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. In this post, we will learn how to use R Language as a Calculator.
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 Language 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.
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