A math question?

alanzhao

Hi,

here is my idea, when a user click on a link to page 'get_prize.php' he has 10% of chance to get a bucket of gold or go home(90%). How do I get the result? Do I need another variable?

$chance = 0.1;
$prize = 'A bucket of Gold';
$no_prize = 'Go Home';

$result = '';

It's a stupid qestion...

NogDog

$percent = 10;
$result = (rand(1, 100) <= $percent) ? 'A buckent of Gold' : 'Go Home' ;

alanzhao

Thanks again!

I like this forum, it's like I have a personal tutor that can get every question answered.

Thanks!

TheDefender

For the Ternary Operator impaired, here's the same thing NogDog is doing using normal if/else syntax, rather than the ternary.

$percent = 10; 
if(rand(1, 100) <= $percent) {
    $prize_result = "A bucket of Gold!";
} else {
    $prize_result = "Go Home!";
}

echo $prize_result;

The syntax is a bit longer, but it's worth it, rather than trying to decipher what's going on in Ternary coding, since it's a small portion of coders who really know what it is, or how to properly use it... (No offense NogDog, if that's your coding style... I prefer not to use the ternary when helping others, and in fact, I tend to not recommend its usage by anyone).

alanzhao


<?php

$percent = 10;

$prize = 'A bucket of Gold';
$no_prize = 'Go Home';

$winners = 0;
$users = 1000;

for ($i = 1; $i <= $users; $i++) {
	$result = (rand(1, 100) <= $percent) ? $prize : $no_prize;
	if ($result == $prize) $winners++;
	//echo $result;
	//echo "<br>";
}

echo "Number of winners out of " . $users . " users: " . $winners;
?>

ok, it tried the above code and produced around 80 to 120 winners out of 1000 users(exact 10% of users). Is there a way to produce exactly 100 out of 1000 assuming the user amount is unknown?

Weedpacket

Well, if the user amount is unknown then you don't know if it's 1000; so I'm guessing you really do want exactly 10% of whatever the number of users is. I also figure you want to round that off in some way or another, if it's not a whole number 😉

$winners = array_rand(range(1,$users), round($users/10));

That's an array containing 10% of the numbers between 1 and $users inclusive.