Tutorial by Examples: t

var person = new Person { Address = null; }; var city = person.Address.City; //throws a NullReferenceException var nullableCity = person.Address?.City; //returns the value of null This effect can be chained together: var person = new Person { Address = new Address { ...

You can use Scanner to read all of the text in the input as a String, by using \Z (entire input) as the delimiter. For example, this can be used to read all text in a text file in one line: String content = new Scanner(new File("filename")).useDelimiter("\\Z").next(); System.o...

You can use custom delimiters (regular expressions) with Scanner, with .useDelimiter(","), to determine how the input is read. This works similarly to String.split(...). For example, you can use Scanner to read from a list of comma separated values in a String: Scanner scanner = null; tr...

This is placed in a Windows Forms event handler var nameList = new BindingList<string>(); ComboBox1.DataSource = nameList; for(long i = 0; i < 10000; i++ ) { nameList.AddRange(new [] {"Alice", "Bob", "Carol" }); } This takes a long time to execute,...

BindingList<string> listOfUIItems = new BindingList<string>(); listOfUIItems.Add("Alice"); listOfUIItems.Add("Bob");

Overview In this example 2 clients send information to each other through a server. One client sends the server a number which is relayed to the second client. The second client halves the number and sends it back to the first client through the server. The first client does the same. The server st...

Interfaces can be extremely helpful in many cases. For example, say you had a list of animals and you wanted to loop through the list, each printing the sound they make. {cat, dog, bird} One way to do this would be to use interfaces. This would allow for the same method to be called on all of th...

The JavaScriptSerializer.Deserialize<T>(input) method attempts to deserialize a string of valid JSON into an object of the specified type <T>, using the default mappings natively supported by JavaScriptSerializer. using System.Collections; using System.Web.Script.Serialization; // ....

internal class Sequence{ public string Name; public List<int> Numbers; } // ... string rawJSON = "{\"Name\":\"Fibonacci Sequence\",\"Numbers\":[0, 1, 1, 2, 3, 5, 8, 13]}"; Sequence sequence = JsonConvert.DeserializeObject<Seque...

Optional<String> optionalWithValue = Optional.of("foo"); optionalWithValue.ifPresent(System.out::println);//Prints "foo". Optional<String> emptyOptional = Optional.empty(); emptyOptional.ifPresent(System.out::println);//Does nothing.

DOM stands for Document Object Model. It is an object-oriented representation of structured documents like XML and HTML. Setting the textContent property of an Element is one way to output text on a web page. For example, consider the following HTML tag: <p id="paragraph"></p&g...

A normal function declaration looks like this: function foo(){ } A function defined like this is accessible from anywhere within its context by its name. But sometimes it can be useful to treat function references like object references. For example, you can assign an object to a variable based...

There are many ways to create arrays. The most common are to use array literals, or the Array constructor: var arr = [1, 2, 3, 4]; var arr2 = new Array(1, 2, 3, 4); If the Array constructor is used with no arguments, an empty array is created. var arr3 = new Array(); results in: [] Note...

Spread operator 6 With ES6, you can use spreads to separate individual elements into a comma-separated syntax: let arr = [1, 2, 3, ...[4, 5, 6]]; // [1, 2, 3, 4, 5, 6] // in ES < 6, the operations above are equivalent to arr = [1, 2, 3]; arr.push(4, 5, 6); The spread operator also act...

In JavaScript, functions may be anonymously defined using the "arrow" (=>) syntax, which is sometimes referred to as a lambda expression due to Common Lisp similarities. The simplest form of an arrow function has its arguments on the left side of => and the return value on the right...

PHP can be used to add content to HTML files. While HTML is processed directly by a web browser, PHP scripts are executed by a web server and the resulting HTML is sent to the browser. The following HTML markup contains a PHP statement that will add Hello World! to the output: <!DOCTYPE html&gt...

Start by defining a Foo function that we'll use as a constructor. function Foo (){} By editing Foo.prototype, we can define properties and methods that will be shared by all instances of Foo. Foo.prototype.bar = function() { return 'I am bar'; }; We can then create an instance using the ...

Defining an Anonymous Function When a function is defined, you often give it a name and then invoke it using that name, like so: foo(); function foo(){ // ... } When you define a function this way, the Javascript runtime stores your function in memory and then creates a reference to th...

var xhttp = new XMLHttpRequest(); xhttp.onreadystatechange = function () { if (xhttp.readyState === XMLHttpRequest.DONE && xhttp.status === 200) { //parse the response in xhttp.responseText; } }; xhttp.open("GET", "ajax_info.txt", true); xhttp.send(...

Python is a widely used high-level programming language for general-purpose programming, created by Guido van Rossum and first released in 1991. Python features a dynamic type system and automatic memory management and supports multiple programming paradigms, including object-oriented, imperative, f...