array_rand() is rather useful when you want to
pick one or more random entries out of an array. It takes an
input
array and an optional argument
num_req
which specifies how many entries you
want to pick - if not specified, it defaults to 1.
If you are picking only one entry, array_rand() returns the key for a random entry. Otherwise, it returns an array of keys for the random entries. This is done so that you can pick random keys as well as values out of the array.
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.
See also shuffle().