Tutorial by Examples: u

Benchmarking using microbenchmark

You can use the microbenchmark package to conduct "sub-millisecond accurate timing of expression evaluation". In this example we are comparing the speeds of six equivalent data.table expressions for updating elements in a group, based on a certain condition. More specifically: A data....

R Language • Code profiling

Overview of the basic path drawing commands: lines and curves

================== TODO: Link each of the drawing commands below to their individual examples. I don't know how to do this since the links to the individual examples point towards the "draft" folder. TODO: Add examples for these path "action" commands: stroke(), fill(), clip() ...

html5-canvas • Path (Syntax only)

quadraticCurveTo (a path command)

context.quadraticCurveTo(controlX, controlY, endingX, endingY) Draws a quadratic curve starting at the current pen location to a given ending coordinate. Another given control coordinate determines the shape (curviness) of the curve. <!doctype html> <html> <head> <style...

html5-canvas • Path (Syntax only)

bezierCurveTo (a path command)

context.bezierCurveTo(control1X, control1Y, control2X, control2Y, endingX, endingY) Draws a cubic Bezier curve starting at the current pen location to a given ending coordinate. Another 2 given control coordinates determine the shape (curviness) of the curve. <!doctype html> <html&gt...

html5-canvas • Path (Syntax only)

With NetStatusEvent

package { import flash.events.NetStatusEvent; import flash.net.NetStream; import flash.net.NetConnection; import flash.events.Event; import flash.media.Video; import flash.display.Sprite; public class VideoWithNetStatus extends Sprite { private var video:V...

ActionScript 3 • Working with Video

Installation or Setup

Linux Requirements (r0.16.0) Mandatory As per current Apache-Pig documentation it supports only Unix & Windows operating systems. Hadoop 0.23.X, 1.X or 2.X Java 1.6 or Later versions installed and JAVA_HOME environment variable set to Java installation directory Optional Python 2.7 ...

apache-pig • Getting started with apache-pig

Creating a Future

import scala.concurrent.Future import scala.concurrent.ExecutionContext.Implicits.global object FutureDivider { def divide(a: Int, b: Int): Future[Int] = Future { // Note that this is integer division. a / b } } Quite simply, the divide method creates a Future tha...

Scala Language • Futures

Consuming a Successful Future

The easiest way to consume a successful Future-- or rather, get the value inside the Future-- is to use the map method. Suppose some code calls the divide method of the FutureDivider object from the "Creating a Future" example. What would the code need to look like to get the quotient of...

Scala Language • Futures

Consuming a Failed Future

Sometimes the computation in a Future can create an exception, which will cause the Future to fail. In the "Creating a Future" example, what if the calling code passed 55 and 0 to the divide method? It'd throw an ArithmeticException after trying to divide by zero, of course. How would t...

Scala Language • Futures

Putting the Future Together

The previous examples demonstrated the individual features of a Future, handling success and failure cases. Usually, however, both features are handled much more tersely. Here's the example, written in a neater and more realistic way: object Calculator { def calculateAndReport(a: Int, b: Int...

Scala Language • Futures

FULL JOIN

One type of JOIN that is less known, is the FULL JOIN. (Note: FULL JOIN is not supported by MySQL as per 2016) A FULL OUTER JOIN returns all rows from the left table, and all rows from the right table. If there are rows in the left table that do not have matches in the right table, or if there a...

SQL • JOIN

Recursive JOINs

Recursive joins are often used to obtain parent-child data. In SQL, they are implemented with recursive common table expressions, for example: WITH RECURSIVE MyDescendants AS ( SELECT Name FROM People WHERE Name = 'John Doe' UNION ALL SELECT People.Name FROM Peopl...

SQL • JOIN

ESCAPE statement in the LIKE-query

If you implement a text-search as LIKE-query, you usually do it like this: SELECT * FROM T_Whatever WHERE SomeField LIKE CONCAT('%', @in_SearchText, '%') However, (apart from the fact that you shouldn't necessarely use LIKE when you can use fulltext-search) this creates a problem when someb...

SQL • LIKE operator

Rebuild index

Over the course of time B-Tree indexes may become fragmented because of updating/deleting/inserting data. In SQLServer terminology we can have internal (index page which is half empty ) and external (logical page order doesn't correspond physical order). Rebuilding index is very similar to dropping...

SQL • Indexes

Customize the VM Option

You can override the default vmoptions with your own personal settings by choosing Help > Edit Custom VM Options from the Android Studio toolbar. This will create a local copy which you are free to edit. Alternatively, you can edit the default vmoptions directly using the paths given below. Note...

android-studio • Android Studio optimization

Finding the minimum or maximum element

If your array or array-like object is numeric, that is, if all its elements are numbers, then you can use Math.min.apply or Math.max.apply by passing null as the first argument, and your array as the second. var myArray = [1, 2, 3, 4]; Math.min.apply(null, myArray); // 1 Math.max.apply(null, my...

JavaScript • Arrays

Loading default configuration

To read default configuration properties: package com.example; public class ExampleApplication { private Properties getDefaults() throws IOException { Properties defaults = new Properties(); try (InputStream defaultsStream = ExampleApplication.class.getResou...

Java Language • Resources (on classpath)

Adding a metadata endpoint to your service

SOAP services can publish metadata that describes the methods that may be invoked by clients. Clients can use tools such as Visual Studio to automatically generate code (known as client proxies). The proxies hide the complexity of invoking a service. To invoke a service, one merely invokes a metho...

wcf • Your first service

Custom Tag Helper

You can create your own tag helpers by implementing ITagHelper or deriving from the convenience class TagHelper. The default convention is to target an html tag that matches the name of the helper without the optional TagHelper suffix. For example WidgetTagHelper will target a <widget> ta...

asp.net-core • Tag Helpers

Usage of alert()

The alert() method of the window object displays an alert box with a specified message and an OK or Cancel button. The text of that button depends on the browser and can't be modified. Syntax alert("Hello world!"); // Or, alternatively... window.alert("Hello world!"); Prod...

JavaScript • Modals - Prompts