getting null value on var_dump(getRecommendation($matrix,$getName)); - php

Question

I am getting null value for function getRecommendation($matrix,$getName), the data obtained are working fine
still learining php
<?php
require('connection.inc.php');
require('recommend.php');
$userID=$_SESSION['USER_ID'];
$reco=mysqli_query($con,"select userrating.*,product.id,product.productName from userrating,product where userrating.userID='$userID' and product.id=userrating.productID");
$matrix=array();
while($rec=mysqli_fetch_array($reco))
{
$users=mysqli_query($con,"select users.name from users where users.id=$rec[userID]");
$username=mysqli_fetch_array($users);
$matrix[$username['name']][$rec['productName']]=$rec['rating'];
$getName= $username['name'];
}
var_dump(getRecommendation($matrix,$getName));
?>
Here is the function code as well, it is for a recommendor system , fur now i jst need this code not to return null value
$value)
{
if(array_key_exists($key,$matrix[$product2]))
{
$similar[$key]=1;
}
}
if($similar==0)
{
return 0;
}
foreach($matrix[$product1] as $key=>$value)
{
if(array_key_exists($key,$matrix[$product2]))
{
$sum=$sum+pow($value - $matrix[$product2][$key],2);
}
}
return 1/(1+sqrt($sum));
}
function getRecommendation($matrix,$prod)
{
foreach($matrix as $otherProduct=>$value)
{
if($otherProduct!=$prod){
$sim=similarityDistance($matrix,$prod,$otherProduct);
var_dump($sim);
}
}
}
?>

Answer 1

You have to actually return something from the function getRecommendation. (That's why you get NULL now. The functions isn't returning anything).
function getRecommendation($matrix,$prod)
{
foreach($matrix as $otherProduct=>$value)
{
if($otherProduct!=$prod){
$sim=similarityDistance($matrix,$prod,$otherProduct);
var_dump($sim);
}
}
//I don't what you want to return. Maybe this, but it has to be something..
return $sim;
}