mt_rand

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

mt_randGenerate a random value via the Mersenne Twister Random Number Generator

Descrição

mt_rand(): int
mt_rand(int $min, int $max): int

Many random number generators of older libcs have dubious or unknown characteristics and are slow. The mt_rand() function is a drop-in replacement for the older rand(). It uses a random number generator with known characteristics using the » Mersenne Twister, which will produce random numbers four times faster than what the average libc rand() provides.

If called without the optional min, max arguments mt_rand() returns a pseudo-random value between 0 and mt_getrandmax(). If you want a random number between 5 and 15 (inclusive), for example, use mt_rand(5, 15).

Cuidado

Esta função não gera valores criptograficamente seguros e não deve ser usada para propósitos criptográficos ou fins que exijam que os valores retornados sejam impossíveis de adivinhar.

Se aleatoriedade criptograficamente segura for necessária, a classe Random\Randomizer pode ser usada com o mecanismo Random\Engine\Secure. Para casos de uso simples, as funções random_int() e random_bytes() fornecem uma API conveniente e segura que é garantida pelo CSPRNG do sistema operacional.

Parâmetros

min

Optional lowest value to be returned (default: 0)

max

Optional highest value to be returned (default: mt_getrandmax())

Valor Retornado

A random integer value between min (or 0) and max (or mt_getrandmax(), inclusive), or false if max is less than min.

Registro de Alterações

Versão Descrição
7.2.0 mt_rand() has received a bug fix for a modulo bias bug. This means that sequences generated with a specific seed may differ from PHP 7.1 on 64-bit machines.
7.1.0 rand() has been made an alias of mt_rand().
7.1.0 mt_rand() has been updated to use the fixed, correct, version of the Mersenne Twister algorithm. To fall back to the old behaviour, use mt_srand() with MT_RAND_PHP as the second parameter.

Exemplos

Exemplo #1 mt_rand() example

<?php
echo mt_rand(), "\n";
echo
mt_rand(), "\n";

echo
mt_rand(5, 15), "\n";
?>

O exemplo acima produzirá algo semelhante a:

1604716014
1478613278
6

Notas

Aviso

min max range must be within the range mt_getrandmax(). i.e. (max - min) <= mt_getrandmax() Otherwise, mt_rand() may return poorer random numbers than it should.

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