Check whether the string is a unix timestamp

Question

I have a string and I need to find out whether it is a unix timestamp or not, how can I do that effectively?

I found this thread via Google, but it doesn\'t come up

Answer 1

    //if anything else than digits inside the string then your string is no timestamp 
    //in which case maybe try to get the timestamp with strtotime

    if(preg_match('/[^\d]/', $str)) {
        $str = strtotime($str);

        if (false === $str) {
            //conversion failed - invalid time - invalid row
            return;
        }
    }