Possible Duplicate:

PHP: How to sum values of the array of the same key

I am looking for an `array_merge()`

function that does NOT replace values, but ADDS them.

Example, this is the code I am trying:

```
echo "<pre>";
$a1 = array(
"a" => 2
,"b" => 0
,"c" => 5
);
$a2 = array(
"a" => 3
,"b" => 9
,"c" => 7
,"d" => 10
);
$a3 = array_merge($a1, $a2);
print_r($a3);
```

Sadly, this outputs this:

```
Array
(
[a] => 3
[b] => 9
[c] => 7
[d] => 10
)
```

I then tried, instead of `array_merge`

, just simply adding the two arrays

```
$a3 = $a1 + $a2;
```

But this outputs

```
Array
(
[a] => 2
[b] => 0
[c] => 5
[d] => 10
)
```

What I truly want is to be able to pass as many arrays as needed, and then get their sum. So in my example, I want the output to be:

```
Array
(
[a] => 5
[b] => 9
[c] => 12
[d] => 10
)
```

Of course I can schlepp and build some function with many `foreach`

etc, but am looking or a smarter, cleaner solution. Thanks for any pointers!

```
$sums = array();
foreach (array_keys($a1 + $a2) as $key) {
$sums[$key] = (isset($a1[$key]) ? $a1[$key] : 0) + (isset($a2[$key]) ? $a2[$key] : 0);
}
```

You *could* shorten this to the following using the error suppression operator, but it should be considered ugly:

```
$sums = array();
foreach (array_keys($a1 + $a2) as $key) {
$sums[$key] = @($a1[$key] + $a2[$key]);
}
```

Alternatively, some mapping:

```
$keys = array_fill_keys(array_keys($a1 + $a2), 0);
$sums = array_map(function ($a1, $a2) { return $a1 + $a2; }, array_merge($keys, $a1), array_merge($keys, $a2));
```

Or sort of a combination of both solutions:

```
$sums = array_fill_keys(array_keys($a1 + $a2), 0);
array_walk($sums, function (&$value, $key, $arrs) { $value = @($arrs[0][$key] + $arrs[1][$key]); }, array($a1, $a2));
```

I think these are concise enough to adapt one of them on the spot whenever needed, but to put it in terms of a function that accepts an unlimited number of arrays and sums them:

```
function array_sum_identical_keys() {
$arrays = func_get_args();
$keys = array_keys(array_reduce($arrays, function ($keys, $arr) { return $keys + $arr; }, array()));
$sums = array();
foreach ($keys as $key) {
$sums[$key] = array_reduce($arrays, function ($sum, $arr) use ($key) { return $sum + @$arr[$key]; });
}
return $sums;
}
```

### Answer：

My contribution:

```
function array_merge_numeric_values()
{
$arrays = func_get_args();
$merged = array();
foreach ($arrays as $array)
{
foreach ($array as $key => $value)
{
if ( ! is_numeric($value))
{
continue;
}
if ( ! isset($merged[$key]))
{
$merged[$key] = $value;
}
else
{
$merged[$key] += $value;
}
}
}
return $merged;
}
```

Pass as many arrays to it as you want. Feel free to add some more defense, ability to accept multidimensional arrays, or type checking.

### Answer：

its not so complicate

do something like:

```
$a3 = $a1;
foreach($a2 as $k => $v) {
if(array_key_exists($k, $a3)) {
$a3[$k] += $v;
} else {
$a3[$k] = $v;
}
}
```

### Answer：

You can use array_push function.I hope it will help you

```
foreach($a2 as $a2){
array_push($a1, $a2);
}
print_r($a1);
Output:
Array
(
[a] => 2
[b] => 0
[c] => 5
[0] => 3
[1] => 9
[2] => 7
[3] => 10
)
```

OR

you can change your logic in key value with numbers.It works even it have same number as follows:

```
<?php
$beginning = array(1 => 'foo');
$end = array(1 => 'bar');
$result = array_merge((array)$beginning, (array)$end);
print_r($result);
?>
Output:
Array (
[0] => foo
[1] => bar
)
```

Enjoy!!!!!!!!!!!!!!