(PHP 3 >= 3.0.6, PHP 4, PHP 5)
mt_rand -- Generate a better random value
Description
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
RAND_MAX. If you want a random number
between 5 and 15 (inclusive), for example, use mt_rand
(5, 15).
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: |
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.
Note:
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 mt_rand (5, 11) to get a random number
between 5 and 15.
See also:
mt_srand(),
mt_getrandmax(), and
rand().
mt_getrandmax
