Echo only the duplicate values of array_count_values result php - php

Question

After both myself and a friend searching for hours upon end, and trying numerous things we are unable to find out how to echo only the duplicate values of array_count_values result. I will break it down:
We have numerous select boxes, which build the array when sent via GET, for example:
<div class="form-group col-sm-2 mb-sm">
<select name="select[]" class="form-control">
<option value="" disabled="" selected="">Select</option>
<option value="optionOne">Option 1</option>
<option value="optionTwo">Option 2</option>
</select>
</div>
<div class="form-group col-sm-2 mb-sm">
<select name="select[]" class="form-control">
<option value="" disabled="" selected="">Select</option>
<option value="optionOne">Option 1</option>
<option value="optionTwo">Option 2</option>
</select>
</div>
<div class="form-group col-sm-2 mb-sm">
<select name="select[]" class="form-control">
<option value="" disabled="" selected="">Select</option>
<option value="optionOne">Option 1</option>
<option value="optionTwo">Option 2</option>
</select>
</div>
We are then doing the following:
if (max(array_count_values($_GET['select'])) == 2) {
$twoSelected = '2 of the selections are the same, which were (DUPLICATE SELECTION HERE)';
}
We have tried a foreach loop, but can't seem to get it to work.
Any help will be very much appreciated.
Kind Regards

Answer 1

Try this one
$array = array("test", "hello", "test", "world", "hello");
$duplicatedValuesArray = array_keys(array_filter(array_count_values($array), function($v) {
return $v > 1;
}));
echo implode(', ',$duplicatedValuesArray);

Answer 2

I think below code is helpful for you to get duplicate value.
$array = array(1=>'12334',2=>'123345',3 =>'Helloo' ,4=>'hello', 5=>'helloo');
// Convert every array value to uppercase, and remove all duplicate values
$notdublicates = array_unique(array_map("strtoupper", $array));
// The difference in the original array $array, and the $notdublicates array
// will be the duplicate values
$getduplicates = array_diff($array, $notdublicates);
print_r($getduplicates);