Sameer Mathur
R can be used as a calculator. The basic arithmetic operators are:
+ (addition)- (subtraction)* (multiplication)/ (division)^ (exponentiation)# addition
5 + 8
[1] 13
# substraction
8 - 7
[1] 1
# multiplication
5 * 3
[1] 15
# divison
15/5
[1] 3
# exponentiation
4^2
[1] 16
# returns the remainder of the division of 9/2
9 %% 2
[1] 1
Note that, in R, '#' is used for adding comments to explain what the R code is about.
2a. Logarithms and Exponentials
# logarithms base 2 of x=10
log2(10)
[1] 3.321928
# logaritms base 10 of x=10
log10(10)
[1] 1
# Exponential of x=10
exp(10)
[1] 22026.47
2b. Trigonometric functions
# cosine of x=60
cos(60)
[1] -0.952413
# sine of x=60
sin(60)
[1] -0.3048106
# tangent of x=60
tan(60)
[1] 0.3200404
2c. Other mathematical functions
# absolute value of x=-5
abs(-5)
[1] 5
# square root of x=16
sqrt(16)
[1] 4
A variable can be used to store a value. For example, the R code below will store the price in a variable, say “price”:
# price = 7
price <- 7
# or use this
price = 7
Note that, it's possible to use <- or = for variable assignments.
Note that, R is case-sensitive. This means that Price is different from price.
To print the value of the created object, just type its name:
price
[1] 7
# or use the function print()
print(price)
[1] 7
R saves the object price (also known as a variable) in memory.
It's possible to make some operations with it.
# multiply Price by 3
3 * price
[1] 21
You can change the value of the object:
# change the value
price <- 5
# print again
price
[1] 5
The following R code creates two variables holding the width and the height of a rectangle. These two variables will be used to compute the area of the rectangle.
# height of a rectangle
height <- 10
# width of a rectangle
width <- 5
# area of rectangle
area <- height*width
area
[1] 50