CODEWITHSUNDEEP
phparraysmultidimensional-arraysumgrouping
Michelle
Michelle

Reputation: 133

Group an array of objects by one property and sum another property within each group

I am trying to group items within a PHP foreach by their 'field->value' and get the sum of each group separately. This code below works, but I feel like there is a more efficient way of doing it?

$number_1 = 0;
$number_2 = 0;
$number_3 = 0;

foreach ( $fields as $field ) {   
  if($field->value == 1) {
    $number_1 += $field->number;
  }
  if($field->value == 2) {
    $number_2 += $field->number; 
  }
  if($field->value == 3) {
    $number_3 += $field->number; 
  }
  
}  

echo $number_1; 
echo $number_2; 
echo $number_3;

Upvotes: 0

Views: 8553

Answers (2)

Barmar
Barmar

Reputation: 780724

Don't use separate variables, use an array with $field->value as the index.

$numbers = array();
foreach ($fields as $field) {
    if (isset($numbers[$field->value])) {
        $numbers[$field->value] += $field->number;
    } else {
        $numbers[$field->value] = $field->number;
    }
}

Upvotes: 1

Andreas
Andreas

Reputation: 23958

In this case you can use variable variables.
Generally I would rather recommend an array but it's your choice. 

foreach ( $fields as $field ) {  
     ${"number_" . $field->value} += $field->number;
}

Array version. 

foreach ( $fields as $field ) {  
     $arr["number_" . $field->value] += $field->number;
}
//  Either output as array or extract values to separate variables.  

Echo $arr["number_1"];
//Or
Extract($arr);
Echo $number_1;

Edit had number where it should be value.

Upvotes: 2

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