Tutorial by Examples: in

Installation or Setup

Install .NET Core on macOS 10.11+, after install homebrew: brew update brew install openssl mkdir -p /usr/local/lib ln -s /usr/local/opt/openssl/lib/libcrypto.1.0.0.dylib /usr/local/lib/ ln -s /usr/local/opt/openssl/lib/libssl.1.0.0.dylib /usr/local/lib/ Install .NET Core SDK from https://go...

.net-core • Getting started with .net-core

Naming elements of tuples within discriminated unions

When defining discriminated unions you can name elements of tuple types and use these names during pattern matching. type Shape = | Circle of diameter:int | Rectangle of width:int * height:int let shapeIsTenWide = function | Circle(diameter=10) | Rectangle(width=10) -> t...

F# • Discriminated Unions

Installation for Windows with VirtualBox and SSH support

To use Vagrant on Windows platform you need to install virtualization software and an ssh command-line tool first. This example will use freeware VirtualBox and Cygwin. Install VirtualBox Download the latest VirtualBox version from the official download page and run the downloaded file. Note that ...

vagrant • Getting started with vagrant

Elements inspector

Clicking the Select an element in the page to inspect it button in the upper left corner of the Elements tab in Chrome or Inspector tab in Firefox, available from Developer Tools, and then clicking on a element of the page highlights the element and assigns it to the $0 variable. Elements inspecto...

JavaScript • Debugging

Installing PrimeFaces

PrimeFaces can be used in all web applications based on Java Server Faces (version 2.x) which are run on Servlet Containers (e.g. Wildlfy or Tomcat or GlassFish). There are several ways you can add PrimeFaces to your application. Manually Download the primefaces-{version}.jar and add it to you cl...

primefaces • Getting started with primefaces

Defining a class

A class can be defined using classdef in an .m file with the same name as the class. The file can contain the classdef...end block and local functions for use within class methods. The most general MATLAB class definition has the following structure: classdef (ClassAttribute = expression, ...) Cla...

MATLAB Language • Object-Oriented Programming

Installation or Setup

Setup for Yii 1.1 Step 1 - downloading Yii Download the Yii framework bundle from the Yii website Inside the downloaded bundle there are 3 folders, namely: demos framework requirements demos, as the name suggests contains a number of demo Yii applications. framework contains the Yii framew...

yii • Getting started with yii

Subquery in WHERE clause

Use a subquery to filter the result set. For example this will return all employees with a salary equal to the highest paid employee. SELECT * FROM Employees WHERE Salary = (SELECT MAX(Salary) FROM Employees)

SQL • Subqueries

Subquery in FROM clause

A subquery in a FROM clause acts similarly to a temporary table that is generated during the execution of a query and lost afterwards. SELECT Managers.Id, Employees.Salary FROM ( SELECT Id FROM Employees WHERE ManagerId IS NULL ) AS Managers JOIN Employees ON Managers.Id = Employees.Id ...

SQL • Subqueries

Subquery in SELECT clause

SELECT Id, FName, LName, (SELECT COUNT(*) FROM Cars WHERE Cars.CustomerId = Customers.Id) AS NumberOfCars FROM Customers

SQL • Subqueries

Parsing HTML from a string

PHP implements a DOM Level 2 compliant parser, allowing you to work with HTML using familiar methods like getElementById() or appendChild(). $html = '<html><body><span id="text">Hello, World!</span></body></html>'; $doc = new DOMDocument(); libxml_u...

PHP • Parsing HTML

Using XPath

$html = '<html><body><span class="text">Hello, World!</span></body></html>'; $doc = new DOMDocument(); $doc->loadHTML($html); $xpath = new DOMXPath($doc); $span = $xpath->query("//span[@class='text']")->item(0); echo $span-&...

PHP • Parsing HTML

Reading and writing to a file using ioutil

A simple program that writes "Hello, world!" to test.txt, reads back the data, and prints it out. Demonstrates simple file I/O operations. package main import ( "fmt" "io/ioutil" ) func main() { hello := []byte("Hello, world!") //...

Go • File I/O

Listing all the files and folders in the current directory

package main import ( "fmt" "io/ioutil" ) func main() { files, err := ioutil.ReadDir(".") if err != nil { panic(err) } fmt.Println("Files and folders in the current directory:") for _, fileInfo := range fi...

Go • File I/O

Accessing class members

To access member variables and member functions of an object of a class, the . operator is used: struct SomeStruct { int a; int b; void foo() {} }; SomeStruct var; // Accessing member variable a in var. std::cout << var.a << std::endl; // Assigning member variable b in v...

C++ • Classes/Structures

Creating a pure JSON table

To create a pure JSON table you need to provide a single field with the type JSONB: CREATE TABLE mytable (data JSONB NOT NULL); You should also create a basic index: CREATE INDEX mytable_idx ON mytable USING gin (data jsonb_path_ops); At this point you can insert data in to the table and que...

postgresql • JSON Support

Querying complex JSON documents

Taking a complex JSON document in a table: CREATE TABLE mytable (data JSONB NOT NULL); CREATE INDEX mytable_idx ON mytable USING gin (data jsonb_path_ops); INSERT INTO mytable VALUES($$ { "name": "Alice", "emails": [ "[email protected]", ...

postgresql • JSON Support

Installation of scikit-learn

The current stable version of scikit-learn requires: Python (>= 2.6 or >= 3.3), NumPy (>= 1.6.1), SciPy (>= 0.9). For most installation pip python package manager can install python and all of its dependencies: pip install scikit-learn However for linux systems it is recomm...

scikit-learn • Getting started with scikit-learn

Installation or Setup

The D programming language's standard compiler DMD can run on all major platforms. To install DMD see here. To install by command line you may run the command (found on the D website): curl -fsS https://dlang.org/install.sh | bash -s dmd Package Managers Arch Linux pacman -S dlang Chocolate...

D Language • Getting started with D Language

Formatted strings

Ruby can inject an array of values into a string by replacing any placeholders with the values from the supplied array. "Hello %s, my name is %s!" % ['World', 'br3nt'] # => Hello World, my name is br3nt! The place holders are represented by two %s and the values are supplied by the...

Ruby Language • Strings