An elegant way to return random float between two numbers:
<?php
function random_float ($min,$max) {
return ($min+lcg_value()*(abs($max-$min)));
}
?>
lcg_value
(PHP 4, PHP 5, PHP 7, PHP 8)
lcg_value — Combined linear congruential generator
Descrizione
lcg_value(): float
lcg_value() returns a pseudo random number in the range of (0, 1). The function combines two CGs with periods of 2^31 - 85 and 2^31 - 249. The period of this function is equal to the product of both primes.
Attenzione
Questa funzione non genera valori crittograficamente sicuri, e non dovrebbe essere usata per scopi di crittografia. Se c'è necessità di utilizzare un valore crittograficamente sicuro, si preferisca openssl_random_pseudo_bytes().
Attenzione
Scaling the return value to a different interval using multiplication or addition (a so-called affine transformation) might result in a bias in the resulting value as floats are not equally dense across the number line. As not all values can be exactly represented by a float, the result of the affine transformation might also result in values outside of the requested interval.
Use Random\Randomizer::getFloat() to generate a random float within an arbitrary interval. Use Random\Randomizer::getInt() to generate a random integer within an arbitrary interval.
Elenco dei parametri
Questa funzione non contiene parametri.
Valori restituiti
A pseudo random float value between 0.0 and 1.0, inclusive.
Vedere anche:
- Random\Randomizer::getFloat() - Get a uniformly selected float
- Random\Randomizer::getInt() - Get a uniformly selected integer
- random_int() - Get a cryptographically secure, uniformly selected integer
add a note
User Contributed Notes 3 notes
rok kralj gmail com ¶
17 years ago
daniel dot baulig at gmx dot de ¶
14 years ago
Choose your weapon:
<?php
function mt_randf($min, $max)
{
return $min + abs($max - $min) * mt_rand(0, mt_getrandmax())/mt_getrandmax();
}
function lcg_randf($min, $max)
{
return $min + lcg_value() * abs($max - $min);
}
function randf($min, $max)
{
return $min + rand(0,getrandmax()) / getrandmax() * abs($max - $min);
}?>
