combine array values in sub array?

Question

When I retrieve articles information from a mysql database I got an array like this:

Array
(
    [0] => Array
        (
            [CategoryID] => 3
            [CategoryName] => Test Category
            [Parent] => 0
            [Thumb] => 0
            [sort] => 8
            [ArticleID] => 2
            [ArticleCatgories] => 9,4,3
            [ArticleTitle] => vxcvxcvx
            [ArticleBody] => xcvxcvxcvxcv
            [InGroup] => 0
            [GroupID] => 0
            [Published] => 1
            [PublishTime] => 
            [TermID] => 11
            [TermSlug] => xcvxcvxcv
            [RelatedID] => 2
            [TermType] => article
        )

    [1] => Array
        (
            [CategoryID] => 4
            [CategoryName] => Test Image
            [Parent] => 0
            [Thumb] => 0
            [sort] => 4
            [ArticleID] => 2
            [ArticleCatgories] => 9,4,3
            [ArticleTitle] => vxcvxcvx
            [ArticleBody] => xcvxcvxcvxcv
            [InGroup] => 0
            [GroupID] => 0
            [Published] => 1
            [PublishTime] => 
            [TermID] => 11
            [TermSlug] => xcvxcvxcv
            [RelatedID] => 2
            [TermType] => article
        )

    [2] => Array
        (
            [CategoryID] => 9
            [CategoryName] => Test Images
            [Parent] => 0
            [Thumb] => 7
            [sort] => 2
            [ArticleID] => 2
            [ArticleCatgories] => 9,4,3
            [ArticleTitle] => vxcvxcvx
            [ArticleBody] => xcvxcvxcvxcv
            [InGroup] => 0
            [GroupID] => 0
            [Published] => 1
            [PublishTime] => 
            [TermID] => 11
            [TermSlug] => xcvxcvxcv
            [RelatedID] => 2
            [TermType] => article
        )
}

And because the article is in more than one category, it retrieve the article information more than once. What I need to do is to combine the category names into a sub array if they have the same ArticleID so the result become like:

Array
(
    [0] => Array
        (
            [CategoryName] => array('Test Category','Test Image','Test Images');
            [Parent] => 0
            [Thumb] => 0
            [sort] => 8
            [ArticleID] => 2
            [ArticleCatgories] => 9,4,3
            [ArticleTitle] => vxcvxcvx
            [ArticleBody] => xcvxcvxcvxcv
            [InGroup] => 0
            [GroupID] => 0
            [Published] => 1
            [PublishTime] => 
            [TermID] => 11
            [TermSlug] => xcvxcvxcv
            [RelatedID] => 2
            [TermType] => article
        )
}

Mysql has Group Concat. You will be much faster letting MySQL handle that instead of looping a larger result-set later in PHP — hakre
– hakre, Commented Oct 4, 2012 at 7:49

Ja͢ck · Accepted Answer · 2012-10-04 03:03:10Z

You can build a new array using ArticleID as the keys:

$final = array();
foreach ($rows as $row) {
    $id = $row['ArticleID'];
    if (isset($final[$id])) {
        // we've already seen this article
        // append to categoryname array
        $final[$id]['CategoryName'][] = $row['CategoryName'];
    } else {
        // this is the first article occurrence
        // turn categoryname into array first
        $row['CategoryName'] = array($row['CategoryName']);
        $final[$id] = $row;
    }
}

print_r($final);

Output based on your question:

Array
(
    [2] => Array
        (
            [CategoryID] => 3
            [CategoryName] => Array
                (
                    [0] => Test Category
                    [1] => Test Image
                    [2] => Test Images
                )

            [Parent] => 0
            [Thumb] => 0
            [sort] => 8
            [ArticleID] => 2
            [ArticleCatgories] => 9,4,3
            [ArticleTitle] => vxcvxcvx
            [ArticleBody] => xcvxcvxcvxcv
            [InGroup] => 0
            [GroupID] => 0
            [Published] => 1
            [PublishTime] =>
            [TermID] => 11
            [TermSlug] => xcvxcvxcv
            [RelatedID] => 2
            [TermType] => article
        )

)

