Old question but the remaining answers are outdated as of C++11 – you can use a ranged based for loop and simply do: std::map<std::string, std::map<std::string, std::string>> mymap; for(auto const &ent1 : mymap) { // ent1.first is the first key for(auto const &ent2 : ent1.second) { // ent2.first is the second key // ent2.second is the … Read more
First of all, there are cases when object construction is a task complex enough to justify its extraction to another class. I believe this point is incorrect. The complexity doesn’t really matter. The relevance is what does. If an object can be constructed in one step (not like in the builder pattern), the constructor is … Read more
Python 2.6+ next(iter(your_list), None) If your_list can be None: next(iter(your_list or []), None) Python 2.4 def get_first(iterable, default=None): if iterable: for item in iterable: return item return default Example: x = get_first(get_first_list()) if x: … y = get_first(get_second_list()) if y: … Another option is to inline the above function: for x in get_first_list() or []: … Read more
Best: min(d, key=d.get) — no reason to interpose a useless lambda indirection layer or extract items or keys! >>> d = {320: 1, 321: 0, 322: 3} >>> min(d, key=d.get) 321
The instance initialiser is just syntactic sugar in this case, right? I don’t see why you need an extra anonymous class just to initialize. And it won’t work if the class being created is final. You can create an immutable map using a static initialiser too: public class Test { private static final Map<Integer, String> … Read more