multiple random numbers

themanwhowas

hi guys.

i can use mt_rand() to generate a random number, but if i wanted to generate say, 5 random numbers between 1 and 20, how would i do this?
no 2 numbers can be the same so i cant just use mt_rand() 5 times.
i have searched with google and searched php.net but i cant see any way of doing this.

any help is greatly appreciated.

thanks

oops. I can do this in mysql with select_rand(number) from table limit 5; but i would prefer a non sql way if possible

NogDog

$numbers = range(1,20);
shuffle($numbers);
$fiveRandomNumbers = array_slice($numbers, 0, 5);
print_r($fiveRandomNumbers);

themanwhowas

you're the best nogdog.

and at the risk of highlighting my mistake, in mysql it would have been
select number from table order by rand() limit 5;

bradgrafelman

themanwhowas wrote:
and at the risk of highlighting my mistake

You're right - you definitely highlighted a mistake there.

You should never use 'ORDER BY RAND()' in MySQL. Sure, you can get away with it in small tables, but why even get into this terrible coding habit? For more information on why it is bad to use this method to get random results, check out this stickied thread in the Database forum.

themanwhowas

you learn something everyday

Weedpacket

You could also use [man]array_rand[/man] to get a random sample from an array. Keep in mind that it returns keys, not values, so array_rand(range(1,20), 5) would actually return five random integers in the range [0..19].