Community · Accepted Answer · 2023-11-17 19:24:28Z

You can use array_reduce

$array = Array(
    "0" => Array("CategoryID" => 3,"CategoryName" => "Test Category","Parent" => 0,"Thumb" => 0,"sort" => 8,"ArticleID" => 2,"ArticleCatgories" => "9,4,3","ArticleTitle" => "vxcvxcvx","ArticleBody" => "xcvxcvxcvxcv","InGroup" => 0,"GroupID" => 0,"Published" => 1,"PublishTime" => null,"TermID" => 11,"TermSlug" => "xcvxcvxcv","RelatedID" => 2,"TermType" => "article"),
    "1" => Array("CategoryID" => 4,"CategoryName" => "Test Image","Parent" => 0,"Thumb" => 0,"sort" => 4,"ArticleID" => 3,"ArticleCatgories" => "9,4,3","ArticleTitle" => "vxcvxcvx","ArticleBody" => "xcvxcvxcvxcv","InGroup" => 0,"GroupID" => 0,"Published" => 1,"PublishTime" => null,"TermID" => 11,"TermSlug" => "xcvxcvxcv","RelatedID" => 2,"TermType" => "article"),
    "2" => Array("CategoryID" => 9,"CategoryName" => "Test Images","Parent" => 0,"Thumb" => 7,"sort" => 2,"ArticleID" => 2,"ArticleCatgories" => "9,4,3","ArticleTitle" => "vxcvxcvx","ArticleBody" => "xcvxcvxcvxcv","InGroup" => 0,"GroupID" => 0,"Published" => 1,"PublishTime" => null,"TermID" => 11,"TermSlug" => "xcvxcvxcv","RelatedID" => 2,"TermType" => "article"),
    "3" => Array("CategoryID" => 4,"CategoryName" => "Test A","Parent" => 0,"Thumb" => 0,"sort" => 4,"ArticleID" => 3,"ArticleCatgories" => "9,4,3","ArticleTitle" => "vxcvxcvx","ArticleBody" => "xcvxcvxcvxcv","InGroup" => 0,"GroupID" => 0,"Published" => 1,"PublishTime" => null,"TermID" => 11,"TermSlug" => "xcvxcvxcv","RelatedID" => 2,"TermType" => "article"),
    "4" => Array("CategoryID" => 9,"CategoryName" => "Test B","Parent" => 0,"Thumb" => 7,"sort" => 2,"ArticleID" => 2,"ArticleCatgories" => "9,4,3","ArticleTitle" => "vxcvxcvx","ArticleBody" => "xcvxcvxcvxcv","InGroup" => 0,"GroupID" => 0,"Published" => 1,"PublishTime" => null,"TermID" => 11,"TermSlug" => "xcvxcvxcv","RelatedID" => 2,"TermType" => "article")
);

$array = array_reduce($array, function ($a, $b) {
    is_null($a) ? $a = array() : null;
    if (!isset($a[$b['ArticleID']])) {
        $a[$b['ArticleID']] = $b ;
        $a[$b['ArticleID']]['CategoryName'] = array($b['CategoryName']);
    } else {
        $a[$b['ArticleID']]['CategoryName'][] = $b['CategoryName'];
    }
    return $a;
});

var_dump($array);

Output

array
  2 => 
    array
      'CategoryID' => int 3
      'CategoryName' => 
        array
          0 => string 'Test Category' (length=13)
          1 => string 'Test Images' (length=11)
          2 => string 'Test B' (length=6)
      'Parent' => int 0
      'Thumb' => int 0
      'sort' => int 8
      'ArticleID' => int 2
      'ArticleCatgories' => string '9,4,3' (length=5)
      'ArticleTitle' => string 'vxcvxcvx' (length=8)
      'ArticleBody' => string 'xcvxcvxcvxcv' (length=12)
      'InGroup' => int 0
      'GroupID' => int 0
      'Published' => int 1
      'PublishTime' => null
      'TermID' => int 11
      'TermSlug' => string 'xcvxcvxcv' (length=9)
      'RelatedID' => int 2
      'TermType' => string 'article' (length=7)
  3 => 
    array
      'CategoryID' => int 4
      'CategoryName' => 
        array
          0 => string 'Test Image' (length=10)
          1 => string 'Test A' (length=6)
      'Parent' => int 0
      'Thumb' => int 0
      'sort' => int 4
      'ArticleID' => int 3
      'ArticleCatgories' => string '9,4,3' (length=5)
      'ArticleTitle' => string 'vxcvxcvx' (length=8)
      'ArticleBody' => string 'xcvxcvxcvxcv' (length=12)
      'InGroup' => int 0
      'GroupID' => int 0
      'Published' => int 1
      'PublishTime' => null
      'TermID' => int 11
      'TermSlug' => string 'xcvxcvxcv' (length=9)
      'RelatedID' => int 2
      'TermType' => string 'article' (length=7)

the array_reduce example work and but it just return the array and my sql query return multi array and multi Article Ids not only 1
@Baba the abuse of the ternary is not necessary 3v4l.org/GKiZ1 ... or at least it is not necessary anymore (I don't know if null used to be the default accumulator back in the day).

Kartik · Accepted Answer · 2012-10-04 02:35:41Z

-1

This is really a quick and dirty way of doing it but this is how it goes:

$orig is the original array posed in the question.

You basically iter the array and get all the categories and add them to $keys. Now assuming that all the other keys and values are same for the original array (except that category of course), you can just pick any element from that array and call it your $final array.

After that, you simply replace the category values with the array of the combined categories.

$orig = array();

$final = array();
$keys = array();

foreach($orig as $i)
{
    $keys[] = $i['CategoryName'];
}

$final = $orig[0];
$final['CategoryName'] = $keys;

edited Oct 4, 2012 at 2:35

answered Oct 4, 2012 at 2:28

Kartik

9,9319 gold badges50 silver badges52 bronze badges

1 Comment

Dr.Neo Over a year ago

this on is return the first result only not showing all results

Collectives™ on Stack Overflow

combine array values in sub array?

3 Answers 3

Comments

2 Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

2 Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related