Tutorial by Examples: r

This example is how to turn an image into a Base64 string (i.e. a string you can use directly in a src attribute of an img tag). This example specifically uses the Imagick library (there are others available, such as GD as well). <?php /** * This loads in the file, image.jpg for manipulation....

Though it is an obsoleted part of the XSI standard, many implementations still support multiple expressions with Boolean operators and parenthesis. The (obsolete) operators are listed below with decreasing precedence. ( expression ) expression -a expression expression -o expression Using thes...

Create simple CRUD Operation Using Serverless Framework Install Serverless framework globally npm install serverless -g Create simple Lambda Service serverless create --template aws-nodejs --path myService Go to the myService Directory it should contain serverless.yml handler.js even...

Generators are fast coded and in many cases a slim alternative to heavy iterator-implementations. With the fast implementation comes a little lack of control when a generator should stop generating or if it should generate something else. However this can be achieved with the usage of the send() fu...

In the following example we will be creating a table called Membership using the AWS Java SDK for DynamoDB. The table will consist of items that represent team assignments. The table will be partitioned by TeamID. Each team will have multiple members, identified by the MemberID (as a sort key). AWS...

Patterns can be used to replace part of an input string. The example below replaces the cent symbol with the dollar symbol. var money = "¢¥€£$¥€£¢" let pattern = "¢" do { let regEx = try NSRegularExpression (pattern: pattern, options: []) let nsString = money as NSS...

To match special characters Double Backslash should be used \. becomes \\. Characters you'll have to escape include (){}[]/\+*$>.|^? The below example get three kinds of opening brackets let specials = "(){}[]" let pattern = "(\\(|\\{|\\[)" do { let regEx = try N...

Underscore is an open source functional programming utility library for JavaScript. Underscore provides many useful functions for working with arrays or collections of JavaScript objects, including filtering, sorting and querying. Node.js Make sure you have node and npm installed then type the fol...

Player player; //The player you want to award your achievement with Achievement achievement; //The achievement you want to award your player player.awardAchievement(achievement); //Awarding the achievement Checking if player has achievement: Player player; Achievement achievement...

First, you need to install pry-byebug gem. Run this command: $ gem install pry-byebug Add this line at the top of your .rb file: require 'pry-byebug' Then insert this line wherever you want a breakpoint: binding.pry A hello.rb example: require 'pry-byebug' def hello_world puts &qu...

Place the following code into a file name helloworld.js console.log("Hello World"); Save the file, and execute it through Node.js: node helloworld.js

Prerequisites: Install Firefox Install Selenium IDE addon (https://addons.mozilla.org/fr/firefox/addon/selenium-ide/) Open the plugin. A button displaying a red circle must be shown. If it's pressed, it means you can start your scenario. The plugin is recording everything you do within this F...

Install a Common Lisp implementation on the server. (E.g. sbcl, clisp, etc...) Install quicklisp on the server. Load SWANK with (ql:quickload :swank) Start the server with (swank:create-server). The default port is 4005. [On your local machine] Create a SSH tunnel with ssh -L4005:127.0.0.1:400...

If you are tired of using long commands in bash you can create your own command alias. The best way to do this is to modify (or create if it does not exist) a file called .bash_aliases in your home folder. The general syntax is: alias command_alias='actual_command' where actual_command is the c...

To switch focus to either main document or first frame of the page. You have to use below syntax. webDriver.SwitchTo().DefaultContent();

The module "struct" provides facility to pack python objects as contiguous chunk of bytes or dissemble a chunk of bytes to python structures. The pack function takes a format string and one or more arguments, and returns a binary string. This looks very much like you are formatting a stri...

ASSERT is used in sensitive areas where you want to be absolutely sure, that a variable has a specific value. If the logical condition after ASSERT turns out to be false, an unhandleable exception (ASSERTION_FAILED) is thrown. ASSERT 1 = 1. "No Problem - Program continues ASSERT 1 = 2. &quo...

for ([declaration-or-expression]; [expression2]; [expression3]) { /* body of the loop */ } In a for loop, the loop condition has three expressions, all optional. The first expression, declaration-or-expression, initializes the loop. It is executed exactly once at the beginning of the lo...

Preconditions These instructions suppose you have any type of Linux, Unix, Mac with bash or Git-bash Windows. Windows: Download and install Git-bash for Windows, then execute 'bash' from command line. Other shells than bash are fine too, just replace the activate command below with activate.csh...

Player playerToHide; Player playerToNotSee; playerToNotSee.hide(playerToHide); //playerToHide will no longer be seen by playerToNotSee. If player is already hidden, nothing happens