PHP: mt_rand function - Generate a better random value

Description

int mt_rand ( void )

int mt_rand ( int $min , int $max )

Many random number generators of older libcs have dubious or unknown characteristics and are slow. By default, PHP uses the libc random number generator with the rand() function. The mt_rand() function is a drop-in replacement for this. It uses a random number generator with known characteristics using the » Mersenne Twister, which will produce random numbers four times faster than what the average libc rand() provides.

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

Note: As of PHP 4.2.0, there is no need to seed the random number generator with srand() or mt_srand() as this is now done automatically.

Parameters

min: Optional lowest value to be returned (default: 0)
max: Optional highest value to be returned (default: mt_getrandmax())

Return Values

A random integer value between min (or 0) and max (or mt_getrandmax(), inclusive)

ChangeLog

Version	Description
Since 3.0.7	In versions before 3.0.7 the meaning of `max` was `range` . To get the same results in these versions the short example should be rand (5, 11) to get a random number between 5 and 15.

Examples

Example #1 mt_rand() example


<?php
echo mt_rand() . "\n";
echo mt_rand() . "\n";

echo mt_rand(5, 15);
?>

The above example will output something similar to:

1604716014
1478613278
6

mt_rand

Description

Parameters

Return Values

ChangeLog

Examples

See Also