php - How do I calculate the average rating of the detail rating? -

my code :

<?php      $rating = 5;     $rating_detail = '{"3":"1","4":"2"}';     $array_data = json_decode($rating_detail, true);     if(array_key_exists($rating, $array_data)) {         $value = $array_data[$rating];         if ($value !== false) {             $array_data[$rating] = (string)((int)$value + 1);         }         $rating_detail = json_encode($array_data);     }     else {         $data = substr($rating_detail, 0, -1);         $rating_detail = $data.',"'.$rating.'":"1"}';     }      echo '<pre>';print_r($rating_detail);echo '</pre>';die(); ?> 

if code run, result :

{"3":"1","4":"2","5":"1"}

it's detail rating of store

note :

3 = rating 3, 1 = number of users giving ratings : 1

4 = rating 4, 2 = number of users giving ratings : 2

5 = rating 5, 1 = number of users giving ratings : 1

how calculate average rating of detail rating?

so average rating of detail rating of store between 1 - 5

update

so here :

{"3":"1","4":"2","5":"1"}

based on detail of rating, how calculate rating of store?

try this

$rating = 5; $rating_detail = '{"3":"1","4":"2"}'; $rating_detail = json_decode($rating_detail, true); if(array_key_exists($rating, $rating_detail)) {         $rating_detail[$rating] = (string)((int)$rating_detail[$rating] + 1); } else {     $rating_detail[$rating]="1"; } $totalstar=$totalrate=0; foreach ($rating_detail $key=>$value){     $totalstar+=$key*$value;     $totalrate+=$value;  } $average=$totalstar/$totalrate; 

it give out put as