Tutorial by Examples: an

R in LaTex with Knitr and Internal Code Chunks

Knitr is an R package that allows us to intermingle R code with LaTeX code. One way to achieve this is internal code chunks. This apporach is demonstrated below. # r-noweb-file.Rnw \documentclass{article} \begin{document} This is an Rnw file (R noweb). It contains a combination of LateX a...

R Language • R in LaTeX with knitr

Binding an XML namespace to a serializable Java class.

This is an example of a package-info.java file that binds an XML namespace to a serializable Java class. This should be placed in the same package as the Java classes that should be serialized using the namespace. /** * A package containing serializable classes. */ @XmlSchema ( xmlns = ...

Java Language • JAXB

Build and install OpenCV from source

This is a step-by-step guide to installing OpenCV 3 on a Debian-based Linux system from source. The steps should stay the same for other distros, just replace the relevant package manager commands when installing packages for the build. Note: If you don't feel like wasting time building stuff or di...

opencv • Getting started with opencv

D3js with Angular

Using D3js with Angular can open up new fronts of possibilities such as live updation of charts as soon as data is updated. We can encapsulate complete chart functionality within an Angular directive, which makes it easily reusable. index.html >> <!DOCTYPE html> <html ng-app="...

d3.js • Using D3 with other frameworks

RijndaelManaged

Required Namespace: System.Security.Cryptography private class Encryption { private const string SecretKey = "topSecretKeyusedforEncryptions"; private const string SecretIv = "secretVectorHere"; public string Encrypt(string data...

.NET Framework • Encryption / Cryptography

Creating an App

express my-app

express • express-generator

Scaffolding projects in other languages

By default, dotnet new creates C# projects. You can use the -l or --lang flag to scaffold projects in other languages: dotnet new -l f# dotnet restore dotnet run Currently, dotnet new supports C# and F#.

.net-core • .NET Core command line interface

Creating a NuGet package

To create a NuGet package from a project, run this command from a directory that contains project.json: dotnet pack The resulting .nupkg file will be named and versioned according to the properties in project.json. If there are multiple frameworks targeted in the project file, the package will s...

.net-core • .NET Core command line interface

Adding command line scripts to your python package

Command line scripts inside python packages are common. You can organise your package in such a way that when a user installs the package, the script will be available on their path. If you had the greetings package which had the command line script hello_world.py. greetings/ greetings/ ...

Python Language • setup.py

Installation of Python 2.7.x and 3.x

Note: Following instructions are written for Python 2.7 (unless specified): instructions for Python 3.x are similar. WINDOWS First, download the latest version of Python 2.7 from the official Website (https://www.python.org/downloads/). Version is provided as an MSI package. To install it manu...

Python Language • Getting started with Python Language

Mathematical Constants

Pi The following returns the value of PI formatted to 6 decimal places. The actual value is good to DOUBLE; SELECT PI(); -> 3.141593

MySQL • Arithmetic

Raise a number to a power (POW)

To raise a number x to a power y, use either the POW() or POWER() functions SELECT POW(2,2); => 4 SELECT POW(4,2); => 16

MySQL • Arithmetic

Random Numbers (RAND)

Generate a random number To generate a pseudorandom floating point number between 0 and 1, use the RAND() function Suppose you have the following query SELECT i, RAND() FROM t; This will return something like this iRAND()10.619143887068220.9384516830914230.83482678498591 Random Number in a r...

MySQL • Arithmetic

Absolute Value and Sign (ABS, SIGN)

Return the absolute value of a number SELECT ABS(2); -> 2 SELECT ABS(-46); -> 46 The sign of a number compares it to 0. SignResultExample-1n < 0SELECT SIGN(42); -> 10n = 0SELECT SIGN(0); -> 01n > 0SELECT SIGN(-3); -> -1 SELECT SIGN(-423421); -> -1

MySQL • Arithmetic

How to install and run ggplot2

To install and load the current stable version of ggplot2 for your R installation use: # install from CRAN install.packages("ggplot2") To install the development version from github use # install.packages("devtools") devtools::install_github("hadley/ggplot2") ...

ggplot2 • Getting started with ggplot2

Create unconnected socket, try connect to it and check if connection is established

public class ConnectSocketExample { private int HTTP_PORT = 80; /** * example method to create unconnected socket * then connect to it * at end return connected socket * * @param httpHostName - endpoint host name fot socket connection * @throws IOEx...

sockets • Getting started with sockets

Write to socket a simple http get request, and dump response

/** * we reuse a class written in example: * http://stackoverflow.com/documentation/sockets/2876/introduction-to-sockets#t=201607262114505531351 * pleas to familiar with it first to continue with this one **/ public class WriteToSocketExample extends ConnectSocketExample { private ...

sockets • Getting started with sockets

Read an int from the command line

import java.util.Scanner; Scanner s = new Scanner(System.in); int number = s.nextInt(); If you want to read an int from the command line, just use this snippet. First of all, you have to create a Scanner object, that listens to System.in, which is by default the Command Line, when you start ...

Java Language • Scanner

Create an SKScene that Fills the SKView

A simple use case it to create an SKScene that exactly fills the SKView. This avoids the need to consider scaling the view to fit or setting a camera to show a part of the scene. The following code assumes an SKView called skView already exists (e.g. as defined in Create a Full Screen SKView using ...

sprite-kit • SKScene

Create an SKScene that Scales to fit the SKView

An SKScene has a scaleMode parameter that defines how it will change its size to fit within the SKView it is presented into the SKView if it is not the same size and/or shape. There are four options for scaleMode: AspectFit: the scene is scaled (but not stretched) until it fits within the view. ...

sprite-kit • SKScene