Tutorial by Examples: r

Joseph Fourier showed that any periodic wave can be represented by a sum of simple sine waves. This sum is called the Fourier Series. The Fourier Series only holds while the system is linear. If there is, eg, some overflow effect (a threshold where the output remains the same no matter how much inpu...

using System; using System.Threading; using System.Threading.Tasks; class Program { static void Main( string[] args ) { object sync = new object(); int sum = 0; Parallel.For( 1, 1000, ( i ) => { lock( sync ) sum = sum + i; // lock is necessa...

Using the Library Database, we try to find the last book added to the database for each author. For this simple example we assume an always incrementing Id for each record added. SELECT MostRecentBook.Name, MostRecentBook.Title FROM ( SELECT Authors.Name, Books.Title, ...

As of Qt 5.1 and later you can use QQmlApplicationEngine instead of QQuickView to load and render a QML script. With QQmlApplicationEngine you do need to use a QML Window type as your root element. You can obtain the root context from the engine where you can then add global properties to the cont...

Creating a ServiceHost programmatically (without config file) in its most basic form: namespace ConsoleHost { class ConsoleHost { ServiceHost mHost; public Console() { mHost = new ServiceHost(typeof(Example), new Uri("net.tcp://localhost:9000/Example")); ...

A Cython pyx file needs to be translated to C code (cythonized) and compiled before it can be used from Python. A common approach is to create an extension module which is then imported in a Python program. Code For this example we create three files: hello.pyx contains the Cython code. test.p...

>>> df ID Year Jan_salary Feb_salary Mar_salary 0 1 2016 4500 4200 4700 1 2 2016 3800 3600 4400 2 3 2016 5500 5200 5300 >>> melted_df = pd.melt(df,id_vars=['ID','Year'], v...

abstract class Machine { constructor(public manufacturer: string) { } // An abstract class can define methods of it's own, or... summary(): string { return `${this.manufacturer} makes this machine.`; } // Require inheriting classes to implement methods ...

Example for adding a document: $document = [ 'name' => 'John', 'active' => true, 'info' => ['genre' => 'male', 'age' => 30] ]; $bulk = new \MongoDB\Driver\BulkWrite; $_id1 = $bulk->insert($document); $result = $manager->executeBulkWrite('database_name.collect...

Navigation Drawers are used to navigate to top-level destinations in an app. Make sure that you have added design support library in your build.gradle file under dependencies: dependencies { // ... compile 'com.android.support:design:25.3.1' } Next, add the DrawerLayout and Navigati...

auto can also cause problems where expression templates come into play: auto mult(int c) { return c * std::valarray<int>{1}; } auto v = mult(3); std::cout << v[0]; // some value that could be, but almost certainly is not, 3. The reason is that operator* on valarray gives yo...

Introduction Unity has a few 'specially named' folders that allows for a variety of uses. One of these folders is called 'Resources' The 'Resources' folder is one of only TWO ways of loading assets at runtime in Unity (The other being AssetBundles (Unity Docs) The 'Resources' folder can reside an...

Using range-base loops, you can loop over a sub-part of a given container or other range by generating a proxy object that qualifies for range-based for loops. template<class Iterator, class Sentinel=Iterator> struct range_t { Iterator b; Sentinel e; Iterator begin() const { return ...

Given a local directory with the following contents: └── dir1 ├── subdir1 └── subdir2 We want to create the same subdir1, subdir2 under a new directory dir2, which does not exist yet. import os os.makedirs("./dir2/subdir1") os.makedirs("./dir2/subdir2") R...

select * from sys.dm_resource_governor_workload_groups select * from sys.dm_resource_governor_resource_pools

First create a resource pool besides the default one CREATE RESOURCE POOL [PoolAdhoc] WITH(min_cpu_percent=0, max_cpu_percent=50, min_memory_percent=0, max_memory_percent=50) GO Create the worload group for the pool CREATE WORKLOAD GROUP [AdhocMedium] WITH(importa...

Detailed instructions on getting mule set up or installed. Before going to start with mule we have to insure that java home is set. Mule CE runtime don't need installation. We have to just unzip the downloaded file and go to bin directory of mule runtime. In MS windows Operating system we have...

Sometimes specific instances of data should be used. Recreation is not desired and referencing static data would have a code smell. It is possible to specify a XmlAdapter instance the Unmarshaller should use, which allows the user to use XmlAdapters with no zero-arg constructor and/or pass data to ...

Using the Employees Table, below is an example to return the Id, FName and LName columns in (ascending) LName order: SELECT Id, FName, LName FROM Employees ORDER BY LName Returns: IdFNameLName2JohnJohnson1JamesSmith4JohnathonSmith3MichaelWilliams To sort in descending order add the DESC keywo...

Multiple fields can be specified for the ORDER BY clause, in either ASCending or DESCending order. For example, using the http://stackoverflow.com/documentation/sql/280/example-databases/1207/item-sales-table#t=201607211314066434211 table, we can return a query that sorts by SaleDate in ascending o...