Sum values of duplicate keys in a simple and single array and display that key only once in PHP

Question

I have an array created out of a string in my website:

$items = '"1010" => "3", "1010" => "1", "1020" => "2", "1030" => "6"'; //string
$items_element = array(); //this is the created array
$items_bits = explode(",", $items);
foreach ($items_bits as $i) {
    $i = str_replace('"', '', $i);
    $i_bobs = explode(" => ", $i);
    $items_element[$i_bobs[0]] = $i_bobs[1];
}

To get the results of this array, I use a foreach() loop:

foreach($items_element as $item_id => $item_count){
    echo $item_id.': '.$item_count.'</br>';
}

Right now, the result is coming up like this:

1010: 3

1010: 1

1020: 2

1030: 6

And I need all the duplicate keys to be displayed only once, but their values has to be summed with each others.

Example.:

1010: 4

1020: 2

1030: 6

How can I do something like this? I've tried it in many different ways but the truth is that I'm lost and don't know how to get this results. So I was hoping that someone could enlighten my mind here...

Possible duplicate of [How to merge two arrays by summing the merged values](http://stackoverflow.com/questions/6086267/how-to-merge-two-arrays-by-summing-the-merged-values) — H2ONOCK, Dec 07 '16 at 15:23
Thanks for your comment @H2ONOCK, I've seen a couple of questions similar to that one, but it was difficult for me to put in practice since the array's format were different in that example. — user3050478, Dec 07 '16 at 15:31

Jirka Hrazdil · Accepted Answer · 2016-12-07T18:31:21.363

2

Change your loop as follows:

foreach ($items_bits as $i) {
    $i = str_replace('"', '', $i);
    $i_bobs = explode(" => ", $i);
    if (!isset($items_element[trim($i_bobs[0])]))
        $items_element[trim($i_bobs[0])] = 0;
    $items_element[trim($i_bobs[0])] += (int)$i_bobs[1];
}

trim() is added, because the second index of your array started with space (e.g. " 1010" instead of "1010"). That's also why you got duplicates in resulting array. If it weren't the case, the key would be overwritten by the last occurrence.

edited Dec 07 '16 at 18:31

answered Dec 07 '16 at 15:23

Jirka Hrazdil

3,983
1
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I tested it here and it worked perfectly! Thanks. Forgive me for my lack of knowledge as I'm starting in the php language, so the function `trim()` is to remove spaces of strings? – user3050478 Dec 07 '16 at 15:28
1

@user3050478: Indeed, `trim()` removes whitespace characters (such as space, tab, new line, ...) from the beginning and the end of the string. See [documentation](http://php.net/trim) for more information. – Jirka Hrazdil Dec 07 '16 at 15:30
1

Well thank you so much @Jiri Hrazdil, you have no idea how much that served to me, not just to finish those lines of code, but I actually learned something out of it! – user3050478 Dec 07 '16 at 15:33

score 1 · Answer 2 · answered Dec 07 '16 at 16:29

1

$items = '"1010" => "3", "1010" => "1", "1020" => "2", "1030" => "6"'; //string
$items_element = array(); //this is the created array
$items_bits = explode(",", preg_replace('/\s+/', '', $items));

foreach($items_bits as $value) {
    $value_exploded = explode('=>', $value);

    $value_exploded_key = (int)str_replace('"', '', $value_exploded[0]);
    $value_exploded_value = (int)str_replace('"', '', $value_exploded[1]);
    $value_exploded_value = !isset($items_element[$value_exploded_key]) ? $value_exploded_value : $items_element[$value_exploded_key] + $value_exploded_value;

    $items_element[$value_exploded_key] = $value_exploded_value;
}

var_dump($items_element);

answered Dec 07 '16 at 16:29

Wolverine

1,712
1
15
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Thanks for sharing your method @Perumal93, I just quickly tested it and I could not notice any errors. I'll still use the first one though, since it was already applied to my codes and it looks quite simplier. – user3050478 Dec 07 '16 at 16:36
Yeah. The first one looks simpler. Even though it is so, I've shared my approach. I've used ternary expression rather than going for `if else` statements. Maybe that one makes it bit complicated for you. – Wolverine Dec 07 '16 at 16:38

Sum values of duplicate keys in a simple and single array and display that key only once in PHP

2 Answers2