remove duplicates from comma separated string

Question

Is there a better (faster) solution to remove duplicates from a comma separated string?

public function d($dep) { 
    if (strpos($dep,',') !== false) {
        $nd = explode(',',$dep);
        $oa = array_unique($nd);
        $nx = (count($oa) > 1) ? implode(",",$oa) : $oa[0];
    }
    else {
        $nx = $dep;
    }

    return $nx;
}

Thanks guys.

Answer 1

You could use the uniqueness of array keys:

function d($dep) {
    return implode(',', array_keys(array_flip(explode(',', $dep))));
}

array_flip swaps the key-value association, so the values become the keys and vice versa. This will automatically eliminate duplicates. Its runtime complexity is O(n).

Answer 2

Try just this:

$uniqueDep = implode(',', array_unique(explode(',', $dep)));