) to undecimal (base11) using "Christopher" as the numbers.
//result: iihtspiphoeCrCeshhorsrrtrh

convBase('1C238Ab97132aAC84B72','0123456789aAbBcCdD', '~!@#$%^&*()');
//Convert'1C238Ab97132aAC84B72' from octodecimal (base18) using '0123456789aAbBcCdD' as the numbers to undecimal (base11) using '~!@#$%^&*()' as the numbers.
//result: !%~!!*&!~^!!&(&!~^@#@@@&

function convBase($numberInput, $fromBaseInput, $toBaseInput)
{
    if ($fromBaseInput==$toBaseInput) return $numberInput;
    $fromBase = str_split($fromBaseInput,1);
    $toBase = str_split($toBaseInput,1);
    $number = str_split($numberInput,1);
    $fromLen=strlen($fromBaseInput);
    $toLen=strlen($toBaseInput);
    $numberLen=strlen($numberInput);
    $retval='';
    if ($toBaseInput == '0123456789')
    {
        $retval=0;
        for ($i = 1;$i <= $numberLen; $i++)
            $retval = bcadd($retval, bcmul(array_search($number[$i-1], $fromBase),bcpow($fromLen,$numberLen-$i)));
        return $retval;
    }
    if ($fromBaseInput != '0123456789')
        $base10=convBase($numberInput, $fromBaseInput, '0123456789');
    else
        $base10 = $numberInput;
    if ($base10<strlen($toBaseInput))
        return $toBase[$base10];
    while($base10 != '0')
    {
        $retval = $toBase[bcmod($base10,$toLen)].$retval;
        $base10 = bcdiv($base10,$toLen,0);
    }
    return $retval;
}
?>

down

Anonymous ¶

3 years ago


While not immediately clear from the description above, a negative sign is also "silently ignored".

base_convert("-12", 10, 10)   =>   12

down

JR ¶

11 years ago


Short arabic2roman conveter:



<?php

function rome($N){

        $c='IVXLCDM';

        for($a=5,$b=$s='';$N;$b++,$a^=7)

                for($o=$N%$a,$N=$N/$a^0;$o--;$s=$c[$o>2?$b+$N-($N&=-2)+$o=1:$b].$s);

        return $s;

}

?>



And it works :)

down

Clifford dot ct at gmail dot com ¶

10 years ago


If you use base_convert to convert a large (eg. 80-bit) hexadecimal to base-36, you might observe:



ABCDEF00001234567890 (hexadecimal) => 3O47RE02JZSW0KS8 (base-36) => ABCDEF00001240000000 (hexadecimal)



This is normal and is due to the loss of precision on large numbers.



I have written a string-based function using the built-in BC Math Extension which will overcome this and similar problems.



<?php



function str_baseconvert($str, $frombase=10, $tobase=36) {

    $str = trim($str);

    if (intval($frombase) != 10) {

        $len = strlen($str);

        $q = 0;

        for ($i=0; $i<$len; $i++) {

            $r = base_convert($str[$i], $frombase, 10);

            $q = bcadd(bcmul($q, $frombase), $r);

        }

    }

    else $q = $str;

 

    if (intval($tobase) != 10) {

        $s = '';

        while (bccomp($q, '0', 0) > 0) {

            $r = intval(bcmod($q, $tobase));

            $s = base_convert($r, 10, $tobase) . $s;

            $q = bcdiv($q, $tobase, 0);

        }

    }

    else $s = $q;

 

    return $s;

}



?>



Typical use-cases:

1.  Convert a large arbitrary precision number to base-36.

2.  Convert a 32-char hexadecimal UUID (128-bit) to a 25-char base-36 unique key, and vice versa.



Examples:



<?php

$b16 = 'ABCDEF00001234567890';

$b36 = str_baseconvert($b16, 16, 36);

echo ("$b16 (hexadecimal) = $b36 (base-36) \\n");



$uuid = 'ABCDEF01234567890123456789ABCDEF';

$ukey = str_baseconvert($uuid, 16, 36);

echo ("$uuid (hexadecimal) = $ukey (base-36) \\n");

?>



ABCDEF00001234567890 (hexadecimal) = 3o47re02jzqisvio (base-36) 

ABCDEF01234567890123456789ABCDEF (hexadecimal) = a65xa07491kf5zyfpvbo76g33 (base-36)

down

lindsay at bitleap dot com ¶

17 years ago


If you need to use base_convert with numbers larger then 32 bit, the following gmp implementation of base_convert should work.

