Tutorial by Examples: io

Canvas allows you to context.translate, context.rotate and context.scale in order to draw your shape in the position & size you require. Canvas itself uses a transformation matrix to efficiently track transformations. You can change Canvas's matrix with context.transform You can change Canv...

Spark uses lazy evaluation; that means it will not do any work, unless it really has to. That approach allows us to avoid unnecessary memory usage, thus making us able to work with big data. A transformation is lazy evaluated and the actual work happens, when an action occurs. Example: In [1]: li...

You want to combine arrays into one. For example, you have fruits = ['Broccoli', 'Carrots'] spices = ['Thyme', 'Cinnamon'] and you want to combine them into ingredients = ['Broccoli', 'Carrots', 'Thyme', 'Cinnamon'] Method 1 - using .concat ingredients = fruits.concat spices Method 2 -...

Detailed instructions on getting windows-azure-storage set up or installed.

In most object oriented languages, allocating memory for an object and initializing it is an atomic operation: // Both allocates memory and calls the constructor MyClass object = new MyClass(); In Objective-C, these are separate operations. The class methods alloc (and its historic sibling allo...

Use the following piece of code to set the badge number from within your application (suppose someNumber has been declared before): Objective-C [UIApplication sharedApplication].applicationIconBadgeNumber = someNumber; Swift UIApplication.shared.applicationIconBadgeNumber = someNumber In order ...

There's an installation guide for running a JIRA Server under Windows or Linux / Mac ( see Installing JIRA applications) For local testing there's an SDK, which starts a JIRA test instance and can be used to develop JIRA Plugins (see Set up the Atlassian Plugin SDK and Build a Project)

Detailed instructions on getting core-bluetooth set up or installed.

Create index.js as const {app, BrowserWindow, ipcMain} = require('electron') let win = null app.on('ready', () => { win = new BrowserWindow() win.loadURL(`file://${__dirname}/index.html`) win.webContents.openDevTools() win.on('closed', () => { win = null }) }) ipcM...

To install React Router, just run the npm command npm install --save react-router And you're done. This is literally all you have to do to install react router. Please Note : react-router is dependent on react, So make sure you install react as well. To set up: using an ES6 transpiler, like bab...

context.globalCompositeOperation = "destination-over" "destination-over" compositing places new drawing under existing drawings. context.drawImage(rainy,0,0); context.globalCompositeOperation='destination-over'; // sunny UNDER rainy context.drawImage(sunny,0,0);

context.globalCompositeOperation = "destination-out" "destination-out" compositing uses new shapes to erase existing drawings. The new shape is not actually drawn -- it is just used as a "cookie-cutter" to erase existing pixels. context.drawImage(apple,0,0); conte...

context.globalCompositeOperation = "destination-in" "destination-in" compositing clips existing drawings inside a new shape. Note: Any part of the existing drawing that falls outside the new drawing is erased. context.drawImage(picture,0,0); context.globalCompositeOperation...

Custom sounds may be provided for notifications generated by your app. When the system displays an alert for a local notification or badges an app icon, it plays this sound (so long as the user has not disabled notification sounds). The default value is nil which means no sound is played for your n...

class Category(models.Model): name = models.CharField(max_length=20) class Product(models.Model): name = models.CharField(max_length=64) category = models.ForeignKey(Category, on_delete=models.PROTECT) To get the number products for each category: >>> categories = Ca...

Problem By default, Django immediately commits changes to the database. When exceptions occur during a series of commits, this can leave your database in an unwanted state: def create_category(name, products): category = Category.objects.create(name=name) product_api.add_products_to_cate...

It's important to handle exceptions in your service. When developing the service, you can set the WCF to provide more detailed information, adding this tag to configuration file, usually Web.config: <serviceDebug includeExceptionDetailInFaults="true"/> This tag must be placed w...

You can handle exceptions and throw a most friendly message like 'Unavailable service' throwing a FaultException: try { // your service logic here } catch (Exception ex) { // You can do something here, like log the original exception throw new FaultException("There was a pro...

The FaultException can also includes a FaultCode, that is a string data you can use to pass additional information, so the client can be able to distinguish different exceptions: try { // your service logic here } catch (Exception ex) { throw new FaultException("There was a proble...

Example implementation of a prime factorization algorithm. A prime factorization algorithm will find for a given number n a list of primes, such that if you multiply those primes you get n. The below implementation will add -1 to the list of prime factors in case n < 0. Note that there exists no ...