How to summary same value in array using PHP?

Question

I have an array like this:

Array (
    [0] => Array
        (
            [code] => Red Rose
            [info] => 2
        )

    [1] => Array
        (
            [code] => Lily Flower
            [info] => 1
        )

    [2] => Array
        (
            [code] => Lily Flower
            [info] => 4
        )

    [3] => Array
        (
            [code] => Lily Flower
            [info] => 2
        )
)

I need my result to be like:

Red Rose (2)

Lily Flower (7)

I have been trying to use foreach, but with no success.

foreach($array as $rowjb):
   echo $rowjb['code']." (".$rowjb['info'].") </br>";
endforeach;

Red Rose (2)
Lily Flower (1)
Lily Flower (4)
Lily Flower (2)

Use the `code` as a `key` and sum the `info` for each iteration. Post `$array` as executable code and Ill show example.... if this is coming from a DB this could be done much easier. — user3783243, Jan 20 '21 at 16:58
Because you're just looping through the array you need to sum the values with the same 'code' values that array items have. — Erasus, Jan 20 '21 at 16:59
What have you tried to check why the given code does not aggregate anything? — Nico Haase, Jan 20 '21 at 17:16

GrumpyCrouton · Accepted Answer · 2021-01-20T17:11:47.963

I would loop through your array and create a new array in the format you need.

$new_array = [];
foreach($array as $row) {
    
    $code = $row['code'];
    $info = $row['info'];

    //check if `code` key exists in `$new_array`, if not, create it
    if(!array_key_exists($code, $new_array)) {
        $new_array[$code] = 0;
    }
    
    //add up `info` values per-key
    $new_array[$code] += $info;
}

/* result looks like
    Array
    (
        [Red Nose] => 2
        [Lily Flower] => 7
    )
*/

This will create a new array with your code value as the key, and will add up all the numbers per-key for info.

Then, getting your output is trivial;

foreach($new_array as $code => $info) {
    echo "{$code} ({$info})<br>";
}

Output

Red Nose (2)<br>Lily Flower (7)<br>

RiggsFolly · Answer 2 · 2021-01-20T17:22:56.147

You will have to accumulate the total and work out when the code changes

$array = [['code'=>'Red Nose', 'info'=> 2],
        ['code'=>'Lily Flower', 'info'=> 1],
        ['code'=>'Lily Flower', 'info'=> 4],
        ['code'=>'Lily Flower', 'info'=> 2]
    ];

$last_code = $array[0]['code'];
$abacus = 0;
foreach( $array as $rowjb){
    
    if ( $last_code != $rowjb['code'] ) {
        echo $last_code . " (" . $abacus . ") <br>\n";    
        $abacus = 0;
        $last_code = $rowjb['code'];
    }

    $abacus += $rowjb['info'];
}
echo $last_code . " (" . $abacus . ") <br>\n";

RESULT

Red Nose (2) <br>
Lily Flower (7) <br>

Progrock · Answer 3 · 2021-01-20T18:04:31.833

You can use an intermediate array, to store associate each value for your codes (providing they are valid array keys). And then sum them.

<?php

$array = [
    ['code'=>'Red Rose', 'info'=> 2],
    ['code'=>'Lily Flower', 'info'=> 1],
    ['code'=>'Lily Flower', 'info'=> 4],
    ['code'=>'Lily Flower', 'info'=> 2]
];

foreach($array as $item) {
    $code_infos[$item['code']][] = $item['info'];
}

$code_info_sums = array_map('array_sum', $code_infos);
var_export($code_info_sums);

Output:

array (
    'Red Rose' => 2,
    'Lily Flower' => 7,
  )

The intermediate array:

var_export($code_infos);

Output:

array (
  'Red Rose' => 
  array (
    0 => 2,
  ),
  'Lily Flower' => 
  array (
    0 => 1,
    1 => 4,
    2 => 2,
  ),
)

To display you can just loop through the resultant array.

foreach($code_info_sums as $code => $count) {
    echo "$code ($count)\n";
}

Output:

Red Rose (2)
Lily Flower (7)

How to summary same value in array using PHP?

3 Answers3