Random number question

jebster

I have a script that picks 6 random number, but sometimes it picks the same one twice or three times etc. How can I pervent this?

$Number1 = rand(1,49) ;
$Number2 = rand(1,49) ;
$Number3 = rand(1,49) ;
$Number4 = rand(1,49) ;
$Number5 = rand(1,49) ;
$Number6 = rand(1,49) ;

How would I modify that so if $number1 picks a number no of the others pick it and same for the rest? Thanks

tomhath

Did you call srand() first?

http://www.phpbuilder.com/manual/function.rand.php

To eliminate duplicates, you'll just have to check if the number was already selected and keep calling rand() in a loop until you get a non-duplicate.

bike5

after first randoms

$done = 0;

while ($done = 0){

if ($Number2==$Number1){
$Number2 = rand(1,49) ;
}
if ($Number3==$Number2 || $Number3==$Number1){
$Number3 = rand(1,49) ;
}
\keep on that pattern till the last number, then test at the end of the loop that none are == any other one and if its true set $done to = 1

}

I know theres probably a better way to do that but im in my java class and gota go right now! teacher starting to stare at me..lol

dalecosp

$MyArray=array_rand(rand(0,49), 6);

This would produce an array of 6 numbers, randomly chosen from within the range. They won't be duplicated.

You might also look at is_unique(), or is it unique_array()??? Ah, neither.... array_unique() !!!

HTH,

ednark

[man]rand/man is a poor random number generator, even when you use [man]srand/man

use [man]mt_rand/man instead (which comes with php) and you will be happier

cahva

Originally posted by tomhath
Did you call srand() first?

http://www.phpbuilder.com/manual/function.rand.php

Thats a little outdated manual in there.

From php.net manual:
"In older versions of PHP, you had to seed the random number generator before use with srand(). Since 4.2.0 this is no longer necessary."

But, yeah. mt_rand() is way to go...

jebster

Cool thanks all! 😃

Oh and dalecosp,

$MyArray=array_rand(rand(0,49), 6);

Gives me an error:
Warning: Argument to array_rand() has to be an array in C:\Inetpub\wwwroot\random.php on line 2

diego25

Instead of rand(0,49) use range(0,49)

Diego

dalecosp

Yes, diego, thank you; I'm sorry, Jebster, it was so late I mistyped the example....should have been range()

Please don't think me as much of an idiot as this example showed...my brain just went Pfft! as it oft does when the hour is late...

jebster

Works now, thanks! 🙂