Mithil Shah

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

This tutorial looks at some of the common control structures in R. Control Structures define the flow of the program and decides which path the program takes. This decision is based on the evaluation of a variable. These are the basic types of control structures: Introduction if a variable satisfies a particular condition follow path … Read more

In the previous tutorial we saw an introduction to factors and data frames in R. In this tutorial we look at some more functions that can be used on data frames. Multiple columns into single column – stack() The first function that we look at today is the stack function. It can be used to … Read more

In the earlier tutorials we learnt vectors, list, arrays and matrix. In this tutorial we will look at factors and data frame Factors Factors in R store categorical data. Categorical data has discreet values. For example, a vector of months of births of students in a class contains discreet values or categorical data. Their class … Read more

In the previous tutorial we saw atomic vectors and list. In this tutorial we look at Matrix and Array in R. Array An array is a vector with additional attributes dim which stores the dimension of the array and dimnames which stores the names of the dimensions. Here’s an example: > array(1:8,dim=c(2,2,2)) , , 1 … Read more

The basic data structures in R can be divided in to two types Types of data structures Homogeneous All the elements in the data structure are of same type (string, number, boolean etc) Heterogeneous The elements in the data structure can be of mixed type. Basic Data structures in R Here are the basic data … Read more

In this tutorial we look at how to Source R File from the console. R commands can be run from a file using the source command. create a test file called test.R vi test.R add the following line in the file cat(“Sourcing from R file\n”) Now open R and fire this command (give the absolute … Read more

All entities in R are called objects. They can be arrays, numbers, strings, functions. In this tutorial we look at how to list all objects in R. Get a list of all objects function name : objects() or ls() the objects() or ls() function can be used to get a vector of character strings of … Read more