Question

Hi,
How can we find the count of duplicate elements in a multidimensional array ?

I have an array like this

Array
(
    [0] => Array
        (
            [lid] => 192
            [lname] => sdsss
        )

    [1] => Array
        (
            [lid] => 202
            [lname] =>  testing
        )

    [2] => Array
        (
            [lid] => 192
            [lname] => sdsss
        )

    [3] => Array
        (
            [lid] => 202
            [lname] =>  testing
        )

)

How to find the count of each elements ?

i.e, count of entries with id 192,202 etc

Answer 1

You can adopt this trick; map each item of the array (which is an array itself) to its respective ['lid'] member and then use array_count_value() to do the counting for you.

array_count_values(array_map(function($item) {
    return $item['lid'];
}, $arr);

Plus, it’s a one-liner, thus adding to elite hacker status.

Update

Since 5.5 you can shorten it to:

array_count_values(array_column($arr, 'lid'));