R Language Basics

Launching R Console in Windows

In this article, we will learn how to use R as a Calculator. Before using R as a calculator, one needs to launch the R software first. In the Windows Operating system, The R installer will have created an icon for R on the desktop and a Start Menu item. Double-click the R icon to start the R Program; R will open the console, to type R commands.

R Prompt

The greater than sing (>) in the console is the prompt symbol. In this tutorial, we will use the R language as a calculator (we will be Using R for the computation of mathematical expressions), by typing some simple mathematical expressions at the prompt (>). Anything that can be computed on a pocket calculator can also be computed at the R prompt. After entering the expression on the prompt, you have to press the Enter key from the keyboard to execute the command.

Using R as a Calculator

Some examples using R as a calculator are as follows

1 + 2   #add two or more numbers
1 - 2   #Substracts two or more numbers
1 * 2   #multiply two or more numbers
1 / 2   #divides two more more numbers
1 %/% 2 #gives the integer part of the quotient
2 ^ 1   #gives exponentiation
31 %% 7 #gives the remainder after division

These operators also work fine for complex numbers.

Upon pressing the enter key, the result of the expression will appear, prefixed by a number in a square bracket:

1 + 2

# output
[1] 54

The [1] indicates that this is the first result from the command.

Scientific Calculator Type Functions in R

One can also use R as an advanced scientific calculator. Some advanced calculations that are available in scientific calculators can also be easily done in R for example,

sqrt(5)      #Square Root of a number
log(10)      #Natural log of a number
sin(45)      #Trignometric function (sin function)
pi           #pi value 3.141593
exp(2)       #Antilog, e raised to a power
log10(5)     #Log of a number base 10
factorial(5) #Factorial of a number e.g 5!
abs(1/-2)    #Absolute values of a number 
2*pi/360     #Number of radian in one Babylonian degree of a circle

Remember R prints all very large or very small numbers in scientific notation.

Order of Precedence/ Operations

The R language also makes use of parentheses for grouping operations to follow the rules for the order of operations. for example

1 - 2/3   #It first computes 2/3 and then subtracts it from 1
(1-2)/3   #It first computes (1-2) and then divides it by 3

The R Language recognizes certain goofs, like trying to divide by zero, missing values in data, etc.

1/0       # Undefined, R tells it an infinity (Inf)
0/0       # Not a number (NaN) 
"one"/2   # Strings or characters is divided by a number

Further Reading: Computing Descriptive Statistics in R

Online MCQs Computer Science with Answers

The post is about an introduction to R Language. In this introduction to R Language, we will discuss here a short history of R programming language, obtaining R, the installation path of the language, installing R, and R console. Let us start with an introduction to the R language.

Introduction to R Language

R is an open-source (GPL) programming language for statistical computing and graphics, made after S and S-plus language. The S language was developed by AT&T laboratories in the late ’80s. Robert Gentleman and Ross Ihaka started the research project of the statistics department of the University of Auckland in 1995 called R Language.

The R language is currently maintained by the R core development team (an international team of volunteer developers). The (R Project website) is the main site for information about R. From this page information about obtaining the software, accompanying package, and many other sources of documentation (help files) can be obtained.

R provides a wide variety of statistical and graphical techniques such as linear and non-linear modeling, classical statistical tests, time-series analysis, classification, multivariate analysis, etc., as it is an integrated suite of software having facilities for data manipulation, calculation, and graphics display. It includes

• Effective data handling and storage facilities
• Have a suite of operators for calculation on arrays, particularly for matrices
• Have a large, coherent, integrated collection of intermediate tools for data analysis
• Graphical data analysis
• Conditions, loops, user-defined recursive functions, and input-output facilities.

Obtaining R Software

R language Software can be obtained/downloaded from the R Project site the ready-to-run (binaries) files for several operating systems such as Windows, Mac OS X, Linux, Solaris, etc. The source code for R is also available for download and can be compiled for other platforms. R language simplifies many statistical computations as R is a very powerful statistical language with many statistical routines (programming code) developed by people from all over the world and freely available from the R project website as “Packages”. The basic installation of R language contains many powerful sets of tools and it includes some basic packages required for data handling and data analysis.

