Tutorial by Examples: o

Anything that needs to happen with data in an IndexedDB database happens in a transaction. There are a few things to note about transactions that are mentioned in the Remarks section at the bottom of this page. We'll use the database we set up in Opening a database. // Create a new readwrite (sinc...

Create a new project dotnet new -l f# Restore any packages listed in project.json dotnet restore A project.lock.json file should be written out. Execute the program dotnet run The above will compile the code if required. The output of the default project created by dotnet new -l f# con...

Espresso by default has many matchers that help you find views that you need to do some checks or interactions with them. Most important ones can be found in the following cheat sheet: https://google.github.io/android-testing-support-library/docs/espresso/cheatsheet/ Some examples of matchers are...

Activity class takes care of creating a window for you in which you can place your UI with setContentView. There are three setContentView methods: setContentView(int layoutResID) - Set the activity content from a layout resource. setContentView(View view) - Set the activity content to an explic...

There are two Collections.sort() methods: One that takes a List<T> as a parameter where T must implement Comparable and override the compareTo() method that determines sort order. One that takes a List and a Comparator as the arguments, where the Comparator determines the sort order. ...

Instead of adding an observer with a selector, a block can be used: id testObserver = [[NSNotificationCenter defaultCenter] addObserverForName:@"TestNotification" object:nil ...

The 'Golden' method minimizes a unimodal function by narrowing the range in the extreme values import numpy as np from scipy.optimize import _minimize from scipy import special import matplotlib.pyplot as plt x = np.linspace(0, 10, 500) y = special.j0(x) optimize.minimize_scalar(special.j0,...

Brent's method is a more complex algorithm combination of other root-finding algorithms; however, the resulting graph isn't much different from the graph generated from the golden method. import numpy as np import scipy.optimize as opt from scipy import special import matplotlib.pyplot as plt ...

Think this could example could be better but you get the gist import numpy as np from scipy.optimize import _minimize from scipy import special import matplotlib.pyplot as plt from matplotlib import cm from numpy.random import randn x, y = np.mgrid[-2:2:100j, -2:2:100j] plt.pcolor(x, y, op...

Creating a Window with OpenGL context (extension loading through GLEW): #define GLEW_STATIC #include <GL/glew.h> #include <SDL2/SDL.h> int main(int argc, char* argv[]) { SDL_Init(SDL_INIT_VIDEO); /* Initialises Video Subsystem in SDL */ /* Setting up OpenGL version a...

Create User Model # Schema: User(token:string, auth_token:string) class User < ActiveRecord::Base has_secure_token has_secure_token :auth_token end Now when you create a new user a token and auth_token are automatically generated user = User.new user.save user.token # => "p...

POSIX stands for "Portable Operating System Interface" and defines a set of standards to provide compatibility between different computing platforms. The current version of the standard is IEEE 1003.1 2016 and can be accessed from the OpenGroup POSIX specification. Previous versions incl...

$username = 'Hadibut'; $email = '[email protected]'; $variables = compact('username', 'email'); // $variables is now ['username' => 'Hadibut', 'email' => '[email protected]'] This method is often used in frameworks to pass an array of variables between two components.

The entries() method returns a new Array Iterator object that contains the key/value pairs for each index in the array. 6 var letters = ['a','b','c']; for(const[index,element] of letters.entries()){ console.log(index,element); } result 0 "a" 1 "b" 2 "c"...

Images, static data, sounds, etc. are resources in a Playground. If the Project Navigator is hidden, choose View > Navigators > Show Project Navigator (⌘1) There are several ways to add files Drag your resources to the Resources folder or Select the Resources folder and choose File &gt...

You can display an SVG file within an HTML document, by specifying it as a background image in CSS. For example: .element { background-size: 100px 100px; background: url(my_svg_file.svg); height: 100px; width: 100px; } If the dimensions specified in your SVG file are larger ...

The Null-Coalescing operator ?? will return the left-hand side when not null. If it is null, it will return the right-hand side. object foo = null; object bar = new object(); var c = foo ?? bar; //c will be bar since foo was null The ?? operator can be chained which allows the removal of if...

Often times you will have reason to catch when your program is being told to stop by the OS and take some actions to preserve the state, or clean up your application. To accomplish this you can use the os/signal package from the standard library. Below is a simple example of assigning all signals fr...

Databings are essential for working with XAML. The XAML dialect for UWP apps provides a type of binding: the {x:Bind} markup extension. Working with {Binding XXX} and {x:Bind XXX} is mostly equivalent, with the difference that the x:Bind extension works at compile time, which enables better debuggi...

Most of the time you need to import namespaces in your XAML file. How this is done is different for the different XAML variants. For Windows Phone, Silverlight, WPF use the clr-namespace syntax: <Window ... xmlns:internal="clr-namespace:rootnamespace.namespace" xmlns:exte...