php, keeping highest value out of multi-dimensional array

Question

I have a multidimensional array looking like this:

Array
(
    [0] => Array
        (
            [name] => name1
            [sha1] => sha1
            [size] => 693989968
        )

    [1] => Array
        (
            [name] => name1
            [sha1] => sha2
            [size] => 757204238
        )

    [2] => Array
        (
            [name] => name2
            [sha1] => sha3
            [size] => 1068277922
        )

    [3] => Array
        (
            [name] => name3
            [sha1] => sha4
            [size] => 996843467
        )

The return of the wanted function should be sha2,sha3,sha4; when a name is in there more than once, the higher size should be kept.

I tried for some hours now, using asort, splitting into multiple array (for name,sha and size) but none have worked until now.

Sort the array by size. Then loop through the array, removing any duplicate names. — Barmar, May 30 '17 at 18:26

score 0 · Accepted Answer · answered May 30 '17 at 18:50

$output_array=array();
$a = array(
 array(
   "name" => "name1",
   "sha1" => "sha1",
   "size" => 693989968
 ),
 array(
   "name" => "name1",
   "sha1" => "sha2",
   "size" => 757204238
 ),
 array(
   "name" => "name2",
   "sha1" => "sha3",
   "size" => 1068277922
 ),
 array(
   "name" => "name3",
   "sha1" => "sha4",
   "size" => 996843467
 )
);
foreach($a as $item){
  //item to check
  $item_tc = @$output_array[$item['name']]; //names with empty string will be discarded
  //by using @ to suppress errors.
  if($item_tc){
      print($item['size'].'n');
      print($item_tc['size']);
      if($item['size'] > $item_tc['size']){
           $output_array[$item['name']] = $item;
              //print_r($item);

       }
    }else{
      $output_array[$item['name']] = $item; 
    }
}
print_r($output_array);

The output is:

Array (
  [name1] => Array ( 
    [name] => name1 
    [sha1] => sha2 
    [size] => 757204238 
   ) 
   [name2] => Array (
    [name] => name2 
    [sha1] => sha3 
    [size] => 1068277922 
  ) 
  [name3] => Array ( 
    [name] => name3 
    [sha1] => sha4 
    [size] => 996843467 
  ) 
)

great, that works just fine for me, many thanks for your fast help! — Jan Allen, May 30 '17 at 19:50

php, keeping highest value out of multi-dimensional array

1 Answers1