Tutorial by Examples: e

The typical example is an abstract shape class, that can then be derived into squares, circles, and other concrete shapes. The parent class: Let's start with the polymorphic class: class Shape { public: virtual ~Shape() = default; virtual double get_surface() const = 0; virtual vo...

Packages are collections of R functions, data, and compiled code in a well-defined format. Public (and private) repositories are used to host collections of R packages. The largest collection of R packages is available from CRAN. Using CRAN A package can be installed from CRAN using following code...

To install package from local source file: install.packages(path_to_source, repos = NULL, type="source") install.packages("~/Downloads/dplyr-master.zip", repos=NULL, type="source") Here, path_to_source is absolute path of local source file. Another command that ...

Here is a full Activity class that places a Marker at the current location, and also moves the camera to the current position. There are a few thing going on in sequence here: Check Location permission Once Location permission is granted, call setMyLocationEnabled(), build the GoogleApiClient, ...

Definition of Decorator as per Wikiepdia: The Decorator pattern can be used to extend (decorate) the functionality of a certain object statically, or in some cases at run-time, independently of other instances of the same class, provided some groundwork is done at design time. Decorator attach add...

Django makes it really easy to add additional data onto requests for use within the view. For example, we can parse out the subdomain on the request's META and attach it as a separate property on the request by using middleware. class SubdomainMiddleware: def process_request(self, request): ...

Inspecting system resource usage is an efficient way to find misbehaving applications. This example is an equivalent of the traditional top command for containers: docker stats To follow the stats of specific containers, list them on the command line: docker stats 7786807d8084 7786807d8085 D...

Inspecting system resource usage is an efficient way to narrow down a problem on a live running application. This example is an equivalent of the traditional ps command for containers. docker top 7786807d8084 To filter of format the output, add ps options on the command line: docker top 7786807...

'Attaching to a container' is the act of starting a terminal session within the context that the container (and any programs therein) is running. This is primarily used for debugging purposes, but may also be needed if specific data needs to be passed to programs running within the container. The a...

Following the logs is the less intrusive way to debug a live running application. This example reproduces the behavior of the traditional tail -f some-application.log on container 7786807d8084. docker logs --follow --tail 10 7786807d8084 This command basically shows the standard output of the co...

When the last parameter of a function is a closure func loadData(id: String, completion:(result: String) -> ()) { // ... completion(result:"This is the result data") } the function can be invoked using the Trailing Closure Syntax loadData("123") { result in ...

In this example, 2.13.2 is the latest version. We install it via bower, specifying the particular version as ember#2.13.2 and including the save flag to persist it to bower.json. As of writing this post the latest version is 2.13.2. From the command line, in the root of your app's directory, run: ...

Since Ember Data is an Ember CLI add-on we can install it just like any other add-on by using ember install. As of writing this post the latest version is 2.13.1. From the command line, in the root of your app's directory, run: ember install [email protected]

Ember CLI is a normal npm package. To update it we have to uninstall it and then install the version we want. As of writing this post the latest version is 2.13.2. From the command line run: npm uninstall -g ember-cli npm cache clean bower cache clean npm install -g [email protected] To verif...

public class Foo { private IBar _iBar; public IBar iBar { set { _iBar = value; } } public void DoStuff() { _iBar.DoSomething(); } } public interface IBar { void DoSomething(); }

public class Foo { private readonly IBar _iBar; public Foo(IBar iBar) { _iBar = iBar; } public void DoStuff() { _bar.DoSomething(); } } public interface IBar { void DoSomething(); }

We will model the process #Load the forecast package library(forecast) #Generate an AR1 process of length n (from Cowpertwait & Meltcalfe) # Set up variables set.seed(1234) n <- 1000 x <- matrix(0,1000,1) w <- rnorm(n) # loop to create x for (t in 2:n) x[t] <- 0.7...

Sometimes you want to do something with the exception you catch (like write to log or print a warning) and let it bubble up to the upper scope to be handled. To do so, you can rethrow any exception you catch: try { ... // some code here } catch (const SomeException& e) { std::cout &l...

Color state lists can be used as colors, but will change depending on the state of the view they are used for. To define one, create a resource file in res/color/foo.xml <?xml version="1.0" encoding="utf-8"?> <selector xmlns:android="http://schemas.android.com/ap...

A type that conforms to the SequenceType protocol can iterate through it's elements within a closure: collection.forEach { print($0) } The same could also be done with a named parameter: collection.forEach { item in print(item) } *Note: Control flow statements (such as break or continu...