Tutorial by Examples: sin

Composer tracks which versions of packages you have installed in a file called composer.lock, which is intended to be committed to version control, so that when the project is cloned in the future, simply running composer install will download and install all the project's dependencies. Composer de...

public class Singleton { private readonly static Singleton instance = new Singleton(); private Singleton() { } public static Singleton Instance => instance; } This implementation is thread-safe because in this case instance object is initialized in the static constructor. The ...

This thread-safe version of a singleton was necessary in the early versions of .NET where static initialization was not guaranteed to be thread-safe. In more modern versions of the framework a statically initialized singleton is usually preferred because it is very easy to make implementation mistak...

int getListOfFriends(size_t size, int friend_indexes[]) { size_t i = 0; for (; i < size; i++) { friend_indexes[i] = i; } } C99C11 /* Type "void" and VLAs ("int friend_indexes[static size]") require C99 at least. In C11 VLAs are optional. */ void getLis...

When in a loop, the loop variable (val) in the following example is a single variable that changes value as it goes over the loop. Therefore one must do the following to actually pass each val of values to the goroutine: for val := range values { go func(val interface{}) { fmt.Println...

If you are using the default bash prompt on Linux, you should see the name of the virtual environment at the start of your prompt. (my-project-env) user@hostname:~$ which python /home/user/my-project-env/bin/python

Now that the routes are set up, we need some way to actually change routes. This example will show how to change routes using the template, but it is possible to change routes in TypeScript. Here is one example (without binding): <a routerLink="/home">Home</a> If the user...

You can create a tuple and use a switch like so: var str: String? = "hi" var x: Int? = 5 switch (str, x) { case (.Some,.Some): print("Both have values") case (.Some, nil): print("String has a value") case (nil, .Some): print("Int has a value&...

Assuming you have a model called Post defined in your models.py file that contains blog posts, and has a date_published field. Step 1: Write the context processor Create (or add to) a file in your app directory called context_processors.py: from myapp.models import Post def recent_blog_posts...

To access entities declared in a module from another program unit (module, procedure or program), the module must be used with the use statement. module shared_data implicit none integer :: iarray(4) = [1, 2, 3, 4] real :: rarray(4) = [1., 2., 3., 4.] end module program test !...

Many C interfaces such as SDL2 have their own deletion functions. This means that you cannot use smart pointers directly: std::unique_ptr<SDL_Surface> a; // won't work, UNSAFE! Instead, you need to define your own deleter. The examples here use the SDL_Surface structure which should be fre...

The expansion of a macro often needs to use symbols that weren't passed as arguments by the user (as names for local variables, for example). One must make sure that such symbols cannot conflict with a symbol that the user is using in the surrounding code. This is usually achieved by using GENSYM, ...

os.access is much better solution to check whether directory exists and it's accesable for reading and writing. import os path = "/home/myFiles/directory1" ## Check if path exists os.access(path, os.F_OK) ## Check if path is Readable os.access(path, os.R_OK) ## Check if path i...

When reading multiple values from a channel, using range is a common pattern: func foo() chan int { ch := make(chan int) go func() { ch <- 1 ch <- 2 ch <- 3 close(ch) }() return ch } func main() { for n := r...

Dim array = New Integer() {1, 2, 3, 4} or Dim array As Int32() = {1, 2, 3, 4}

List<String> data = new ArrayList<>(); data.add("Sydney"); data.add("London"); data.add("New York"); data.add("Amsterdam"); data.add("Mumbai"); data.add("California"); System.out.println(data); List<String> sor...

For instance, a computation involving commands to read and write from the prompt: First we describe the "commands" of our computation as a Functor data type {-# LANGUAGE DeriveFunctor #-} data TeletypeF next = PrintLine String next | ReadLine (String -> next) derivin...

Create an application heroku create your-app-name Deploy to Heroku git push heroku master Open your application in a browser heroku open your-app-name List Heroku commands heroku commands General help heroku help Help for a specific command heroku help <command>

EXPOSE <port> [<port>...] From Docker's documentation: The EXPOSE instruction informs Docker that the container listens on the specified network ports at runtime. EXPOSE does not make the ports of the container accessible to the host. To do that, you must use either the -p flag to ...

function getContentTypes(site_url,name_of_the_library){ var ctx = new SP.ClientContext(site_url); var web = ctx.get_web(); list = web.get_lists().getByTitle(name_of_the_library); // You can include any property of the SP.ContentType object (sp.js), for this example we are just ...