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This is the last of the creational patterns. In the earlier tutorials we have seen the factory method, the abstract factory pattern, the builder pattern and the prototype pattern. In this tutorial we will look at the Singleton pattern. The singleton pattern ensures that only once instance of a class is created and the client … Read more
What is the Prototype Design Pattern The prototype design pattern is a method where a new instance of an object is obtained by asking a manager to return the clone of one. In the earlier tutorials we saw how abstract factory pattern can be used to create a family of objects and builder pattern can … Read more
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