<?php

/*use gmp library to convert base. gmp will convert numbers > 32bit*/
function gmp_convert($num, $base_a, $base_b)
{
        return gmp_strval ( gmp_init($num, $base_a), $base_b );
}

?>

down

Theriault ¶

12 years ago


If you would like to convert numbers into just the uppercase alphabet base and vice-versa (e.g. the column names in a Microsoft Windows Excel sheet..A-Z, AA-ZZ, AAA-ZZZ, ...), the following functions will do this.

<?php

/**
 * Converts an integer into the alphabet base (A-Z).
 *
 * @param int $n This is the number to convert.
 * @return string The converted number.
 * @author Theriault
 * 
 */
function num2alpha($n) {
    $r = '';
    for ($i = 1; $n >= 0 && $i < 10; $i++) {
        $r = chr(0x41 + ($n % pow(26, $i) / pow(26, $i - 1))) . $r;
        $n -= pow(26, $i);
    }
    return $r;
}
/**
 * Converts an alphabetic string into an integer.
 *
 * @param int $n This is the number to convert.
 * @return string The converted number.
 * @author Theriault
 * 
 */
function alpha2num($a) {
    $r = 0;
    $l = strlen($a);
    for ($i = 0; $i < $l; $i++) {
        $r += pow(26, $i) * (ord($a[$l - $i - 1]) - 0x40);
    }
    return $r - 1;
}

?>

Microsoft Windows Excel stops at IV (255), but this function can handle much larger. However, English words will start to form after a while and some may be offensive, so be careful.

down

AdamJacobMuller at AdamJacobMuller dot com ¶

18 years ago


<?php

function binarycodedstring2dec($binary) {

        $len=strlen($binary);

        $rows=($len/4)-1;

        if (($len%4)>0) {

                $pad=$len+(4-($len%4));

                $binary=str_pad($binary,$pad,"0",STR_PAD_LEFT);

                $len=strlen($binary);

                $rows=($len/4)-1;

        }

        $x=0;

        for ($x=0;$x<=$rows;$x++) {

                $s=($x*4);

                $bins=$binary[$s].$binary[$s+1].$binary[$s+2].$binary[$s+3];

                $num=base_convert($bins,2,10);

                if ($num>9) {

                        die("the string is not a proper binary coded decimal\n");

                } else {

                        $res.=$num;

                }

        }

        return $res;

}

?>



a binary coded decimal is converted by taking groups of four from a decimal string,

for example the binary coded decimal string

1000 = 8

10001000 does not = 136 but 88

so

binarycodedstring2dec(1000) = 8

binarycodedstring2dec(11100000111001)=3839

binarycodedstring2dec(100000111001)=839



i truly have no idea if this function will be useful to anyone, i simply failed a physics midterm because i didn't know this so i wrote this function to make sure i would never forget how to convert binary coded decimals

down

cyrilbele at yahoo dot fr ¶

13 years ago


If you want to do sharding, at some point you will need to decide which shard to target. Here is a simple function to assign the data to a particular shard based on a key (usually identifier of the row)



Here is a simple function to get the shard based on the key and the number of shards available



<?php

function getShard($key,$nbShards) {

    $num = substr(base_convert(sha1($key), 16, 10),4,6);

    return $num%$nbShards;

}

?>

down

simon at simonster dot com ¶

18 years ago


Here are some functions for converting integers to and from base 256. Converting to base 64 is simple given these.



<?php

function to_base256($number, $from_base = 10) {

    $binary_number = base_convert($number, $from_base, 2);

    $final_string = "";

    $new_length = (ceil(strlen($binary_number)/8)*8);

    $binary_number = str_pad($binary_number, $new_length, "0", STR_PAD_LEFT);

    for($i=($new_length-8); $i>=0; $i-=8) {

        $final_string = chr(base_convert(substr($binary_number, $i, 8), 2, 10)).$final_string;

    }

    return $final_string;

}



function from_base256($string, $to_base = 10) {

    $number = "";

    for($i=0; $i<strlen($string); $i++) {

        $number .= str_pad(base_convert(ord($string{$i}), 10, 2), 8, "0", STR_PAD_LEFT);

    }

    return base_convert($number, 2, $to_base);

}

?>



Yes, I know that this would be more efficient if it used mod instead of base_convert, but it needs to work with integers > 32 bits.

down

fiftytoo at buckeyeexpress dot com ¶

18 years ago


I needed a function to invert a hex value, which i used for setting font colors when they were on a colored background, that way i will get a contrasting color.

