Tutorial by Examples: all

In many languages, new instances of a class are created using a special new keyword. In Ruby, new is also used to create instances of a class, but it isn't a keyword; instead, it's a static/class method, no different from any other static/class method. The definition is roughly this: class MyClass ...

When should I use it When the code inside an inline listener is too big and your method / class becomes ugly and hard to read You want to perform same action in various elements (view) of your app To achieve this you need to create a class implementing one of the listeners in the View API. ...

There are two ways to setup the Apache Flex SDK. You can use the provided Apache Flex SDK Installer, an Adobe AIR application that automates the process (on Windows or OS X/macOS). Or you can install it manually which obviously requires a greater comfort with your platform but provides more flexibi...

Modify your Gemfile to include the Devise gem: gem 'devise' Then update your gems with: $ bundle install Run the installers in your project: $ rails generate devise:install Then create your Devise model (e.g. User) with: $ rails generate devise User you'll need to set up the default ...

class Users::OmniauthCallbacksController < Devise::OmniauthCallbacksController include OmniConcern %w[facebook twitter gplus linkedin].each do |meth| define_method(meth) do create end end end Note: In the part “%w[facebook twitter gplus linkedin]”, you should list ...

devise_for :users, controllers: {omniauth_callbacks: 'users/omniauth_callbacks'}

If you want to use RSpec for a Rails project, you should use the rspec-rails gem, which can generate helpers and spec files for you automatically (for example, when you create models, resources or scaffolds using rails generate). Add rspec-rails to both the :development and :test groups in the Gem...

To create a parallel collection from a sequential collection, call the par method. To create a sequential collection from a parallel collection, call the seq method. This example shows how you turn a regular Vector into a ParVector, and then back again: scala> val vect = (1 to 5).toVector vect:...

Do not use parallel collections when the collection elements must be received in a specific order. Parallel collections perform operations concurrently. That means that all of the work is divided into parts and distributed to different processors. Each processor is unaware of the work being done by...

To improve memory allocation performance, many TensorFlow users often use tcmalloc instead of the default malloc() implementation, as tcmalloc suffers less from fragmentation when allocating and deallocating large objects (such as many tensors). Some memory-intensive TensorFlow programs have been kn...

PyPar is a library that uses the message passing interface (MPI) to provide parallelism in Python. A simple example in PyPar (as seen at https://github.com/daleroberts/pypar) looks like this: import pypar as pp ncpus = pp.size() rank = pp.rank() node = pp.get_processor_name() print 'I am r...

Detailed instructions on getting dropwizard set up or installed.

When using async queries, you can execute multiple queries at the same time, but not on the same context. If the execution time of one query is 10s, the time for the bad example will be 20s, while the time for the good example will be 10s. Bad Example IEnumerable<TResult1> result1; IEnumera...

package main import ( "fmt" "net/http" "os" "text/template" ) var requestTemplate string = ` {{range $i, $url := .URLs}} {{ $url }} {{(status_code $url)}} {{ end }}` type Requests struct { URLs []string } func main() {...

java -jar [Path to client JAR] -s [Server address] install-plugin [Plugin ID] The client JAR must be the CLI JAR file, not the same JAR/WAR that runs Jenkins itself. Unique IDs can be found on a plugins respective page on the Jenkins CLI wiki (https://wiki.jenkins-ci.org/display/JENKINS/Plugins) ...

Ada is a programming language for which there exists multiple compilers. One of these compilers, and perhaps the most used, is GNAT. It is part of the GCC toolchain. It can be installed from several sources: The yearly GPL release done by AdaCore, available for free on libre site. This ver...

You can install Magit from MELPA with: M-x package-install RET magit RET

You might wish to install RStudio after you have installed R. RStudio is a development environment for R that simplifies many programming tasks. Windows only: Visual Studio (starting from version 2015 Update 3) now features a development environment for R called R Tools, that includes a live inter...

When you have a zoomed Image (or other content) you may want to drag around the Image to show all of its content in the zoomed in state. This can be achieved by implementing the PanGestureRecognizer. From code this looks like so: var panGesture = new PanGestureRecognizer(); panGesture.PanUpdated...

In some cases we need to apply functions to a set of ND-arrays. Let's look at this simple example. A(:,:,1) = [1 2; 4 5]; A(:,:,2) = [11 22; 44 55]; B(:,:,1) = [7 8; 1 2]; B(:,:,2) = [77 88; 11 22]; A = ans(:,:,1) = 1 2 4 5 ans(:,:,2) = 11 22 44 55 >&...