mixed *scramble_array(mixed *arr){
    mixed *ret = copy(arr);
    ret = sort_array(ret, (:random(3)-1:) );
    return ret;
}

mixed *distinct_array(mixed *arr) {
    mapping tmp;
    int i, maxi;

    for(i = 0, tmp = allocate_mapping(maxi = sizeof(arr)); i<maxi; i++){
        tmp[arr[i]] = 1;
    }
    return keys(tmp);
}

mixed *singular_array(mixed *arr) {
    return distinct_array(arr);
}

mixed *remove_member(mixed *arr, int i){
    int size;
    mixed ret;
    if(!arr || (size = (sizeof(arr) - 1)) < i) return 0;
    if(!i) ret = arr[1..];
    else if(size == i) ret = arr[0..(size - 1)];
    else {
        ret = arr[0..(i - 1)] + arr[(i + 1)..];
    }
    return ret;
}