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up vote 1 down vote favorite

I would like to calculate duplicate values in my array by "groupid":

Example: 

Array
(
    [0] => Array
        (
            [id] => 1230
            [groupid] => 177
            [activity_group_last] => 1229
            [name] => First name
        )

    [1] => Array
        (
            [id] => 1231
            [groupid] => 177
            [activity_group_last] => 1229
            [name] => Second name
        )

    [2] => Array
        (
            [id] => 1232
            [groupid] => 178
            [activity_group_last] => 1229
            [name] => Other name
        )

)

Output array (2 groupid = 177 and 1 groupid = 178):

Array
(
    [0] => Array
        (
            [id] => 1231
            [groupid] => 177
            [activity_group_last] => 1229
            [name] => Second name
            [count] => 2

        )

    [1] => Array
        (
            [id] => 1232
            [groupid] => 178
            [activity_group_last] => 1229
            [name] => Other name
            [count] => 1
        )
)

Thanks!

share|improve this question
    
Um..calculate? what kind of calculation, and on what fields? Please be more specific –  Shredder Aug 11 '11 at 7:10
    
There seems to be some data-loss in your example: Only 1 id value and 1 name value is kept when the 2 arrays with identical groupids are grouped. Is that on purpose? –  Flambino Aug 11 '11 at 7:14
    
It's right example. Just calculate groupids count and remove duplicate. –  user889349 Aug 11 '11 at 7:22
    
If it happens that your array is populated by a SQL query, please do this from the query, not with some PHP code. –  Vincent Savard Aug 11 '11 at 8:05
    
This is my query: $sql = 'SELECT wall.id, members.groupid, last.activity_group_last, groups.name FROM #__community_wall AS wall, #__community_groups_members AS members, #__mod_table AS last, #__community_groups AS groups WHERE members.memberid ='.intval($uid).' AND members.approved = 1 AND members.groupid = wall.contentid AND wall.post_by !='.intval($uid).' AND wall.type="groups" AND wall.id > last.activity_group_last AND last.userid ='.intval($uid).' AND last.activity_group_last > 0 AND last.activity_group_last_new = "0" AND groups.id = members.groupid ORDER BY wall.id'; –  user889349 Aug 11 '11 at 8:42
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2 Answers

up vote 1 down vote accepted

If $value contains your array, then:

$count = array_count_values(array_map(function($item) {
    return $item['groupid'];
}, $value));
var_dump($count);

$_tmp = $count;
$unique = array_filter($value, function(&$item) use (&$_tmp, $count) {
    if (!--$_tmp[$item['groupid']]) {
        $item['count'] = $count[$item['groupid']];
        return true;
    }
    return false;
});
var_dump($unique);

results in:

array(2) {
  [1]=>
  array(5) {
    ["id"]=>
    int(1231)
    ["groupid"]=>
    int(177)
    ["activity_group_last"]=>
    int(1229)
    ["name"]=>
    string(11) "Second name"
    ["count"]=>
    int(2)
  }
  [2]=>
  array(5) {
    ["id"]=>
    int(1232)
    ["groupid"]=>
    int(178)
    ["activity_group_last"]=>
    int(1229)
    ["name"]=>
    string(10) "Other name"
    ["count"]=>
    int(1)
  }
}
share|improve this answer
    
Great! Thanks... –  user889349 Aug 11 '11 at 7:34
    
+1, but you could add some comments, unless you aspire for the "Most Obscure Code Snippet of the Day" -award ;-) –  nikc.org Aug 11 '11 at 7:35
    
But I need to add: [count] => X to output array –  user889349 Aug 11 '11 at 7:35
    
added "count" of items –  realmfoo Aug 11 '11 at 8:04
    
Yes my friend, you are the rock! –  user889349 Aug 11 '11 at 8:40
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up vote 0 down vote

You can also do this using an iterative function. If your input array is stored in $input and you want the results in $output:

function remove_duplicates($input_array) {
  $output_array = array();            // Create an empty array for output
  foreach($input_array as $input) {   // Loop the input array
    if(array_key_exists($input['groupid'], $output_array)) {
      // We've already seen this groupid at least once
      // Increment count
      $input['count'] = $output_array[$input['groupid']]['count'] + 1;
    } else {
      // First time we've seen this groupid
      // Set count to 1
      $input['count'] = 1;
    }
    // Store data in $output_array, indexed by group_id
    $output_array[$input['groupid']] = $input;
  }
}

// This is your input array
$input = array(array('id'=>1230,'groupid'=>177,'activity_group_last'=>1229,'name'=>'First name'),
           array('id'=>1231,'groupid'=>177,'activity_group_last'=>1229,'name'=>'Second name'),
           array('id'=>1232,'groupid'=>178,'activity_group_last'=>1229,'name'=>'Other name'));
// This will set the output array correctly
$output = remove_duplicates($input);
share|improve this answer
    
Thank you very much! It is great code! –  user889349 Aug 11 '11 at 7:49
    
The is a problem with this function. It output: Array ( [] => Array ( [id] => 1279 [groupid] => 177 [activity_group_last] => 1275 [name] => Name [count] => 4 ) ) But we have other array (input): [2] => Array ( [id] => 1232 [groupid] => 178 [activity_group_last] => 1229 [name] => Other name ) –  user889349 Aug 11 '11 at 8:25
    
The is a problem with this function. It output: Array ( [] => Array ( [id] => 1279 [groupid] => 177 [activity_group_last] => 1275 [name] => Name [count] => 4 ) ) –  user889349 Aug 11 '11 at 8:29
    
Script is updated to set $input to the values you originally provided; in a quick test, it works fine. Can you be more specific with the problem you're seeing? –  Lucas Meyer Aug 12 '11 at 14:40
    
Thank you! Problem solved! –  user889349 Aug 15 '11 at 9:05
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