Im sure there are other reasons to use this, you decide!!

<?php
function InvertColor($hex) {
  return sprintf("%06s",base_convert(($hex ^ 0xFFFFFF),10,16));
  };

print '<td bgcolor="BB2222"><font color="'.InvertColor(0xBB2222).'">Blah</font></td>';
// Prints 44dddd as the font color, which is it's opposite on the color wheel

?>

down

bpds ¶

10 years ago


A simple function to convert an int to any base.



<?php

function intToAlphaBaseN($n,$baseArray) {

    $l=count($baseArray);

    $s = '';

    for ($i = 1; $n >= 0 && $i < 10; $i++) {

        $s =  $baseArray[($n % pow($l, $i) / pow($l, $i - 1))].$s;

        $n -= pow($l, $i);

    }

    return $s;

}



$alpha=array('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z');

$r=rand(0, 99999999999);

echo(intToAlphaBaseN($r,$alpha));

?>

down

CJ Dennis ¶

16 years ago


Really huge numbers might be truncated at both ends.
eg:
<?php
$binary="11010101001111010001110101000100011110010110110".
"001111000010001010001111001100011010110110010010011010".
"001011010000001001011111110001010101101101011010101010".
"000100011101110010110010100111110001010010111010110011".
"001111111100011001011011001110001111110000101011010010";
print(strtoupper(base_convert($binary, 2, 16)));
?>
will output:
9E8EA23CB63C0000000000000000000000000000000000000000000000000000 (64 hex digits)
when the correct result would be:
6A9E8EA23CB63C228F31AD9268B4097F156D6AA11DCB29F14BACCFF196CE3F0AD2 (66 hex digits)
Notice that as well as the result showing '0's after B63C which you would expect it is also missing the first 6A before 9E.

down

xdv43 at yandex dot ru ¶

1 month ago


Convert Large Integer to Hexadecimal without PHP Math extension.

<?php
/* 
 * Created by Michael Renner  17-May-2006 03:24
*/
function baseConvert($numstring, $frombase, $tobase)
{
 
    $chars = "0123456789abcdefghijklmnopqrstuvwxyz";
    $tostring = substr($chars, 0, $tobase);
 
    $length = strlen($numstring);
    $result = '';
    for ($i = 0; $i < $length; $i++)
    {
        $number[$i] = strpos($chars, $numstring[$i]);
    }
    do
    {
        $divide = 0;
        $newlen = 0;
        for ($i = 0; $i < $length; $i++)
        {
            $divide = $divide * $frombase + $number[$i];
            if ($divide >= $tobase)
            {
                $number[$newlen++] = (int)($divide / $tobase);
                $divide = $divide % $tobase;
            } elseif ($newlen > 0)
            {
                $number[$newlen++] = 0;
            }
        }
        $length = $newlen;
        $result = $tostring[$divide] . $result;
    } while ($newlen != 0);
    return $result;
}

down

ardavies at tiscali dot co dot uk ¶

8 years ago


In order to convert base 26 (hexavigesimal) of just alphanumeric characters (A-Z), wthout integers, (as descibed at http://en.wikipedia.org/wiki/Hexavigesimal), I found this to be useful:

function base_convert_alpha(  $str,  $from,  $to  )
{
    $r = range( 'A', 'Z' );
    $clean = str_replace( $r, array_keys($r), $str );
    return base_convert( $clean, $from, $to );
}

echo base_convert_alpha(  "BAC",  26,  10  );

//$clean = 102 which then returns 678

down

tika dot pahadi at selu dot edu ¶

6 years ago


Note that the method can only convert max 1024 long numbers. Most people don't nee that but once I ran into an issue where binary string was converted into alphanumeric. In such case, you need to split them, convert them and join.

down

wadelau at gmail dot com ¶

4 years ago


Base62x gives an alternative way for traditional Base62 and/or Base64.

base62x_encode / base62x_decode would be merged into PHP as an extra module in the future.

