Tutorial by Examples: ed

It is unlikely that someone uses an unsupported version of Django, and at his own risks. If ever someone does, it must be his concern to know if a feature exists in the given version. Considering the above, it is useless to mention specificities of an unsupported version. 1.6 This kind of block i...

It's possible to write directly to the rendered image data using putImageData. By creating new image data then assigning it to the canvas, you will clear the entire screen. var imageData = ctx.createImageData(canvas.width, canvas.height); ctx.putImageData(imageData, 0, 0); Note: putImageData is...

Hi everyone! This is a demo I love running for people that get started with BigQuery. So let's run some simple queries to get you started. Setup You will need a Google Cloud project: Go to http://bigquery.cloud.google.com/. If it tells you to create a project, follow the link to create a proje...

This is a mistake that causes real confusion for Java beginners, at least the first time that they do it. Instead of writing this: if (feeling == HAPPY) System.out.println("Smile"); else System.out.println("Frown"); they accidentally write this: if (feeling == HAP...

Undo Command:Descriptionuu,undoUndo the most recent change5uUndo the five most recent changes (use any number) Please be aware that in Vim, the 'most recent change' varies according to the mode you are in. If you enter Insert Mode (i) and type out an entire paragraph before dropping back to Normal...

2.1 Required keyword arguments were introduced in Ruby 2.1, as an improvement to keyword arguments. To define a keyword argument as required, simply declare the argument without a default value. def say(message:) puts message end say # => ArgumentError: missing keyword: message say ...

A keyword that is part of certain integer type names. When used alone, int is implied, so that signed, signed int, and int are the same type. When combined with char, yields the type signed char, which is a different type from char, even if char is also signed. signed char has a range that inclu...

A type specifier that requests the unsigned version of an integer type. When used alone, int is implied, so unsigned is the same type as unsigned int. The type unsigned char is different from the type char, even if char is unsigned. It can hold integers up to at least 255. unsigned can also be ...

Unlike a parallel for-loop (parfor), which takes the iterations of a loop and distributes them among multiple threads, a single program, multiple data (spmd) statement takes a series of commands and distributes them to all the threads, so that each thread performs the command and stores the results....

Dependencies can be added for specific product flavors in a similar fashion as build configurations. android { ... productFlavors { flavor1 { //... } flavor2 { //... } } } dependencies { flavor1Compile 'com.and...

EntityState.Added can be set in two fully equivalent ways: By setting the state of its entry in the context: context.Entry(entity).State = EntityState.Added; By adding it to a DbSet of the context: context.Entities.Add(entity); When calling SaveChanges, the entity will be inse...

All libraries come with resources that are not necessary useful to your application. For example Google Play Services comes with translations for languages your own application don’t even support. You can configure the build.gradle file to specify which resource you want to keep. For example: de...

Setting the state of an object graph (a collection of related entities) to Added is different than setting a single entity as Added (see this example). In the example, we store planets and their moons: Class model public class Planet { public Planet() { Moons = new HashSet<...

A pointer to member of derived class can be converted to a pointer to member of base class using static_cast. The types pointed to must match. If the operand is a null pointer to member value, the result is also a null pointer to member value. Otherwise, the conversion is only valid if the member ...

C++14 C++14 introduced a standard way of deprecating functions via attributes. [[deprecated]] can be used to indicate that a function is deprecated. [[deprecated("reason")]] allows adding a specific reason which can be shown by the compiler. void function(std::unique_ptr<A> &&a...

Creates a path from a set of points [{x:?,y:?},{x:?,y:?},...,{x:?,y:?}] with rounded corners of radius. If the corner angle is too small to fit the radius or the distance between corners does not allow room the corners radius is reduced to a best fit. Usage Example var triangle = [ { x: 200...

What is .postMessage(), when and why do we use it .postMessage() method is a way to safely allow communication between cross-origin scripts. Normally, two different pages, can only directly communicate with each other using JavaScript when they are under the same origin, even if one of them is emb...

Starting with Java 8, you can use lambda expressions & predicates. Example: Use a lambda expressions & a predicate to get a certain value from a list. In this example every person will be printed out with the fact if they are 18 and older or not. Person Class: public class Person { p...

Perl interpolates variable names: my $name = 'Paul'; print "Hello, $name!\n"; # Hello, Paul! my @char = ('a', 'b', 'c'); print "$char[1]\n"; # b my %map = (a => 125, b => 1080, c => 11); print "$map{a}\n"; # 125 Arrays may be interpolated as a whol...

<html> <head> <title>Getting started</title> <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/ol3/3.17.1/ol.css" type="text/css"> <script src="https://cdnjs.cloudflare.com/ajax/libs/ol3/3.17.1/ol...