Tutorial by Examples: p

The ref keyword for callers of methods is now optional when calling into methods supplied by COM interfaces. Given a COM method with the signature void Increment(ref int x); the invocation can now be written as either Increment(0); // no need for "ref" or a place holder variable any m...

A new pseudo-type dynamic is introduced into the C# type system. It is treated as System.Object, but in addition, any member access (method call, field, property, or indexer access, or a delegate invocation) or application of an operator on a value of such type is permitted without any type checking...

XML <Galaxy> <name>Milky Way</name> <CelestialObject name="Earth" type="planet"/> <CelestialObject name="Sun" type="star"/> </Galaxy> XPATH /Galaxy/*[@name] or //*[@name] OUTPUT <CelestialObje...

XML <Galaxy> <name>Milky Way</name> <CelestialObject name="Earth" type="planet"/> <CelestialObject name="Sun" type="star"/> </Galaxy> XPATH /Galaxy/*[@name='Sun'] or //*[@name='Sun'] OUTPUT <C...

The proof tree (also search tree or derivation tree) is a tree that shows the execution of a Prolog program. This tree helps visualise the chronological backtracking process present in Prolog. The root of the tree represents the initial query and branches are created when choice points occur. Every ...

This example uses Parallel.ForEach to calculate the sum of the numbers between 1 and 10000 by using multiple threads. To achieve thread-safety, Interlocked.Add is used to sum the numbers. using System.Threading; int Foo() { int total = 0; var numbers = Enumerable.Range(1, 10000).ToLis...

This example uses Parallel.For to calculate the sum of the numbers between 1 and 10000 by using multiple threads. To achieve thread-safety, Interlocked.Add is used to sum the numbers. using System.Threading; int Foo() { int total = 0; Parallel.For(1, 10001, () => 0, // in...

ctrl + alt + shift + / (cmd + alt + shift + / on MacOS) should show you the following dialog: Clicking on Registry you will get The key you want to enable/disable is editor.skip.copy.and.cut.for.empty.selection Tested on Linux Ubuntu and MacOS.

POST requests are made with the request.post() method. If you need to send a web form request as a POST body, pass in a dictionary with key-value pairs as the data argument; requests will encode these to a application/x-www-form-urlencoded mimetype body: r = requests.post('https://github.com/', d...

To POST a JSON body, pass in a Python data structure to the json argument; here a dictionary is posted but anything that can be encoded to JSON will do: import requests # Create a dictionary to be sent. json_data = {'foo': ['bar', 'baz'], 'spam': True, 'eggs': 5.5} # Send the data. response...

When a response contains valid JSON, just use the .json() method on the Response object to get the decoded result: response = requests.get('http://example.com/') decoded_result = response.json() However, this does not fail gracefully; it will raise a JSONDecodeError if the response object is no...

Docker volumes are not automatically removed when a container is stopped. To remove associated volumes when you stop a container: docker rm -v <container id or name> If the -v flag is not specified, the volume remains on-disk as a 'dangling volume'. To delete all dangling volumes: docker ...

Booleans and other values When dealing with lua it is important to differentiate between the boolean values true and false and values that evaluate to true or false. There are only two values in lua that evaluate to false: nil and false, while everything else, including the numerical 0 evaluate to...

Declaration A common misunderstanding, especially beginners, have is read-only property is the one marked with readonly keyword. That's not correct and in fact following is a compile time error: public readonly string SomeProp { get; set; } A property is read-only when it only has a getter. pu...

K&R void* is a catch all type for pointers to object types. An example of this in use is with the malloc function, which is declared as void* malloc(size_t); The pointer-to-void return type means that it is possible to assign the return value from malloc to a pointer to any other type of ob...

Conditional expressions can be done with ~[ and ~]. The clauses of the expression are separated using ~;. By default, ~[ takes an integer from the argument list, and picks the corresponding clause. The clauses start at zero. (format t "~@{~[First clause~;Second clause~;Third clause~;Fourth cl...

Like many Java objects, all String instances are created on the heap, even literals. When the JVM finds a String literal that has no equivalent reference in the heap, the JVM creates a corresponding String instance on the heap and it also stores a reference to the newly created String instance in th...

With Clipping and Masking you can make some specified parts of elements transparent or opaque. Both can be applied to any HTML element. Clipping Clips are vector paths. Outside of this path the element will be transparent, inside it's opaque. Therefore you can define a clip-path property on elemen...

+ dictionaryWithCapacity: Creates and returns a mutable dictionary, initially giving it enough allocated memory to hold a given number of entries. NSMutableDictionary *dict = [NSMutableDictionary dictionaryWithCapacity:1]; NSLog(@"%@",dict); - init Initializes a newly allocated mut...

NetLogo is available for Windows, Mac, and Linux machines, downloadable from the project homepage. Windows Installer: NetLogo runs on Windows 10, Windows 8, Windows 7 and Vista. NetLogo 5.2.1 was the last version to support Windows XP and Windows 2000. Mac: Mac OS X 10.8.3 or newer is requ...