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Answer 1

+4 A:

You can't directly make rand() do that, but you can do something like this:

<?PHP
function roll(){
   if(rand(0,1))  //this should evaluate true half the time.
       return 1;
   return rand(2,6); //the other half of the time we want this.
}

timdev 2009-10-12 23:18:56

You forgot to post your code!

Byron Whitlock 2009-10-12 23:22:01

When writing incremental answers you should at least try making the intermediate revisions helpful.

Joey 2009-10-12 23:22:01

Yeah, fat-fingered. Always end up hitting tab in the answer box, somehow followed it with a space or enter.

timdev 2009-10-12 23:24:18

Answer 2

+6 A:

You could do something like this

if (rand(0,1))
{
 $roll = rand(2,6);
}
else
{
 $roll = 1;
}

Byron Whitlock 2009-10-12 23:21:03

+1 for same answer as me, and being able to type without accidentally submitting forms.

timdev 2009-10-12 23:25:36

Answer 3

A:

A slightly different solution. It isn't as elegant, but perhaps more conducive to loading the die more finely?

$i = rand(1, 9);
if($i<=3)
{
    $num = 1;
}
else $num = $i-2;

Chinmay Kanchi 2009-10-12 23:29:11

Your code only gives 1 a third of the time, and it can also give 7.

Grandpa 2009-10-12 23:56:50

Serves me right for posting answers when I'm tired...

Chinmay Kanchi 2009-10-13 00:57:14

Answer 4

A:

So if you want to guarantee that in the last 6 rolls their would always have been at least 3 ones, I think you would have to track the history of the rolls. Here is a way to do that:

<?php

if (array_key_exists('roll_history', $_GET)) {
    $rollHistory = unserialize($_GET['roll_history']);
} else {
    $rollHistory = array();
}

$oneCount = 0;
foreach($rollHistory as $roll) {
    if ($roll == 1) {
     $oneCount++;
    }
}

if (6 - count($rollHistory) + $oneCount <= 3) {
    $roll = 1;
} else {
    if (rand(0,1)) {
        $roll = rand(2,6);
    } else {
        $roll = 1;
    }
}
$rollHistory[] = $roll;
if (count($rollHistory) > 5) {
    array_shift($rollHistory);
}

echo '<p>Weighted Dice Role: ' . $roll . '</p>';
echo '<form action="' . $_SERVER['PHP_SELF'] . '" method="get" >';
echo '<input type="hidden" name="roll_history" value="' . htmlspecialchars(serialize($rollHistory)) . '" />';
echo '<input type="submit" value="Roll Again" name="roll_again" />';
echo '</form>';

Brian Fisher 2009-10-12 23:45:20

Answer 5

A:

Rather than call rand() twice, you can simply do a little extra math.

$roll = $x = rand(1,12)-6 ? $x : 1;

Frank Farmer 2009-10-13 00:19:15

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