Multiplying elements in an php array

Question

I have a really simple question but for some reason the output is not what I want. I have 2 arrays:

total_hours = array(10, 20, 30);
hourly_rate = array(15, 10, 15);

So what I want to work out is how to multiple the corresponding element of total_hours with the hourly_rate (e.g. element 1: 10*15 = 150) then put this into an array called total_sum (total_sum has been initialized) . This is what I've done so far:

$total_sum = 0;
for($i=0; $i < sizeof($hourly_rate); $i++) {
    for($a=0; $a < sizeof($total_hours); $a++) {
        $total_sum = ($hourly_rate[$i]*$total_hours[$a]); 
    } 
    $total_pay[] = $total_sum;    
}

At the moment I get 0 and don't understand why.

Many thanks!

Please clarify your question. Your code says total sum is an integer not an array. Also, what's this about 0? Your result seems to be an array. — Brad Koch
– Brad Koch, Commented Mar 10, 2013 at 17:33
My apologies, ignore the total sum. Also I get 0 when I do a print statement. — user2093306
– user2093306, Commented Mar 10, 2013 at 17:46

MetalRain · Accepted Answer · 2013-03-10 17:37:49Z

1

You can use array_map with anonymous function to multiply hours with rates. array_map iterates over given arrays and returns result as array. Look http://php.net/manual/en/function.array-map.php for more info.

$total_hours = array(10, 20, 30);
$hourly_rate = array(15, 10, 15);    

$total_pay = array_map(function($hour, $rate) {
    return $hour * $rate;
}, $total_hours, $hourly_rate);

answered Mar 10, 2013 at 17:37

MetalRain

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Comments

Community · Accepted Answer · 2017-05-23 12:04:53Z

0

The following is based on this answer by Aarolama Bluenk, and should work as long as both arrays are the same size:

for($i = 0; $i < count($total_hours); $i++) {
    $result[] = $total_hours[$i] * $hourly_rate[$i];
}

edited May 23, 2017 at 12:04

CommunityBot

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answered Mar 10, 2013 at 17:37

Vineet1982

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Comments

Daedalus · Accepted Answer · 2013-03-10 17:33:19Z

0

You don't want to have two loops, just one:

$total_pay = array();
for($i=0; $i < count($hourly_rate); $i++) {
  $total_pay[] = $hourly_rate[$i]*$total_hours[$i]; 
}

To get the sum of your final array, use array_sum.

edited Mar 10, 2013 at 17:33

answered Mar 10, 2013 at 17:24

Daedalus

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2 Comments

user2093306 Over a year ago

I've tried your suggestion but now for some reason it iterates 3 times and I have no idea why, don't suppose you have any idea?

Daedalus Over a year ago

It iterates three times because your array only has three elements in it. You wanted to multiply two arrays (each with three elements) together, so you only want to loop three times to make that happen.

Mark Baker · Accepted Answer · 2013-03-10 17:37:55Z

0

$total_hours = array(10, 20, 30);
$hourly_rate = array(15, 10, 15);

$mi = new MultipleIterator();
$mi->attachIterator(new ArrayIterator($total_hours));
$mi->attachIterator(new ArrayIterator($hourly_rate));

$total_pay = array();
foreach($mi as $details) {
    $total_pay[] = $details[0] * $details[1];
}

answered Mar 10, 2013 at 17:37

Mark Baker

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