Sum of arrays?

[PeaceFrog]

Hi,

Googling and lots of trying, didnt really get me anywhere to what i would like, hopefully someone can help point me in the right direction.

For testing purposes i have the following array:

$test = array(array(a,1,2,3,4),array(b,1,2,3,4),array(b,1,2,3,4)); 

I would like to create a function, that adds up the values (the numbers) of each array, if the first value already exists in the array (the letters), so that above posted array, would become:

[PHP}
$testAgain = array(array(a,1,2,3,4),array(b,2,4,6,8));
[/PHP]

I've tried to first get the letters in a new array, and make sure that's unique, and then go through $test again, to, if a letter matches, add the values up...but well, that doesnt really seem to work.

Anyone got a hint for me?

Thanks!


peace

[JunkMale]

array_sum() does that as for your array structure, wouldn't

$test = array( "a"=>array(1,2,3,4),"b"=>array(1,2,3,4),"c"=>array(1,2,3,4) );
$a = array_sum( $test["a"] );
echo "Sum of values in array 'a' = ".$a; 

work for you?

[NogDog]

This might be a case of needing to understand the context, and perhaps finding a very different solution. For instance, if this array you're dealing with is the result of a database query, my suspicion is that it could be handled more easily and efficiently at the database level, such as with a GROUP BY query with SUM() functions for each of those numeric fields.

[PeaceFrog]

Hi,

Thanks for your quick reply.

You solution wouldnt work for me though, it gets the sum of the array, where i would like to add up values. The array (key?) holds an article number, the numbers are quantities of variations of article; if an article number is being inserted in the array twice, i would like to add up the quantities, perhaps something looking like:

$test = array ("cube"=>array("red"=>1,"blue"=>1), "ball"=>array("red"=>1,"blue"=>1), "cube"=>array("red"=>1,"blue"=>2) ); 

As it is now, the php just echoes what it sees, so it would list "cube" twice, with its quantities, where i would like to have it listed just once, with the quantities added up, so that the array would look like:

$test = array ("cube"=>array("red"=>2,"blue"=>3), ("ball"=>array("red"=>1,"blue"=>1) ); 

Is this possible or is there another way of achieving this? Perhaps already "sort" the array when inserting the new values?

peace

[PeaceFrog]

The array is not a result of a database query. I get the data from a form, which saves the data in a (temp) array, which gets pushed into the array i want to sort ($test in this case)



peace

[NogDog]

Something like this, perhaps?

<?php
$test = array(
   array('a', 1, 2, 3),
   array('b', 2, 4, 6),
   array('b', 3, 4, 5),
   array('a', 1, 0, 1)
);
$sorted = array();
foreach($test as $entry)
{
   $key = array_shift($entry);
   if(isset($sorted[$key]))
   {
      foreach($entry as $ix => $value)
      {
         $sorted[$key][$ix] += $value;
      }
   }
   else
   {
      $sorted[$key] = $entry;
   }
}
echo "<pre>".print_r($sorted, 1)."</pre>";

Output:

Array
(
    [a] => Array
        (
            [0] => 2
            [1] => 2
            [2] => 4
        )

    [b] => Array
        (
            [0] => 5
            [1] => 8
            [2] => 11
        )

)

[PeaceFrog]

Hi,

That is exactly what im looking for!

Unfortunately i have to go to work in a minute, so i don't have time to try it out at the moment, but i will when i get back, and will let you know!

Thanks ever so much!


peace

[PeaceFrog]

The script NogDog posted works well for me, however i run into the problem of how to echo the key and the values.

I would like to echo out the key (the product id) and the values (quantities of different variations of that product), something like:

Product: a, Red: 2, Blue, 3, Yellow, 4

I've been trying with key(), but that only returns 0 ?? I've been trying quite a few things, obviously also googled it and searched on the forums here, but i cant seem to find the answer i'm looking for. I either get no result, 0 or 'Array' when i echo.


Would appreciate it a lot if anyone could help me with some directions!



Thanks a lot!


peace

[NogDog]

In my previous example, you could do:

foreach($sorted as $id => $data)
{
   echo "<h4>Product #$id</h4>\n<ul>\n";
   foreach($data as $key => $total)
   {
      echo "<li>$key: $total</li>\n";
   }
   echo "</ul>\n";
} 

[PeaceFrog]

Thanks a lot NogDog, that works perfectly for me!

Fortunately, im almost done with the page im working on. A very heavy delivery as i'm pretty new to php and i'm trying to learn as i go (i have a different scripting background, but eager to learn PHP as well)

Now all i need to do is sort out this session issue, and i think im good to go.

Thanks again!


peace