How to search specific index in multidimensional array and update its value?

Question

Below is my code:

I get ingredients records from database, each of the record contains id, name and weight and category field.

I want to sum the weights of all the ingredients having same id

$weights=array();

    foreach($ingredients as $ingredient)
    {
         $key=array_search($ingredient['id'],$weights);
          if($key==true)
          {
             //Sum weights    
          }
          else
          {
            $new_ingredient=array('id'=>$ingredient['id'],'weight'=>$ingredient['weight']);
            array_push($weights, $new_ingredient);
          }
    }

print_r($weights);

Currently, I have following:

Meat:

1KG Chicken

3KG Chicken

What I want is:

4KG Chicken

and so on for other categories of ingredients.

So the above foreach loop will run for each of the ingredient category.

I can't somehow handle how to do that, using multidimensional array. Can anyone help, how would I do that? Please let me know if you need more details. Thanks.

No the scenario is different here...I know that is solution in many cases but not applicable here. Why not applicable? I can't explain but I am sure db query solution is not applicable here. I want to sum that using arrays. Thanks for your help. — Hammad
– Hammad, Commented Jun 4, 2014 at 8:06
So what you're after is to remove all duplicate items and calculate their sums to the remaining item? — Antti29
– Antti29, Commented Jun 4, 2014 at 8:08
Yes @Antti29. That is what I want, but only using similar way I wrote in code, not using SQL sum function. — Hammad
– Hammad, Commented Jun 4, 2014 at 8:09
maybe you could post a sample you a simple select db like: var_dump($records_from_mysql_select); — user1978142
– user1978142, Commented Jun 4, 2014 at 8:20

user1978142 · Accepted Answer · 2014-06-04 08:23:47Z

To sum them all up, you need to create another array from that, them sum the weight key while inside the loop. Consider this example:

// if your db query result looks like this (we dont know what your original data looks like)
// sample data from select * from ingredients
$values_from_db = array(
    array(
        'id' => 1,
        'name' => 'Chicken',
        'unit' => 'KG',
        'weight' => 100,
    ),
    array(
        'id' => 2,
        'name' => 'Pork',
        'unit' => 'KG',
        'weight' => 300,
    ),
    array(
        'id' => 3,
        'name' => 'Beef',
        'unit' => 'KG',
        'weight' => 400,
    ),
    array(
        'id' => 1,
        'name' => 'Chicken',
        'unit' => 'KG',
        'weight' => 100,
    ),
    array(
        'id' => 2,
        'name' => 'Pork',
        'unit' => 'KG',
        'weight' => 200,
    ),
);

$data = array();
foreach($values_from_db as $key => $value) {
    $current_id = $value['id'];
    if(!isset($data[$current_id]['weight'])) $data[$current_id]['weight'] = 0;
    $data[$current_id]['id'] = $current_id;
    $data[$current_id]['name'] = $value['name'];
    $data[$current_id]['unit'] = $value['unit'];
    $data[$current_id]['weight'] += $value['weight'];
}

echo "<pre>";
print_r($data);
echo "</pre>";

Sample Output:

Array
(
    [1] => Array
        (
            [weight] => 200
            [id] => 1
            [name] => Chicken
            [unit] => KG
        )

    [2] => Array
        (
            [weight] => 500
            [id] => 2
            [name] => Pork
            [unit] => KG
        )

    [3] => Array
        (
            [weight] => 400
            [id] => 3
            [name] => Beef
            [unit] => KG
        )

)

Antti29 · Accepted Answer · 2014-06-04 08:22:16Z

0

If the key of the result array is not important, you could do the following:

$result = array();

foreach ($ingredients as $ingredient) {
    if (isset($result[$ingredient['id']]))
        $result[$ingredient['id']]['weight'] += $ingredient['weight'];
    else
        $result[$ingredient['id']] = $ingredient;
}

The id of the item is stored in the key of $result and used when checking if the item is already there.

answered Jun 4, 2014 at 8:22

Antti29

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