How Can I Efficiently Count Duplicate Items in an Array in PHP?

Counting Duplicate Items in Arrays Efficiently

In programming, it is often necessary to count the occurrences of duplicate items in an array. One common approach is to use arrays or nested loops to keep track of the counts. However, an alternative solution offers a more concise and efficient method: the array_count_values() function.

To use array_count_values(), simply pass your array as the argument. It will return a new array with the keys as the unique values from the original array and the values as the respective counts.

Consider the following code example:

<code class="php">$array = array(12,43,66,21,56,43,43,78,78,100,43,43,43,21);

$vals = array_count_values($array);

echo 'No. of NON Duplicate Items: '.count($vals).'<br><br>';
print_r($vals);</code>

Output:

No. of NON Duplicate Items: 7
Array
(
    [12] => 1
    [43] => 6
    [66] => 1
    [21] => 2
    [56] => 1
    [78] => 2
    [100] => 1
)

As you can see, array_count_values() provides an easy and elegant solution for counting duplicate items in an array. It returns an array of unique values along with their corresponding counts, eliminating the need for manual loop iterations and array manipulation.

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