Group array base on key value

Question

Yes, this has been answered countless times by using different methods, in most cases it works but not on my case, please allow me to explain.

I'm building an array from a CSV file, that was the easy part, the difficult part is, I have is that I have to build another array from the first array grouping the results based on one key value, the problem is that this value is not an array, nor a simple string...
This is a sample from the array of the CSV file

[0] => Array
     (
       [key_1] => FOO
       [cats] => /30/
       [key_2] => FTU-1
     )
[1] => Array
     (
       [key_1] => FOO
       [cats] => /30/
       [key_2] => FTU-2
     )
[2] => Array
     (
       [key_1] => FOO
       [cats] => /30/10/
       [key_2] => FTU-3
     )
[3] => Array
     (
       [key_1] => FOO
       [cats] => /15/
       [key_2] => FTU-4
     )
[4] => Array
     (
       [key_1] => FOO
       [cats] => /10/
       [key_2] => FTU-5
     )
[0] => Array
     (
       [key_1] => FOO
       [cats] => /15/
       [key_2] => FTU-6
     )

The final array has to look like this based on the column cats:

[30] => Array 
        (
           [0] => Array 
                 (
                   [key_1] => FOO
                   [cats] => /30/
                   [key_2] => FTU-1
                 )
           [1] => Array
                 (
                   [key_1] => FOO
                   [cats] => /30/
                   [key_2] => FTU-2
                 )
           [1] => Array
                 (
                   [key_1] => FOO
                   [cats] => /30/10/
                   [key_2] => FTU-3
                 )
[15] => Array 
        (
           [0] => Array 
                 (
                   [key_1] => FOO
                   [cats] => /15/
                   [key_2] => FTU-4
                 )
           [1] => Array
                 (
                   [key_1] => FOO
                   [cats] => /15/
                   [key_2] => FTU-6
                 )
[10] => Array 
        (
           [0] => Array 
                 (
                   [key_1] => FOO
                   [cats] => /30/10/
                   [key_2] => FTU-3
                 )
           [1] => Array
                 (
                   [key_1] => FOO
                   [cats] => /10/
                   [key_2] => FTU-5
                 )

I was looking in to this This answer which is the closest to what I need, but didn't work, that's why I'm asking for help.

Update: I think I just solved it...

foreach($firstarr as $k => $v) {
  $cats = array_filter(explode('/', $v['cats']));
  foreach($cats as $ks=>$vs) {
    if(stripos($v['cats'], $vs)){
      $pp[$vs][] = $v;
    }
  }
}

looking good.

Maxim Tkach · Answer 1 · 2016-05-15T21:05:03.437

Maybe you help this code:

function arrayByOneKey($array, $keyName)
{
    $result = [];
    foreach ($array as $item)
    {
        $keys = explode('/', (string)$item[$keyName]);
        foreach($keys as $key)
        {
            if($key == '')
            {
                continue;
            }
            $result[$key][] = $item;
        }
    }
    return $result;
}

$array = [
    [
        'key_1' => 'FOO',
        'key_2' => 'FTU-1',
        'cats' => '/15/'
    ],
    [
        'key_1' => 'FOO',
        'key_2' => 'FTU-2',
        'cats' => '/15/'
    ],
    [
        'key_1' => 'FOO',
        'key_2' => 'FTU-3',
        'cats' => '/30/10/'
    ],
    [
        'key_1' => 'FOO',
        'key_2' => 'FTU-4',
        'cats' => '/30/10/0'
    ]
];

$array = arrayByOneKey($array, 'cats');
var_dump($array);

Result:

array(4) {
  [15]=>
  array(2) {
    [0]=>
    array(3) {
      ["key_1"]=>
      string(3) "FOO"
      ["key_2"]=>
      string(5) "FTU-1"
      ["cats"]=>
      string(4) "/15/"
    }
    [1]=>
    array(3) {
      ["key_1"]=>
      string(3) "FOO"
      ["key_2"]=>
      string(5) "FTU-2"
      ["cats"]=>
      string(4) "/15/"
    }
  }
  [30]=>
  array(2) {
    [0]=>
    array(3) {
      ["key_1"]=>
      string(3) "FOO"
      ["key_2"]=>
      string(5) "FTU-3"
      ["cats"]=>
      string(7) "/30/10/"
    }
    [1]=>
    array(3) {
      ["key_1"]=>
      string(3) "FOO"
      ["key_2"]=>
      string(5) "FTU-4"
      ["cats"]=>
      string(8) "/30/10/0"
    }
  }
  [10]=>
  array(2) {
    [0]=>
    array(3) {
      ["key_1"]=>
      string(3) "FOO"
      ["key_2"]=>
      string(5) "FTU-3"
      ["cats"]=>
      string(7) "/30/10/"
    }
    [1]=>
    array(3) {
      ["key_1"]=>
      string(3) "FOO"
      ["key_2"]=>
      string(5) "FTU-4"
      ["cats"]=>
      string(8) "/30/10/0"
    }
  }
  [0]=>
  array(1) {
    [0]=>
    array(3) {
      ["key_1"]=>
      string(3) "FOO"
      ["key_2"]=>
      string(5) "FTU-4"
      ["cats"]=>
      string(8) "/30/10/0"
    }
  }
}

UPDATE

array_filter - elegant solution BUT category with id 0 will be ignored. And if so, then !empty($key) In the cycle better than array_filter - as it also passes through the array elements

This is the same logic on my update,. see, the if($key == "") in your code, instead I'm using array_filter() which serves the same purpose, your answer was posted a min after my update, SO doesn't allow me to choose an answer just yet... — Tanker, May 15 '16 at 20:30
array_filter - elegant solution BUT category with id 0 will be ignored. And if so, then !empty($key) In the cycle better than array_filter - as it also passes through the array elements — Maxim Tkach, May 15 '16 at 20:35

score 0 · Answer 2 · answered May 15 '16 at 20:05

0

You can get the key from explode('/', $item['cats'])[1]:

$newArray = [];
foreach($originalArray as $item) {
    $key = explode('/', $item['cats'])[1];
    $newArray[$key][] = $item;
}

answered May 15 '16 at 20:05

Fabricator

12,381
2
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score 0 · Answer 3 · answered May 15 '16 at 21:05

This may be a twisted work-around but I am willing to bet it does the trick:

        <?php

        $arrResultant = array();

        foreach($arr as $intKey=>$arrData){
            $stripped   = preg_replace("#^\/#", "", $arrData['cats']);
            $arrParts   = preg_split("#\/#", $stripped);
            $intCat1    = isset($arrParts[0])? $arrParts[0]:null;
            $intCat2    = isset($arrParts[1])? $arrParts[1]:null;
            if(!array_key_exists($intCat1, $arrResultant)){
                $arrResultant[$intCat1] = array();
                if( stristr($arrData["cats"], $intCat1) ){
                    $arrResultant[$intCat1][] = $arrData;
                }
            }else{
                if( stristr( $arrData["cats"], $intCat1) ){
                    $arrResultant[$intCat1][] = $arrData;
                }
            }
            if(!array_key_exists($intCat2, $arrResultant) && !is_null($intCat2)){
                $arrResultant[$intCat2] = array();
                if( stristr($arrData["cats"], $intCat2) ){
                    $arrResultant[$intCat2][] = $arrData;
                }
            }else{
                if( stristr( $arrData["cats"], $intCat2) ){
                    $arrResultant[$intCat2][] = $arrData;
                }
            }
        }

        var_dump($arrResultant);

Try it out and let us know how it went....

Group array base on key value

3 Answers3