It’s a new C++11 feature. It means that you want to use the compiler-generated version of that function, so you don’t need to specify a body. You can also use = delete to specify that you don’t want the compiler to generate that function automatically. With the introduction of move constructors and move assignment operators, … Read more
There is none. Alas, you have to type out the full type name. Edit: 7 years after being posted, type inference for local variables (with var) was added in Java 10. Edit: 6 years after being posted, to collect some of the comments from below: The reason C# has the var keyword is because it’s … Read more
James Gosling created the original JVM with support of goto statements, but then he removed this feature as needless. The main reason goto is unnecessary is that usually it can be replaced with more readable statements (like break/continue) or by extracting a piece of code into a method. Source: James Gosling, Q&A session
Late answering, probably everybody knows about yield now, but some better documentation has come along. Adapting an example from “Javascript’s Future: Generators” by James Long for the official Harmony standard: function * foo(x) { while (true) { x = x * 2; yield x; } } “When you call foo, you get back a Generator … Read more
len(yourdict.keys()) or just len(yourdict) If you like to count unique words in the file, you could just use set and do like len(set(open(yourdictfile).read().split()))
It’s a hint to the compiler that the variable will be heavily used and that you recommend it be kept in a processor register if possible. Most modern compilers do that automatically, and are better at picking them than us humans.
continue is kind of like goto. Are you familiar with break? It’s easier to think about them in contrast: break terminates the loop (jumps to the code below it). continue terminates the rest of the processing of the code within the loop for the current iteration, but continues the loop.
It has two purposes. jackcogdill has given the first one: It’s used for raising your own errors. if something: raise Exception(‘My error!’) The second is to reraise the current exception in an exception handler, so that it can be handled further up the call stack. try: generate_exception() except SomeException as e: if not can_handle(e): raise … Read more
if(!(child is IContainer)) is the only operator to go (there’s no IsNot operator). You can build an extension method that does it: public static bool IsA<T>(this object obj) { return obj is T; } and then use it to: if (!child.IsA<IContainer>()) And you could follow on your theme: public static bool IsNotAFreaking<T>(this object obj) { … Read more
There are two related concepts, both called “keyword arguments“. On the calling side, which is what other commenters have mentioned, you have the ability to specify some function arguments by name. You have to mention them after all of the arguments without names (positional arguments), and there must be default values for any parameters which … Read more