Prior to that, users can download the PHP extra module via: https://github.com/wadelau/Base62x

down

denik dot od at gmail dot com ¶

9 years ago


Convert any length bits to HEX:

function bits2hex($bin)
{
   $out = "";
   for($i=0;$i<strlen($bin);$i+=8)
   {
      $byte = substr($bin,$i,8); if( strlen($byte)<8 ) $byte .= str_repeat('0',8-strlen($byte));
      $out .= base_convert($byte,2,16);
   }
   return $out;
}

VARNING! If the last byte is incomplete, it is supplemented with zeros as string!

down

-2

ohcc at 163 dot com ¶

5 years ago


<?php
    $v = base_convert(3.14, 10, 10);
    var_dump($v);
?>

output: string(3) "314"

down

bryan at bryanruiz dot com ¶

11 years ago


A RFC 4648 Compliant Base32 encode.  Send me an email if you end up making this thing more efficient with bitwise operations and whatever else.

<?php

/**
 * Encode in Base32 based on RFC 4648.
 * Requires 20% more space than base64  
 * Great for case-insensitive filesystems like Windows and URL's  (except for = char which can be excluded using the pad option for urls)
 *
 * @package default
 * @author Bryan Ruiz
 **/
class Base32 {

   private static $map = array(
        'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', //  7
        'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', // 15
        'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', // 23
        'Y', 'Z', '2', '3', '4', '5', '6', '7', // 31
        '='  // padding char
    );
    
   private static $flippedMap = array(
        'A'=>'0', 'B'=>'1', 'C'=>'2', 'D'=>'3', 'E'=>'4', 'F'=>'5', 'G'=>'6', 'H'=>'7',
        'I'=>'8', 'J'=>'9', 'K'=>'10', 'L'=>'11', 'M'=>'12', 'N'=>'13', 'O'=>'14', 'P'=>'15',
        'Q'=>'16', 'R'=>'17', 'S'=>'18', 'T'=>'19', 'U'=>'20', 'V'=>'21', 'W'=>'22', 'X'=>'23',
        'Y'=>'24', 'Z'=>'25', '2'=>'26', '3'=>'27', '4'=>'28', '5'=>'29', '6'=>'30', '7'=>'31'
    );
    
    /**
     *    Use padding false when encoding for urls
     *
     * @return base32 encoded string
     * @author Bryan Ruiz
     **/
    public static function encode($input, $padding = true) {
        if(empty($input)) return "";
        $input = str_split($input);
        $binaryString = "";
        for($i = 0; $i < count($input); $i++) {
            $binaryString .= str_pad(base_convert(ord($input[$i]), 10, 2), 8, '0', STR_PAD_LEFT);
        }
        $fiveBitBinaryArray = str_split($binaryString, 5);
        $base32 = "";
        $i=0;
        while($i < count($fiveBitBinaryArray)) {    
            $base32 .= self::$map[base_convert(str_pad($fiveBitBinaryArray[$i], 5,'0'), 2, 10)];
            $i++;
        }
        if($padding && ($x = strlen($binaryString) % 40) != 0) {
            if($x == 8) $base32 .= str_repeat(self::$map[32], 6);
            else if($x == 16) $base32 .= str_repeat(self::$map[32], 4);
            else if($x == 24) $base32 .= str_repeat(self::$map[32], 3);
            else if($x == 32) $base32 .= self::$map[32];
        }
        return $base32;
    }
    
    public static function decode($input) {
        if(empty($input)) return;
        $paddingCharCount = substr_count($input, self::$map[32]);
        $allowedValues = array(6,4,3,1,0);
        if(!in_array($paddingCharCount, $allowedValues)) return false;
        for($i=0; $i<4; $i++){ 
            if($paddingCharCount == $allowedValues[$i] && 
                substr($input, -($allowedValues[$i])) != str_repeat(self::$map[32], $allowedValues[$i])) return false;
        }
        $input = str_replace('=','', $input);
        $input = str_split($input);
        $binaryString = "";
        for($i=0; $i < count($input); $i = $i+8) {
            $x = "";
            if(!in_array($input[$i], self::$map)) return false;
            for($j=0; $j < 8; $j++) {
                $x .= str_pad(base_convert(@self::$flippedMap[@$input[$i + $j]], 10, 2), 5, '0', STR_PAD_LEFT);
            }
            $eightBits = str_split($x, 8);
            for($z = 0; $z < count($eightBits); $z++) {
                $binaryString .= ( ($y = chr(base_convert($eightBits[$z], 2, 10))) || ord($y) == 48 ) ? $y:"";
            }
        }
        return $binaryString;
    }
}

down

-1

Anonymous ¶

4 years ago


some other mini implementation of base32 without error catching. just bring things from 5 to 8 and 8 to 5 bit. greetings. mho

