PHP 5.6.0RC3 is available

gmp_strval

(PHP 4 >= 4.0.4, PHP 5)

gmp_strvalConvierte un número GMP a cadena

Descripción

string gmp_strval ( resource $gmpnumber [, int $base = 10 ] )

Convierte un número GMP a la representación de cadena en base base. La base por defecto es 10.

Parámetros

gmpnumber

El número GMP a convertir en cadena.

resource de número de GMP en PHP 5.5 y anterior, o un objeto de GMP en PHP 5.6 y posterior, o un string numérico siempre que sea posible convertirlo a un número.

base

La base del número retornado. La base por defecto es 10. Los valores permitidos para la base son de 2 a 62 y -2 a -36.

Valores devueltos

El número, como una string.

Historial de cambios

Versión Descripción
5.3.2 La base fue extendida de 2 a 36, a 2 a 62 y -2 a -36.

Notas

Nota:

To use the extended base introduced in PHP 5.3.2, then PHP must be compiled against GMP 4.2.0 or greater.

Ejemplos

Ejemplo #1 Converting a GMP number to a string

<?php
$a 
gmp_init("0x41682179fbf5");
printf("Decimal: %s, base 36: %s"gmp_strval($a), gmp_strval($a,36));
?>

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User Contributed Notes 3 notes

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0
russell dot s dot harper at gmail dot com
4 years ago
A gotcha when using the value from gmp_strval as a key in an associative array. Some numbers are 2^31 are converted to signed integer format, this is usually incorrect.

<?php

$a
= gmp_init('2147483649'); // = 2^31 + 1
$b = gmp_init('3173604585'); // = 2^31 < $b < 2^32

$c = gmp_strval($a);
$d = gmp_strval($b);

$e = array($c => 'c', $d => 'd');

print
'*** Expect '."\n";
print
'Array '."\n".'('."\n".'    ['.$c.'] => c'."\n".'    ['.$d.'] => d'."\n".')'."\n\n";
print
'*** Actual '."\n";
print_r($e);

?>

Output:

*** Expect
Array
(
    [2147483649] => c
    [3173604585] => d
)

*** Actual
Array
(
    [-2147483647] => c
    [3173604585] => d
)

A workaround is to format as base 16 and append '0x' before using as a key.
up
0
php at richardneill dot org
7 years ago
I think it's no longer necessary to worry about trailing nulls. This was fixed in Feb 2002 (see bug 10133)
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0
caldwell at utm dot NoSpamPlease dot edu
13 years ago
Warning: gmp_strval may return a null terminated string (e.g., gmp_strval(gmp_init(8)) has two characters. This is because gmp is built for speed, so uses estimates based on things it can get quickly, like the number of bits in N. So since 8 is a 4 bit number, it will be allocated ceil(log10(2^4))=ceil(4*0.30103....) = 2 characters. The gmp folks feel it is the caller's responsibility (in this case the PHP interface) to check whether or not all the characters were required.  PHP might have done this for us (and may in the future), but for now, you need to check (if it matters to you--it sure did in my program!).
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