PHP Conference Nagoya 2025

Random\Randomizer::getBytesFromString

(PHP 8 >= 8.3.0)

Random\Randomizer::getBytesFromStringGet random bytes from a source string

Descripción

public Random\Randomizer::getBytesFromString(string $string, int $length): string

Generates a string containing uniformly selected random bytes from the input string with the requested length.

The chance for a byte to be selected is proportional to its share of the input string. If each byte occurs the same amount of times, each byte is equally likely to be selected.

Parámetros

string

The string from which the returned bytes are selected.

length

The length of the random string that should be returned in bytes; must be 1 or greater.

Valores devueltos

A string containing the requested number of random bytes taken from the input string.

Errores/Excepciones

Ejemplos

Ejemplo #1 Random\Randomizer::getBytesFromString() example

<?php
$randomizer
= new \Random\Randomizer();

printf(
"%s.example.com",
$randomizer->getBytesFromString('abcdefghijklmnopqrstuvwxyz0123456789', 16)
);
?>

El resultado del ejemplo sería algo similar a:

3zsw04eiubcf82jd.example.com

Ejemplo #2 Generate a random code for multi-factor authentication

<?php
// The Secure engine is the default, but we make it explicit, because
// multi-factor codes are security sensitive.
$randomizer = new \Random\Randomizer(new \Random\Engine\Secure());

echo
implode('-', str_split($randomizer->getBytesFromString('0123456789', 20), 5));
?>

El resultado del ejemplo sería algo similar a:

11551-80418-27047-42075

Ejemplo #3 Select from a string with a non-uniform distribution

<?php
$randomizer
= new \Random\Randomizer();

echo
$randomizer->getBytesFromString('aaaaabcdef', 20);
?>

El resultado del ejemplo sería algo similar a:

fddacbeaaeaaacaaaaca

Ver también

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