Random\Randomizer::getBytesFromString

(PHP 8 >= 8.3.0)

Random\Randomizer::getBytesFromString — Get random bytes from a source string

说明

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.

参数

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.

返回值

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

错误／异常

示例

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

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

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

以上示例的输出类似于：

3zsw04eiubcf82jd.example.com

示例 #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));
?>

以上示例的输出类似于：

11551-80418-27047-42075

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

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

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

以上示例的输出类似于：

fddacbeaaeaaacaaaaca

参见