5 star rating - calculation help

[Speedy84]

I want to set up a 5 star rating system on my site. But I need some help with the calculations.. all I can come up with at this point is create a column in the db called "points" and one called "totaltvotes" and then do something like "points/totalvotes".. but i'm positive that this is wrong =)

[Mchl]

Why you're so positive about it being wrong? It will give you an average for given item. Is it not what you want?

[bobbinsbro]

what you probably want to find the weighted average. something like this:

 

(1*(total 1 start votes) + 2*(total 2 star votes) + ... + 5*(total 5 star votes))/(total votes)

 

if you want a round number, use the round() function.

[Mchl]

That's same as having one star being worth one point, and five stars being worth five points... Why overcomplicate?

[Speedy84]

hm... well i might try, but what should i do?

 

something like this?

$points = 5;
$totalvotes = 1;
$rating = $points / $totalvotes;
if (($rating >= 1) && ($rating <= 49)) { show_one_star; }
elseif (($rating >= 50) && ($rating <= 99)) { show_two_stars; }

[Andy-H]

http://gr0w.com/articles/code/php_5_star_rating_system_using_hreview/

[Mchl]

No.

 

$starsToShow = round($points/$totalvotes);

[laffin]

Careful with that, ya might get a divide by zero

$rating = round(($points && $totalvotes)?($points / $totalvotes):0);

 

is all u need, cuz ya only have 1 - 5 as a scale

so dividing the total points by total votes will still give u a range of 1 - 5

using the round function well makes shure yer at a whole number

 

switch($ratiing)
{
  case 1:
      // 1 star
      break;
.
.
  default:
      // no stars
}

 

or use if/ifelse/else structure