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C# allows user-defined types to overload operators by defining static member functions using the operator keyword. The following example illustrates an implementation of the + operator. If we have a Complex class which represents a complex number: public struct Complex { public double Real ...

Double Quotes inside verbatim strings can be escaped by using 2 sequential double quotes "" to represent one double quote " in the resulting string. var str = @"""I don't think so,"" he said."; Console.WriteLine(str); Output: "I don't think s...

// assign string from a string literal string s = "hello"; // assign string from an array of characters char[] chars = new char[] { 'h', 'e', 'l', 'l', 'o' }; string s = new string(chars, 0, chars.Length); // assign string from a char pointer, derived from a string string s; uns...

var tasks = Enumerable.Range(1, 5).Select(n => new Task<int>(() => { Console.WriteLine("I'm task " + n); return n; })).ToArray(); foreach(var task in tasks) task.Start(); Task.WaitAll(tasks); foreach(var task in tasks) Console.WriteLine(task.Result); ...

For null values: Nullable<int> i = null; Or: int? i = null; Or: var i = (int?)null; For non-null values: Nullable<int> i = 0; Or: int? i = 0;

int? i = null; if (i != null) { Console.WriteLine("i is not null"); } else { Console.WriteLine("i is null"); } Which is the same as: if (i.HasValue) { Console.WriteLine("i is not null"); } else { Console.WriteLine("i is null&quot...

Given following nullable int int? i = 10; In case default value is needed, you can assign one using null coalescing operator, GetValueOrDefault method or check if nullable int HasValue before assignment. int j = i ?? 0; int j = i.GetValueOrDefault(0); int j = i.HasValue ? i.Value : 0; The ...

emails.Where(email => email.From == "John")

emails.Select(email => email.Body)

Subscription returns an IDisposable: IDisposable subscription = emails.Subscribe(email => Console.WriteLine("Email from {0} to {1}", email.From, email.To)); When you are ready to unsubscribe, simply dispose the subscription: subscription.Dispose();

emails.Subscribe(email => Console.WriteLine("Email from {0} to {1}", email.From, email.To), cancellationToken);

Given an async method like this: Task<string> GetNameAsync(CancellationToken cancellationToken) Wrap it as an IObservable<string> like this: Observable.FromAsync(cancellationToken => GetNameAsync(cancellationToken))

The nameof operator allows you to get the name of a variable, type or member in string form without hard-coding it as a literal. The operation is evaluated at compile-time, which means that you can rename, using an IDE's rename feature, a referenced identifier and the name string will update with it...

class TrivialClass {} A class consists at a minimum of the class keyword, a name, and a body, which might be empty. You instantiate a class with the new operator. TrivialClass tc = new TrivialClass();

Executors accept a java.lang.Runnable which contains (potentially computationally or otherwise long-running or heavy) code to be run in another Thread. Usage would be: Executor exec = anExecutor; exec.execute(new Runnable() { @Override public void run() { //offloaded work, no need t...

If your computation produces some return value which later is required, a simple Runnable task isn't sufficient. For such cases you can use ExecutorService.submit(Callable<T>) which returns a value after execution completes. The Service will return a Future which you can use to retrieve the r...

A double is a double-precision 64-bit IEEE 754 floating point number. double example = -7162.37; double myDouble = 974.21; double anotherDouble = 658.7; double addedDoubles = myDouble + anotherDouble; // 315.51 double subtractedDoubles = myDouble - anotherDouble; // 1632.91 double scientif...

// Obtain an instance of JavaScript engine ScriptEngineManager manager = new ScriptEngineManager(); ScriptEngine engine = manager.getEngineByName("nashorn"); // Define a global variable engine.put("textToPrint", "Data defined in Java."); // Print the global var...

Classes implementing Iterable<> interface can be used in for loops. This is actually only syntactic sugar for getting an iterator from the object and using it to get all elements sequentially; it makes code clearer, faster to write end less error-prone. public class UsingIterable { pub...

To create your own Iterable as with any interface you just implement the abstract methods in the interface. For Iterable there is only one which is called iterator(). But its return type Iterator is itself an interface with three abstract methods. You can return an iterator associated with some coll...