Tutorial by Examples: p

Installation or Setup

ReactJS is a JavaScript library contained in a single file react-<version>.js that can be included in any HTML page. People also commonly install the React DOM library react-dom-<version>.js along with the main React file: Basic Inclusion <!DOCTYPE html> <html> <...

React • Getting started with React

Installation or Setup

Knockout is available on most JavaScript platforms, or as a standalone script. Include as a script You can download the script from it's download page, then include it in your page with a standard script tag <script type='text/javascript' src='knockout-3.4.0.js'></script> Using a C...

knockout.js • Getting started with knockout.js

Use anonymous functions with apply

apply is used to evaluate a function (maybe an anonymous one) over the margins of an array or matrix. Let's use the iris dataset to illustrate this idea. The iris dataset has measurements of 150 flowers from 3 species. Let's see how this dataset is structured: > head(iris) Sepal.Length Sep...

R Language • *apply family of functions (functionals)

Enum Polymorphism Pattern

When a method need to accept an "extensible" set of enum values, the programmer can apply polymorphism like on a normal class by creating an interface which will be used anywere where the enums shall be used: public interface ExtensibleEnum { String name(); } This way, any enum t...

Java Language • Enums

Adding the Doctype

The <!DOCTYPE> declaration should always be included at the top of the HTML document, before the <html> tag. 5 See HTML 5 Doctype for details on the HTML 5 Doctype. <!DOCTYPE html> 4.01 See HTML 4.01 Doctypes for details on how these types differ from each other. Stri...

HTML • Doctypes

Manipulating Array Elements

Adding elements: [1, 2, 3] << 4 # => [1, 2, 3, 4] [1, 2, 3].push(4) # => [1, 2, 3, 4] [1, 2, 3].unshift(4) # => [4, 1, 2, 3] [1, 2, 3] << [4, 5] # => [1, 2, 3, [4, 5]] Removing elements: array = [1, 2, 3, 4] array.pop # => 4 array # => [1, 2, 3] ...

Ruby Language • Arrays

Print statement vs. Print function

In Python 2, print is a statement: Python 2.x2.7 print "Hello World" print # print a newline print "No newline", # add trailing comma to remove newline print >>sys.stderr, "Error" # print to stderr print("hello"...

Python Language • Incompatibilities moving from Python 2 to Python 3

Installation and Setup

Prerequisites and Requirements for Magento Community Edition 1.9 Hosting Apache 2.x ( with mod_rewrite ) or Nginx 1.7.x Due to the demands of processing Magento operations, it is recommended that you install Magento on a server with at least 2 GB of RAM. This will ensure that all of the s...

magento • Getting started with magento

Obtaining OpenGL

One of the most common misconceptions about OpenGL is, that it were a library that could be installed from 3rd party sources. This misconception leads to many questions in the form "how to I install OpenGL" or "where to download the OpenGL SDK". This is not how OpenGL finds the ...

opengl • Getting started with opengl

Installation or Setup

Windows If you have Visual Studio (any version including express and community) installed, F# should already be included. Just choose F# as the language when you create a new project. Or see http://fsharp.org/use/windows/ for more options. OS X Xamarin Studio supports F#. Alternately, you could u...

F# • Getting started with F#

Installation/Setup

Downloading: Download Bootstrap directly or clone, etc. from the GitHub repository Download your customized version of Bootstrap from official docs Install with bower: bower install bootstrap Install with npm: npm install bootstrap Install with composer: composer require twbs/bootstrap The...

twitter-bootstrap • Getting started with twitter-bootstrap

Read value of pointer that was freed

Even just reading the value of a pointer that was freed (i.e. without trying to dereference the pointer) is undefined behavior(UB), e.g. char *p = malloc(5); free(p); if (p == NULL) /* NOTE: even without dereferencing, this may have UB */ { } Quoting ISO/IEC 9899:2011, section 6.2.4 §2: ...

C Language • Undefined behavior

Function Arguments, "arguments" object, rest and spread parameters

Functions can take inputs in form of variables that can be used and assigned inside their own scope. The following function takes two numeric values and returns their sum: function addition (argument1, argument2){ return argument1 + argument2; } console.log(addition(2, 3)); // -> 5 ...

JavaScript • Functions

Generic selection based on multiple arguments

If a selection on multiple arguments for a type generic expression is wanted, and all types in question are arithmetic types, an easy way to avoid nested _Generic expressions is to use addition of the parameters in the controlling expression: int max_int(int, int); unsigned max_unsigned(unsigned, ...

C Language • Generic selection

Parallel Stream

Note: Before deciding which Stream to use please have a look at ParallelStream vs Sequential Stream behavior. When you want to perform Stream operations concurrently, you could use either of these ways. List<String> data = Arrays.asList("One", "Two", "Three", &q...

Java Language • Streams

Using FOR XML PATH to concatenate values

The FOR XML PATH can be used for concatenating values into string. The example below concatenates values into a CSV string: DECLARE @DataSource TABLE ( [rowID] TINYINT ,[FirstName] NVARCHAR(32) ); INSERT INTO @DataSource ([rowID], [FirstName]) VALUES (1, 'Alex') ,(2, 'Peter') ...

Microsoft SQL Server • FOR XML PATH

Installation or Setup

Windows PowerShell is included with the Windows Management Framework. Installation and Setup are not required on modern versions of Windows. Updates to PowerShell can be accomplished by installing a newer version of the Windows Management Framework. Other Platforms "Beta" version of P...

PowerShell • Getting started with PowerShell

Build and Install Erlang/OTP on Ubuntu

The following examples show two main methods for installing Erlang/OTP on Ubuntu. Method 1 - Pre-built Binary Package Simply run this command and it will download and install the latest stable Erlang release from Erlang Solutions. $ sudo apt-get install erlang Method 2 - Build and Install from...

Erlang Language • Installation

Installation and Setup

Option 1: Leiningen Requires JDK 6 or newer. The easiest way to get started with Clojure is to download and install Leiningen, the de facto standard tool to manage Clojure projects, then run lein repl to open a REPL. Linux curl https://raw.githubusercontent.com/technomancy/leiningen/stable/bin/l...

clojure • Getting started with clojure

Opening the Visual Basic Editor (VBE)

Step 1: Open a Workbook Step 2 Option A: Press Alt + F11 This is the standard shortcut to open the VBE. Step 2 Option B: Developer Tab --> View Code First, the Developer Tab must be added to the ribbon. Go to File -> Options -> Customize Ribbon, then check the box for developer. ...

excel-vba • Getting started with excel-vba