How to mutiply all values in a PHP foreach array [duplicate] - php

Question

This question already has answers here:
Multiply each integer in a flat array by 60
(5 answers)
Closed 9 years ago.
i want to mutiply all the values in a foreach array by itself
here is an example of the array
Array ( [0] => 2.4 [1] => 6 )
, all i want to do is mutiply 2.4*6
foreach($pp_events as $key=>$value)
{
#echo $value;
$pick=mysql_query("select * from pick where eventid='$value'");
$row=mysql_fetch_array($pick);
$sum*=$row['startPrice'];
}

Answer 1

There's no need to implement this yourself. PHP has a built-in function for multiplying all the values in an array - array_product(). Use that instead:
$products = array();
foreach ($pp_events as $key => $value) {
$pick = mysql_query("select * from pick where eventid='$value'");
$row = mysql_fetch_array($pick);
$products[] = $row['startPrice'];
}
echo array_product($products);
See also:
Why shouldn't I use mysql_* functions in PHP?

Answer 2

You need to initialize the variable to 1, then your loop should work.
$product = 1;
foreach ($pp_events as $key => $value) {
$pick = mysql_query("select * from pick where eventid='$value'");
$row = mysql_fetch_array($pick);
$product *= $row['startPrice'];
}
echo $product;
You can also do a single query, instead of a separate query for each value:
$events = implode(',', array_map(function($x) { return "'$x'"; }, $pp_events));
$pick = mysql_query("select startPrice from pick where eventid IN ($events)");
$product = 1;
while ($row = mysql_fetch_assoc($pick)) {
$product = $row['startPrice'];
}
echo $product;