<?
function base32_decode($d)
    {
    list($t, $b, $r) = array("ABCDEFGHIJKLMNOPQRSTUVWXYZ234567", "", "");

    foreach(str_split($d) as $c)
        $b = $b . sprintf("%05b", strpos($t, $c));

    foreach(str_split($b, 8) as $c)
        $r = $r . chr(bindec($c));

    return($r);
    }

function base32_encode($d)
    {
    list($t, $b, $r) = array("ABCDEFGHIJKLMNOPQRSTUVWXYZ234567", "", "");

    foreach(str_split($d) as $c)
        $b = $b . sprintf("%08b", ord($c));

    foreach(str_split($b, 5) as $c)
        $r = $r . $t[bindec($c)];

    return($r);
    }
?>

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-1

andrew at youritland dot co dot uk ¶

8 years ago


Example of using base_convert to generate random passwords

function random_password()
{
  $rvalue1 = mt_rand(100,999);
  $rvalue2 = time();
  $rvalue3 = mt_rand(1000,9999);
  $rvalue4 = mt_rand(1,9);
  $rvalue5 = mt_rand(101,109);
  //combine values
  $rvalues = intval(((($rvalue2.$rvalue3) + $rvalue1)*$rvalue4) / $rvalue5);
  
  //return value in base-35 (will contain chars from '0' to 'z')
  return base_convert($rvalues,10,35);
}

Change the range of rvalue5 to get more or less characters. This setting
will return 8 chars.

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-1

liams dot test dot acc at gmail dot com ¶

7 years ago


I wrote this as part of a college assignment to shorten urls. It works for any base and with any range of characters, eg. A-Za-z0-9 etc. Hope it helps someone.

<?php

        $base = range(0, 1);
        $number = 255;

        function translate($base, $number){

                $array = array();
                $n = count($base);
                $i = $number;

                while(true){

                /* by dividing $i % $n we can get the remainder after the number has
                 * been divided by the base. Subtracting the result from $i (number), and dividing
                 * by $n (base) we reassign the result to $i, thus moving on to the next smallest
                 * exponent, and around for another go of the loop. It continues doing this, churning
                 * out the remainders until $i <= 0 at which point it breaks. 
                 */
                        
                        if($i <= 0){

                                break;
                        }else{
                                $r = ($i % $n);

                              //reassign the value of $i
                                $i = ($i - $r) / $n;

                                $array[] = $base[$r];
                        }
                }
                $string = implode("", $array);
                return $string;
        } 

        $string = translate($base, $number);
        echo $string;
        
        // prints 11111111
?

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-3

francesco[at]paladinux.net ¶

12 years ago


base convert is limited on standard base invented.
In some case, if you want to invented some translate code (for authorizion code 4 example) , I hope is usefull this example of base_convert-AS from decimal in 65imal base for a speedCode.
Some more specifical: you can transform using a db
$speedCodeDEC            = $idAziendaMittente.$idAziendaDestinatario.$idDDT ;

//$speedCodeDEC = 3000;

//
$BASECODE = array();
$BASECODE['items'] = 65;
$BASECODE[1]='1';
$BASECODE[2]='2';
$BASECODE[3]='3';
$BASECODE[4]='4';
....
$BASECODE[10]='a';
$BASECODE[11]='b';
$BASECODE[12]='c';
...
$BASECODE[36]='A';
$BASECODE[37]='B';
$BASECODE[38]='C';
...
$BASECODE[61]='Z';
$BASECODE[62]='/';
$BASECODE[63]='-';
$BASECODE[64]='+';
//

//print_r ($BASECODE);TEST

function creaSpeedCode ( $speedCodeDEC,$partialCode="",$BASECODE){

    @$division      = $speedCodeDEC/$BASECODE['items'];
    @$resultINT   = floor($speedCodeDEC/$BASECODE['items']);
    @$remnant          = $speedCodeDEC%$BASECODE['items'];
    $partialCode  = $BASECODE[$remnant].$partialCode;
echo "
    <br>
    Inserito speedCodeDEC:$speedCodeDEC - partialCode:$partialCode<br>
    items            : ".$BASECODE['items']."<br>
    division          : $division    <br>
    resultINT        : $resultINT    <br>
    remnant            : $remnant        <br>
    partialCode        : $partialCode    <br>
";//TEST    
    if ($resultINT > 65)     $partialCode = creaSpeedCode($resultINT,$partialCode,$BASECODE);
    return $BASECODE[$resultINT].$partialCode;
}
echo $speedCodeDEC."<br>";
echo $risultato = creaSpeedCode ( $speedCodeDEC,"",$BASECODE);

