(PHP 4, PHP 5, PHP 7, PHP 8)
base_convert —Convert a number between arbitrary bases
Returns a string containingnum represented in baseto_base. The base in whichnum is given is specified infrom_base. Bothfrom_base andto_base have to be between 2 and 36, inclusive. Digits in numbers with a base higher than 10 will be represented with the letters a-z, with a meaning 10, b meaning 11 and z meaning 35. The case of the letters doesn't matter, i.e.num is interpreted case-insensitively.
base_convert() may lose precision on large numbers due to properties related to the internalfloat type used. Please see theFloating point numbers section in the manual for more specific information and limitations.
num The number to convert. Any invalid characters innum are silently ignored. As of PHP 7.4.0 supplying any invalid characters is deprecated.
from_base The basenum is in
to_base The base to convertnum to
num converted to baseto_base
| Version | Description |
|---|---|
| 7.4.0 | Passing invalid characters will now generate a deprecation notice. The result will still be computed as if the invalid characters did not exist. |
Example #1base_convert() example
<?php
$hexadecimal='a37334';
echobase_convert($hexadecimal,16,2);
?>The above example will output:
101000110111001100110100
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 '~!@#$%^&*()' as the numbers.
//result: !%~!!*&!~^!!&(&!~^@#@@@&
functionconvBase($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;
}
?>In order to convert base 26 (hexavigesimal) of just alphanumeric characters (A-Z), wthout integers, (as descibed athttp://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 678While not immediately clear from the description above, a negative sign is also "silently ignored".
base_convert("-12", 10, 10) => 12If 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*/
functiongmp_convert($num,$base_a,$base_b)
{
returngmp_strval(gmp_init($num,$base_a),$base_b);
}
?><?php
$v=base_convert(3.14,10,10);
var_dump($v);
?>
output: string(3) "314"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
functiongetShard($key,$nbShards) {
$num=substr(base_convert(sha1($key),16,10),4,6);
return$num%$nbShards;
}
?>