How to generate an array using 3rd-level values of a multi-dimensional array

Question

As shown below I have a multi-dimensional array with an associative array in the third level that I am trying to manipulate based on gamesCount. I want to generate a new array of items with the highest gamesCount in each sport. Is there an efficient way to this without going overkill?

EDIT: It could be n number of sports hence the goal is to find the max number for gameCounts for each sport.

Initial array:

$array = [
    [
        ["sport" => "soccer", "gamesCount" => 5, "gamesId" => 1],
        ["sport" => "soccer", "gamesCount" => 3, "gamesId" => 2],
        ["sport" => "soccer", "gamesCount" => 10, "gamesId" => 3],
        ["sport" => "soccer", "gamesCount" => 10, "gamesId" => 4],
    ],
    [
        ["sport" => "basketball", "gamesCount" => 1, "gamesId" => 5],
        ["sport" => "basketball", "gamesCount" => 3, "gamesId" => 6],
        ["sport" => "basketball", "gamesCount" => 3, "gamesId" => 7],
        ["sport" => "basketball", "gamesCount" => 8, "gamesId" => 8],
    ]
];

Desired Result:

array(3) {
      [0]=>
      array(3) {
        ["sport"]=>
        string(6) "soccer"
        ["gamesCount"]=>
        int(10)
        ["gamesId"]=>
        int(3)
      }
      [1]=>
      array(3) {
        ["sport"]=>
        string(6) "soccer"
        ["gamesCount"]=>
        int(10)
        ["gamesId"]=>
        int(4)
      }
      [2]=>
      array(3) {
        ["sport"]=>
        string(10) "basketball"
        ["gamesCount"]=>
        int(5)
        ["gamesId"]=>
        int(8)
      }
}

LF-DevJourney · Accepted Answer · 2017-05-19 06:58:02Z

1

try this, check the live demo

$result = [];
foreach($array as $v)
{
$max = max(array_column($v, 'gamesCount'));
    $result = array_merge($result, array_filter($v, function($value)use($max){return $value['gamesCount'] == $max;}));
}
var_dump($result);

edited May 19, 2017 at 6:58

answered May 19, 2017 at 5:57

LF-DevJourney

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7 Comments

MaryCoding Over a year ago

I am getting an error: Warning: max(): Array must contain at least one element for this line return max(array_column($v, 'gameCount'));. I double checked and $array does contain an array an its elements.

LF-DevJourney Over a year ago

@MaryCoding there is a error, it should be gamesCount in the code.

MaryCoding Over a year ago

It yields an empty array. Check this GIST

mickmackusa Over a year ago

@KrisRoofe No Kris, check the edit history. Same structure. Now she is using my php-ready variable instead of the print_r output that she first posted. The sports were always in two separate subarrays.

LF-DevJourney Over a year ago

@mickmackusa sorry, I miss use a function. check it now

|

Community · Accepted Answer · 2017-05-23 11:54:59Z

1

Input:

$array=[
    [
        ["sport"=>"soccer","gamesCount"=>5,"gamesId"=>1],
        ["sport"=>"soccer","gamesCount"=>3,"gamesId"=>2],
        ["sport"=>"soccer","gamesCount"=>10,"gamesId"=>3],
        ["sport"=>"soccer","gamesCount"=>10,"gamesId"=>4]
    ],
    [
        ["sport"=>"basketball","gamesCount"=>1,"gamesId"=>5],
        ["sport"=>"basketball","gamesCount"=>3,"gamesId"=>6],
        ["sport"=>"basketball","gamesCount"=>3,"gamesId"=>7],
        ["sport"=>"basketball","gamesCount"=>8,"gamesId"=>8]
    ]
];

Method #1 "The easiest to read version with two loops" (Demo)

foreach($array as $sport_array){
    $most_in_sport=max(array_column($sport_array,'gamesCount'));  // get highest gamesCount in sport's subarray      
    foreach($sport_array as $sport_row){
        if($sport_row['gamesCount']==$most_in_sport){  // only keep a sport's subarray (row) if its gamesCount is the highest in the sport
            $most_per_sport[]=$sport_row;
        }
    }
}
var_export($most_per_sport);

Method #2: "The obscenely convoluted variadic one-liner" php minimum version: 5.6 (For those who wish who do not fear the one-liner apocalypse -- reference: 1st comment @ https://stackoverflow.com/a/43950486/2943403.) (Demo)

var_export(array_merge(...array_map(function($sport_array){$most_in_sport=max(array_column($sport_array,'gamesCount')); return array_filter($sport_array,function($sport_row)use($most_in_sport){return $sport_row['gamesCount']==$most_in_sport;});},$array)));

Output:

array (
  0 => 
  array (
    'sport' => 'soccer',
    'gamesCount' => 10,
    'gamesId' => 3,
  ),
  1 => 
  array (
    'sport' => 'soccer',
    'gamesCount' => 10,
    'gamesId' => 4,
  ),
  2 => 
  array (
    'sport' => 'basketball',
    'gamesCount' => 8,
    'gamesId' => 8,
  ),
)

Deciding which method to use is up to each individual programmer. The first method will be most efficient and IMO easiest to comprehend. The second will generate less global variables and require less lines of code. If you are trying to avoid "over-kill" Method #1 cannot be beaten.

edited May 23, 2017 at 11:54

CommunityBot

11 silver badge

answered May 19, 2017 at 6:24

mickmackusa♦

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5 Comments

MaryCoding Over a year ago

This only handles two arrays but thing is that it could be n number of arrays. E.g. basketball, soccer, baseball, etc.

mickmackusa Over a year ago

@MaryCoding What do you think now? I have provided two methods to suit a range of php versions.

MaryCoding Over a year ago

This got me closer to a result but this is line is hardcoded $top3 = array_slice($array, 0, 3); // extract the top 3 subarrays. It could be n number of sports hence n number of max for gameCounts. Specially if there are the same value for some.

mickmackusa Over a year ago

@MaryCoding You never said in your question where to draw the line, so I replicated your desired result. You can change it to whatever you like.

MaryCoding Over a year ago

You are correct. My apologies. I will update the question. Thanks.

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