php: check if an array has duplicates

Question

I\'m sure this is an extremely obvious question, and that there\'s a function that does exactly this, but I can\'t seem to find it. In PHP, I\'d like to know if my array has

Answer 1

Here's my take on this… after some benchmarking, I found this to be the fastest method for this.

function has_duplicates( $array ) {
    return count( array_keys( array_flip( $array ) ) ) !== count( $array );
}

…or depending on circumstances this could be marginally faster.

function has_duplicates( $array ) {
    $array = array_count_values( $array );
    rsort( $array );
    return $array[0] > 1;
}