I currently have two arrays, the key in each is a product id, whilst the value is the quantity:
$array_1 = ([10] => 1, [13] => 3, [27] => 1, [32] => 2);
$array_2 = ([8] => 1, [10] => 1, [12] => 1, [20] => 2, [27] => 1);
I want to combine the two array, but add the values together where the keys match. Is there a method to do this without iterating through the arrays?
The following is my belief on the shortest way to merge the two arrays together. There may be a built in function that I don't know about, but it will merge both arrays into $array_1.
foreach($array_1 as $k => $v)
foreach($array_2 as $i => $j)
if($k == $i) {
$array_1[$k] = $v + $j;
break;
}
EDIT- break when found.
EDIT-(Thanks to KC)
foreach($array_1 as $k => $v)
if(isset($array_2[$k])) {
$array_1[$k] += $array_2[$k];
unset($array_2[$k]);
}
foreach($array_2 as $k => $v)
$array_1[$k] = $v;
n*m in worst case? Whats about just foreach($array_1 as $k => $v) { if (isset($array_2[$key])) { /* add */ } else { /* not add */ }? Feels much more efficient. You can unset the keys in $array_2, that already found. The remaining $array_2 are "untouched keys"
PHPs native array functions provide a few ways to split up and group the arrays, but an addition isn't possible (array_sum doesn't really help).
So while we're at recommending the solution that you specifically not asked for, here's a shorter one:
foreach ($array_2 as $i=>$k) {
$array_1[$i] += $k;
}
"Without iterating" no. Even if you wrap them into functions such as array_map its an iteration (its only not visible in the code itself ;))
$result = array_merge_recursive($array_1, $array_2);
On unique key, this will leave it, as it is. On two identical keys, it will merge the both values together into an array. A nice solution in PHP5.3
$result = array_map (function ($item) {
return is_array($item)
? $item[0] + $item[1]
: $item;
}, $result);
The non-5.3 solution is not that ugly too
foreach ($result as &$item) {
if (is_array($item)) $item = $item[0] + $item[1];
}
Update:
If I read your question now, I doubt, that I understand what you mean by "add the values together". It makes not much sense to really add a product ID and a quantity together. However, just replace the + above with the operation of your needs :)
You can just use the built in merge function for arrays.
array_merge(array1,array2,array3...);
Using your array names here is how you do it
array_merge($array_1 , $array_1);
This is the Function:
<?php
function merge($array1, $array2)
{
if(sizeof($array1)>sizeof($array2))
{
echo $size = sizeof($array1);
}else{
$a = $array1;
$array1 = $array2;
$array2 = $a;
echo $size = sizeof($array1);
}
$keys2 = array_keys($array2);
for($i = 0;$i<$size;$i++)
{
$array1[$keys2[$i]] = $array1[$keys2[$i]] + $array2[$keys2[$i]];
}
$array1 = array_filter($array1);
return $array1;
}
?>
Taken From Here
and seems to me the most perfect solution.
