rand

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

randGenerate 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().

Nota: On some platforms (such as Windows), getrandmax() is only 32767. 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:

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Note

Avviso

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

Vedere anche:

  • srand() - Seed the random number generator
  • getrandmax() - Show largest possible random value
  • mt_rand() - Generate a random value via the Mersenne Twister Random Number Generator
  • random_int() - Get a cryptographically secure, uniformly selected integer
  • random_bytes() - Get cryptographically secure random bytes

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