Random\Randomizer::getBytesFromString
(PHP 8 >= 8.3.0)
Random\Randomizer::getBytesFromString — Get random bytes from a source string
Description
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.
Parameters
Return Values
A string containing the requested number of random bytes taken from the input string.
Errors/Exceptions
-
If
stringis empty, a ValueError will be thrown. -
If the value of
lengthis less than1, a ValueError will be thrown. -
Any Throwables thrown by the Random\Engine::generate() method
of the underlying
Random\Randomizer::$engine.
Examples
Example #1 Random\Randomizer::getBytesFromString() example
<?php
$randomizer = new \Random\Randomizer();
printf(
"%s.example.com",
$randomizer->getBytesFromString('abcdefghijklmnopqrstuvwxyz0123456789', 16)
);
?>The above example will output something similar to:
3zsw04eiubcf82jd.example.com
Example #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));
?>The above example will output something similar to:
11551-80418-27047-42075
Example #3 Select from a string with a non-uniform distribution
<?php
$randomizer = new \Random\Randomizer();
echo $randomizer->getBytesFromString('aaaaabcdef', 20);
?>The above example will output something similar to:
fddacbeaaeaaacaaaaca
See Also
- Random\Randomizer::getBytes() - Get random bytes
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