Collecting values from a multidimensional array using foreach loops

Question

There is an array which is built looks like the following (with some more values which i left away for this example):

    Array
    (
        [0] => Array
            (
                [id] => 44
                [cars] => Array
                    (
                        [0] => Array
                            (
                                [id] => 38
                            )

                        [1] Array
                            (
                                [id] => 39
                            )
                    )

            )

        [1] => Array
            (
                [id] => 45
                [cars] => Array
                    (
                        [0] => Array
                            (
                                [id] =>136
                            )

                        [1] =>Array
                            (
                                [id] =>137
                            )

                        [2] =>Array
                            (
                                [id] =>138
                            )
                    )
            )
)

I want to build another array from the above in the following form:

Array

    (
       [0] =>  Array 
           (
               ['car_filter_sort_id'] => 44
               ['car_id'] => 38
           )
       [1] =>  Array 
           (
               ['car_filter_sort_id'] => 44
               ['car_id'] => 39
           )
       [2] =>  Array 
           (
               ['car_filter_sort_id'] => 45
               ['car_id'] => 136
           )
       [3] =>  Array 
           (
               ['car_filter_sort_id'] => 45
               ['car_id'] => 137
           )
       [4] =>  Array 
           (
               ['car_filter_sort_id'] => 45
               ['car_id'] => 138
           )
    )

I tried to achieve this with following function:

foreach($filterSortSaveArray as $filterSortSaveArray['cars'] => $value){
  $id =  $filterSortSaveArray['id'];
  foreach($value['cars'] as $value => $car){
    $field_values['car_filter_sort_id'] = $id;
    $field_values['car_id'] =  $car['id'];
  }
}

But the the result differs from what I have expected. Any suggestions?

Ruslan Osmanov · Accepted Answer · 2016-11-04 17:43:28Z

2

There are two big issues in your code. First, are you referencing undefined value with $filterSortSaveArray['cars'], since there is no 'cars' key in the first level of the original array. Second, by assigning values to $field_values['car_filter_sort_id'] and $field_values['car_id'] in the loop you are just overriding them in each iteration. You need to push the values into an array using []= operator (which is equivalent to applying array_push()).

Try this:

$result = [];

foreach($filterSortSaveArray as $k => $v) {
  if (!is_array($v['cars']))
    continue;

  $id = $v['id'];

  foreach ($v['cars'] as $i => $car){
    $result[] = [
      'car_filter_sort_id' => $id,
      'car_id' =>  $car['id']
    ];
  }
}

answered Nov 4, 2016 at 17:43

Ruslan Osmanov

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1 Comment

Marcel Wasilewski Over a year ago

Great, this worked out. And thank you very much for the explanation :)

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