Php/docs/function.rand

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rand

(PHP 4, PHP 5, PHP 7)

randGenerate a random integer


Description

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).

Caution This function does not generate cryptographically secure values, and should not be used for cryptographic purposes. If you need a cryptographically secure value, consider using random_int(), random_bytes(), or openssl_random_pseudo_bytes() instead.


Note:

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.

Note:

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().

Parameters

min
The lowest value to return (default: 0)
max
The highest value to return (default: getrandmax())


Return Values

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


Changelog

Version Description
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().


Examples

Example #1 rand() example

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

The above example will output something similar to:


7771
22264
11

Notes

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


See Also