Many users of R think of R as a statistical system, but it is an environment within which statistical techniques are implemented. The R language can also be extended via packages.

Installing R

For the Windows operating system, the binary version is available from http://cran.r- project.org/bin/windows/base/. “R-4.4.1-win.exe. R-4.4.1” (Race for Your Life) is the latest version of R released on 15 June 2024 by Duncan Murdoch.

After downloading the binary file double-click it, and almost automatic installation of the R system will start although the customized installation option is also available. Follow the instructions during the installation procedure. Once the installation process is complete, you have the R icon on your computer desktop.

The R Console

When R starts, you will see R console windows, where you type commands to get the required results. Note that commands are typed on the R Console command prompt. You can also edit the commands previously typed on the command prompt by using the left, right, up, and down arrow keys, home, end, backspace, insert and delete keys from the keyboard. Command history can be obtained by up and down arrow keys to scroll through recent commands. It is also possible to type commands in a file and then execute the file, using the source function in the R console.

Books on R Programming Language

The following books can be useful for learning the R and S language.

• “Practicing R for Statistical Computing by Aslam, M, and Imdad Ullah, M., Springer, 2023.
• “Psychologie statistique avec R” by Yvonnick Noel. Partique R. Springer, 2013.
• “Instant R: An introduction to R for Statistical Analysis” by Sarah Stowell. Jotunheim Publishing, 2012.
• “Financial Risk Modeling and Portfolio Optimization with R” by Bernhard Pfaff. Wiley, Chichester, UK, 2012.
• “An R Companion to Applied Regression” by John Fox and Sanford Weisberg, Sage Publications, Thousand Oaks, CA, USA, 2nd Edition, 2011,
• “R Graphs Cookbook” by Hrishi Mittal, Packt Publishing, 2011
• “R in Action” by Rob Kabacoff. Manning, 2010.
• “The Statistical Analysis with R Beginners Guide” by John M. Quick. Packt Publishing, 2010.
• “Introducing Monte Carlo Methods with R” by Christian Robert and George Casella. Use R. Springer, 2010.
• “R for SAS and SPSS users” by Robert A. Muenchen. Springer Series in Statistics and Computing. Springer, 2009.

MCQs General Knowledge

This post is about some frequently asked Questions about R Language. The frequently asked questions are about compilers in R, R packages, just in just-in-time compilers, procedural programming in R, and the Recycling rule of vectors. These questions will help you prepare for examinations and interviews.

Questions about R Language

Question: What is a Compiler in R Language?
Answer: A compiler is software that transforms computer code (source code) to another computer language (target language, i.e., object code).

Question: What is a package in R Language?
Answer: The R package is a collection of R functions, compiled code, sample data, and help documentation. The R packages are stored in a directory called “library” in the R environment. The R language also installed a set of packages during installation.

Question: What is JIT?
Answer: JIT standards for “Just in Time” compiler. It is a method to improve the run-time performance of a computer program.

Question: What is procedural Programming in R Language?
Answer: Procedural programming is derived from structured programming and it is based on the concept of procedure call. Procedures are also known as routines, subroutines, or functions. It contains a series of computational steps to be carried out. Any procedure may be called (at any point) during a program’s execution.

Mathematical Operation in R

Question: What is the recycling of elements in a vector?
Answer: When a mathematical operation (such as addition, subtraction, multiplication, division, etc) is performed on two vectors of different lengths (the number of elements in both vectors is different), the element having a shorter length is reused to complete the mathematical operations.

vect1 <- c(4, 1, 4, 5, 6, 9)
vect2 <- c(2, 5)
vect1 * vect2 

###
8, 5, 8, 25, 12, 45

The elements of vect2 are recycled to complete the operation of all elements of vect1.

Question: What is the difference between a data frame and a matrix in R Language?
Answer: In R, the data frame contains heterogeneous data (different columns of the data frame may have different types of variable) while a matrix contains homogeneous data (all the columns of the matrix have the same type of variable). In a matrix, similar data types can be stored while in a data frame, different types of data can be stored.

See Questions about R language Missing Values

MCQs General Knowledge, MCQs in Statistics