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-4

Ray Paseur sometimes uses GMail ¶

15 years ago


[EDIT BY danbrown AT php DOT net: This function provides conversion of Arabic numerals (those used by most of the world, the standard 1,2,3,4,...) into Roman numerals (I,II,III,IV,...).  The original author failed to provide a description, but due to the usefulness of the function, it is being preserved from deletion, and a simple description added.]



<?php

function roman_numerals($input_arabic_numeral='') {



    if ($input_arabic_numeral == '') { $input_arabic_numeral = date("Y"); } // DEFAULT OUTPUT: THIS YEAR

    $arabic_numeral            = intval($input_arabic_numeral);

    $arabic_numeral_text    = "$arabic_numeral";

    $arabic_numeral_length    = strlen($arabic_numeral_text);



    if (!ereg('[0-9]', $arabic_numeral_text)) {

return false; }



    if ($arabic_numeral > 4999) {

return false; }



    if ($arabic_numeral < 1) {

return false; }



    if ($arabic_numeral_length > 4) {

return false; }



    $roman_numeral_units    = $roman_numeral_tens        = $roman_numeral_hundreds        = $roman_numeral_thousands        = array();

    $roman_numeral_units[0]    = $roman_numeral_tens[0]    = $roman_numeral_hundreds[0]    = $roman_numeral_thousands[0]    = ''; // NO ZEROS IN ROMAN NUMERALS



    $roman_numeral_units[1]='I';

    $roman_numeral_units[2]='II';

    $roman_numeral_units[3]='III';

    $roman_numeral_units[4]='IV';

    $roman_numeral_units[5]='V';

    $roman_numeral_units[6]='VI';

    $roman_numeral_units[7]='VII';

    $roman_numeral_units[8]='VIII';

    $roman_numeral_units[9]='IX';



    $roman_numeral_tens[1]='X';

    $roman_numeral_tens[2]='XX';

    $roman_numeral_tens[3]='XXX';

    $roman_numeral_tens[4]='XL';

    $roman_numeral_tens[5]='L';

    $roman_numeral_tens[6]='LX';

    $roman_numeral_tens[7]='LXX';

    $roman_numeral_tens[8]='LXXX';

    $roman_numeral_tens[9]='XC';



    $roman_numeral_hundreds[1]='C';

    $roman_numeral_hundreds[2]='CC';

    $roman_numeral_hundreds[3]='CCC';

    $roman_numeral_hundreds[4]='CD';

    $roman_numeral_hundreds[5]='D';

    $roman_numeral_hundreds[6]='DC';

    $roman_numeral_hundreds[7]='DCC';

    $roman_numeral_hundreds[8]='DCCC';

    $roman_numeral_hundreds[9]='CM';



    $roman_numeral_thousands[1]='M';

    $roman_numeral_thousands[2]='MM';

    $roman_numeral_thousands[3]='MMM';

    $roman_numeral_thousands[4]='MMMM';



    if ($arabic_numeral_length == 3) { $arabic_numeral_text = "0" . $arabic_numeral_text; }

    if ($arabic_numeral_length == 2) { $arabic_numeral_text = "00" . $arabic_numeral_text; }

    if ($arabic_numeral_length == 1) { $arabic_numeral_text = "000" . $arabic_numeral_text; }



    $anu = substr($arabic_numeral_text, 3, 1);

    $anx = substr($arabic_numeral_text, 2, 1);

    $anc = substr($arabic_numeral_text, 1, 1);

    $anm = substr($arabic_numeral_text, 0, 1);



    $roman_numeral_text = $roman_numeral_thousands[$anm] . $roman_numeral_hundreds[$anc] . $roman_numeral_tens[$anx] . $roman_numeral_units[$anu];

return ($roman_numeral_text);

}

?>

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-8

Baji dot Panchumarti at gmail dot com ¶

10 years ago


Extending base_convert to bases above 36, up to base 62.

