Tutorials in ML, AWS, R and Java
Concept On a unix environment it is possible for a threaded java application to call a single RServe instance. For each new connection RServe forks a new process. Each new connection has its own working directory. The working directory is retained if it is non empty, even when the connection is closed. Example Program The … Read more
Concept There are two ways to source R script file in RServe Java program. The first way is to directly source it in the java code. The only disadvantage of this method is that each connection would need to do this. As an example consider the following R code # http://rosettacode.org/wiki/Palindrome_detection#R ############################################################################### palindrome false } … Read more
Setup The steps to install and start RServe are shown in the previous tutorial. This tutorial explains how to create a java program that can talk to R using RServe on a linux platform. The steps to set up are. Lets assume for this tutorial that the working directory in linux where you want to … Read more
Related Tutorials First Sample Program Introduction RServe is an R package that allows other applications to talk to R using TCP/IP. It creates a socket server to which other applications can connect. RServe provides client implementation for common languages such as C/C++, Java and PHP. In this series of tutorials we will look at how … Read more
In this tutorial we will look at Reshape R package, reshape2, melt and cast functions. Reshape R package – Introduction and concepts In this tutorial on data frame we saw the reshape function that can be used to convert multiple columns of a dataframe to multiple rows. In the current tutorial we look at the … Read more
In the previous tutorial we looked at printing R objects using the print and cat functions. In this tutorial we look at Pretty printing in R using the Format function.. If R encounters a custom object then it calls the toString() generic method of that object. The sprintF method is a wrapper over C’s sprintf … Read more
In this tutorial we look at functions to print values on R console or file.. The values are normally printed on the console since that is the default sink, but you can specify that the output be sent to a file by opening up a sink to the file. we will see an example of … Read more
In this tutorial we look at how to write functions in R. What are functions? Functions are user defined pieces of code that perform a desired operation on given input(s) and return the output back to the user. The main characteristics of functions are: They contain lines of code enclosed within a body. The variable … Read more
In the previous tutorial we looked at the apply group of functions. In this example we look at mapply and by functions.
In the previous tutorial we saw the different control structures in R. In this tutorial we will look at the following R functions – apply, lapply, sapply, tapply, simplify2array apply The apply function can be used apply a function over specific elements of an array (or matrix). The result is a vector, list or another array. Lets … Read more