Tutorial by Examples: r

You can use Scan or TryScan methods to look for specific messages in the queue and process them regardless of how many messages are before them. Both methods look at the messages in the queue in the order they arrived and will look for a specified message (up until optional timeout). In case there i...

The root process scatters the contents in sendbuf to all processes (including itself) using the MPI_Scatter operation. int rank; int size; int sendcount = 1; int recvcount = sendcount; int sendbuf[3]; int recvbuf; int root = 0; MPI_Comm_size (MPI_COMM_WORLD, &size); if (size != 3) ...

#!/bin/bash deploy=false uglify=false while (( $# > 1 )); do case $1 in --deploy) deploy="$2";; --uglify) uglify="$2";; *) break; esac; shift 2 done $deploy && echo "will deploy... deploy = $deploy" $uglify && echo "will...

Starting from a sequence of static images (for example called frame01.jpg, frame02.jpg and so on) an animated gif can be created using the following command: magick -delay 10 -loop 0 frame*.jpg animation.gif -delay 10 sets the interval between the frames to 0.1 seconds -loop 0 creates a...

So let's say again that you have the following model: public class Person { public int PersonId { get; set; } public string Name { get; set; } } public class Car { public int CarId { get; set; } public string LicensePlate { get; set; } } public class MyDemoContext : DbContext ...

And to finish off, let's briefly look at the case when both sides are optional. By now you should be really bored with these examples :), so I'm not going into the details and play with the idea of having two FK-s and the potential problems and warn you about the dangers of not enforcing these rule...

Basics require('http').globalAgent.maxSockets = 25 // You can change 25 to Infinity or to a different value by experimenting Node.js by default is using maxSockets = Infinity at the same time (since v0.12.0). Until Node v0.12.0, the default was maxSockets = 5 (see v0.11.0). So, after more tha...

""" CannyTrackbar function allows for a better understanding of the mechanisms behind Canny Edge detection algorithm and rapid prototyping. The example includes basic use case. 2 of the trackbars allow for tuning of the Canny function and the other 2 help with understanding h...

In the previous examples a car cannot exist without a person. What if you wanted the person to be optional from the car side? Well, it's kind of easy, knowing how to do one-to-many. Just change the PersonId in Car to be nullable: public class Car { public int CarId { get; set; } public s...

As an example we want to set all string properties of a sample class class TestClass { val readOnlyProperty: String get() = "Read only!" var readWriteString = "asd" var readWriteInt = 23 var readWriteBackedStringProperty: String = "" ...

Extra goals enable to add processing to DCG clauses, for example, conditions that the elements of the list must satisfy. The extra goals are observed between curly braces at the end of a DCG clause. % DCG clause requiring an integer int --> [X], {integer(X)}. Usage: ?- phrase(int, [3]). t...

The extra arguments add results to predicates of a DCG clause, by decorating the derivation tree. For example, it's possible to create a algebraic grammar that computes the value at the end. Given a grammar that supports the operation addition: % Extra arguments are passed between parenthesis afte...

Let's define a grammar enabling us to perform additions, multiplications with the usage of parenthesis. To add more value to this example, we are going to compute the result of the arithmetic expression. Summary of the grammar: expression → times expression → times '+' expression times → elemen...

Step 1 – Install LAMP To start with Laravel, we first need to set up a running LAMP server. If you have already running LAMP stack skip this step else use followings commands to set up lamp on Ubuntu system. Install PHP 5.6 $ sudo apt-get install python-software-properties $ sudo add-apt-reposit...

Suppose we want to know how many users have the same name. Let us create table users as follows: create table users( id int primary key auto_increment, name varchar(8), count int, unique key name(name) ); Now, we just discovered a new user named Joe and would like to take hi...

Suppose we want to know how many users have the same name. Let us create table users as follows: create table users( id serial, name varchar(8) unique, count int ); Now, we just discovered a new user named Joe and would like to take him into account. To achieve that, we need to d...

Install Firebase resource in the the AppScript To do that click on Resources and then on Libraries. Firebase has a unique project library key that need to be installed in the AppScript. Click on Libraries The following pop-up appears. Enter the following project key in the textbox. MYeP8ZEE...

1. To write a simple data to test whether connection is working or not. function myFunction(){ var firebaseUrl = "https://example-app.firebaseio.com/"; var secret = "secret-key"; var base = FirebaseApp.getDatabaseByUrl(firebaseUrl, secret); base.setData("test&quo...

Team Foundation Server (TFS) can be installed in two basic infrastructure ways, Single Server Deployment and Multi-Server Deployment. The difference between these two deployments is where the Application Tier (TFS) and the Data Tier (MS SQL) reside. It is considered best practice to install TFS in...

it is very easy to write an angularJS controller with ES6 if your are familiarized with the Object Oriented Programming : class exampleContoller{ constructor(service1,service2,...serviceN){ let ctrl=this; ctrl.service1=service1; ctrl.se...