<?php
function base_convert_x( $_number='', $_frBase=10, $_toBase=62 ) {

#   Today's Date - C74 - convert a string (+ve integer) from any arbitrary base to any arbitrary base, up to base 62, using  0-9,A-Z,a-z
#
#   Usage :   echo base_convert_x( 123456789012345, 10, 32 );

  $_10to62 =  array(
    '0'  => '0', '1'  => '1', '2'  => '2', '3'  => '3', '4'  => '4', '5'  => '5', '6'  => '6', '7'  => '7', '8'  => '8', '9'  => '9', '00' => '0', '01' => '1', '02' => '2', '03' => '3', '04' => '4', '05' => '5', '06' => '6', '07' => '7',
    '10' => 'A', '11' => 'B', '12' => 'C', '13' => 'D', '14' => 'E', '15' => 'F', '16' => 'G', '17' => 'H', '18' => 'I', '19' => 'J', '20' => 'K', '21' => 'L', '22' => 'M', '23' => 'N', '24' => 'O', '25' => 'P', '26' => 'Q', '27' => 'R',
    '30' => 'U', '31' => 'V', '32' => 'W', '33' => 'X', '34' => 'Y', '35' => 'Z', '36' => 'a', '37' => 'b', '38' => 'c', '39' => 'd', '40' => 'e', '41' => 'f', '42' => 'g', '43' => 'h', '44' => 'i', '45' => 'j', '46' => 'k', '47' => 'l',
    '50' => 'o', '51' => 'p', '52' => 'q', '53' => 'r', '54' => 's', '55' => 't', '56' => 'u', '57' => 'v', '58' => 'w', '59' => 'x', '60' => 'y', '61' => 'z'  );

  $_62to10 =  array(
    '0' => '00', '1' => '01', '2' => '02', '3' => '03', '4' => '04', '5' => '05', '6' => '06', '7' => '07', '8' => '08', '9' => '09', 'A' => '10', 'B' => '11', 'C' => '12', 'D' => '13', 'E' => '14', 'F' => '15', 'G' => '16', 'H' => '17',
    'K' => '20', 'L' => '21', 'M' => '22', 'N' => '23', 'O' => '24', 'P' => '25', 'Q' => '26', 'R' => '27', 'S' => '28', 'T' => '29', 'U' => '30', 'V' => '31', 'W' => '32', 'X' => '33', 'Y' => '34', 'Z' => '35', 'a' => '36', 'b' => '37',
    'e' => '40', 'f' => '41', 'g' => '42', 'h' => '43', 'i' => '44', 'j' => '45', 'k' => '46', 'l' => '47', 'm' => '48', 'n' => '49', 'o' => '50', 'p' => '51', 'q' => '52', 'r' => '53', 's' => '54', 't' => '55', 'u' => '56', 'v' => '57',
    'y' => '60', 'z' => '61' );

#   ---- First convert from frBase to base-10

    $_in_b10        =   0;
    $_pwr_of_frB    =   1;                        #  power of from base, eg. 1, 8, 64, 512
    $_chars         =   str_split( $_number );    #  split input # into chars
    $_str_len       =   strlen( $_number );
    $_pos           =   0;

    while     (  $_pos++ < $_str_len )  {
        $_char          =   $_chars[$_str_len - $_pos];
        $_in_b10       +=   (((int) $_62to10[$_char] ) * $_pwr_of_frB);
        $_pwr_of_frB   *=   $_frBase;
    }

#   ---- Now convert from base-10 to toBase

    $_dividend      =   (int)   $_in_b10;         #  name dividend easier to follow below
    $_in_toB        =   '';                       #  number string in toBase

    while     ( $_dividend > 0 )        {

        $_quotient  =   (int) ( $_dividend / $_toBase );    #  eg. 789 / 62  =  12  ( C in base 62 )
        $_remainder =   ''  .  ( $_dividend % $_toBase );   #  789 % 62  =  45  ( j in base 62 )
        $_in_toB    =   $_10to62[$_remainder] . $_in_toB;   #  789  (in base 10)  =    Cj  (in base 62)
        $_dividend  =   $_quotient;                         #  new dividend is the quotient from base division
    }

    if  ( $_in_toB  ==  '' )
          $_in_toB  =   '0';

    return    $_in_toB;                           #  base $_toBase string
}
#   --------- examples -------
    echo base_convert_x( '3456789ABCDEF', 16, 10 ) . "\n";    #  920735923817967
    echo   base_convert( '3456789ABCDEF', 16, 10 ) . "\n";    #  920735923817967
?>

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