PHP How to calculate duplicate values in array - php

Question

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!

Answer 1

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)
}
}

Answer 2

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);