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rand

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

rand — Generate a random integer

Descrizione

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

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

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

This function uses the global Mt19937 (“Mersenne Twister”) instance as the source of randomness and thus shares its state with all other functions using the global Mt19937. Using any of these functions advances the sequence for all the other functions, regardless of scope.

Generating repeatable sequences by seeding mt_srand() or srand() with a known value will also yield repeatable output from this function.

Prefer using Random\Randomizer methods in all newly written code.

Nota: Prior to PHP 7.1.0, getrandmax() was only 32767 on some platforms (such as Windows). If you require a range larger than 32767, specifying min and max will allow you to create a range larger than this, or consider using mt_rand() instead.

Nota: As of PHP 7.1.0, rand() uses the same random number generator as mt_rand(). To preserve backwards compatibility rand() allows max to be smaller than min as opposed to returning false as mt_rand().

Elenco dei parametri

min

The lowest value to return (default: 0)

max

The highest value to return (default: getrandmax())

Valori restituiti

A pseudo random value between min (or 0) and max (or getrandmax(), inclusive).

Log delle modifiche

Versione Descrizione
7.2.0 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().

Esempi

Example #1 rand() example

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

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

Il precedente esempio visualizzerà qualcosa simile a:

7771
22264
11

Note

Avviso

min max range must be within the range getrandmax(). i.e. abs(max - min) <= getrandmax(). Otherwise, rand() may return poor-quality random numbers.

Vedere anche: