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Mithil Shah 
Abstract factory pattern is a creational pattern. It provides an interface using which a client can instantiate a group of related Objects. This tutorial explains the Abstract factory pattern using a Car manufacturing algorithm. Example We design a framework that can build cars. We build two types of cars, a Mazda and a Ferrari. The … Read more
What is Factory Method? Factory method is a creational pattern that helps in abstracting the process of object creation. What this means is that the class that uses the object is not necessarily the class that instantiates the object. In fact, the class that uses the object has absolutely no idea about the exact type … Read more
For Beginners in R, here is a 15 page example based tutorial that covers the basics of R. Starting R – Trivial tutorial on how to start R for those just wondering what to do next after downloading R. Assignment Operator – Two important assignment operators in R are <- and = Listing Objects – … Read more
R has some very useful libraries for working with spatial data. In this blog we will look at some of the libraries and demonstrate few basic functionalities. Lets start with reading a shapefile. How to read a shapefile : We will use the maptools package to read the shape file. Along with the maptools package, … Read more
Here’s an easy way to convert a list of Strings to a String containing csv values <pre class=”brush:java”> StringUtils.join(list, ‘,’) </pre> To reverse conversion can be done by – csv to list <pre class=”brush:java”> Arrays.asList(StringUtils.split(rs.getString(“a,b”), “,”)) </pre>
In The previous blog we looked at how to install the StatET plugin that can be used to run R from eclipse. In This tutorial we will look at the various features of the plugin. Creating a New R Project or File. The plugin provides the following options We create a new R Project and … Read more
Many developers, especially the Java developers are quite comfortable using eclipse for development. There is a very useful and powerful plugin called StatET that can enable eclipse to work as in IDE for R. Lets first look at how to install it on Linux(Ubuntu). The plugin is available from the eclipse marketplace. The eclipse update … Read more
In this post we will look at one of the powerful ‘apply’ group of functions in R – rapply. rapply stands for recursive apply, and as the name suggests it is used to apply a function to all elements of a list recursively. We begin by first creating a straightforward list we use the rapply … Read more
systemd has replaced the univ SysV (System V) and BSD init systems in majority of the linux distributions. Centos 7 now has systemd and has changed the way services are handled. This is not a comprehensive tutorial but a simple introduction on how services are added, started, enabled, listed and removed using systemctl. Before we … Read more
awk -F “,” ‘{printf “%3.6f,%3.6f\n”,($1 – 1),$2}’ file.txt This command reads a file called file.txt and then subtracts 1 from the first row. %3.6 is used to format the output columns. The output can be redirected to another file.