Primer on the R Language

Disclaimer: This material is based on my notes during an R course. It also includes content I consider important for starting. The original material may be found in a GITLAB repository.

Introducction and Basic Interface Commands

Clean a session of R: Ctrl + L

Save a script,in Mac OS Command+S; Linux/Windows Ctrl+S

A command may be interrupted using Esc o Ctrl+C You may want to interrupt a command when there is a loop that just won’t finish

Define the workspace (In RStudio you can also use Session > Set Working Directory > Choose directory)

setwd("PATH")
#Insert the path of your workspace

To run a selected line: In Mac, Command+Enter. In Linux or Windows Ctrl+Enter.

Using R for arithmetical calculations

1+100

## [1] 101

The order of arithmetical operations is respected

(3+(5*(2^2)))

## [1] 23

3 + 5 * 2^2

## [1] 23

1/100000

## [1] 1e-05

Exponential notation may be used

3e2

## [1] 300

3e-2

## [1] 0.03

Trigonometrical functions

Trigonometrical functions are incorporated

•          cos(x)

•          sin(x)

•          tan(x)

•          acos(x)

•          asin(x)

•          atan(x)

For default you must use radians

sin(pi/2)

## [1] 1

Logarithms

The function log() is a natural logarithm Be noticed that the number e, is written as exp(1) in the R language

log(exp(1))

## [1] 1

For a logarithm of base ’n’, use logn()

log2(2)

## [1] 1

Rational Operators

•          ‘>’ More than

•          ‘<’ Less than

•          ‘<=’ Less or equal than

•          ‘>=’ More or equal than

•          ‘==’ Equal

•          ‘!=’ Different

4 != 4

## [1] FALSE

Logical Operators

•          ‘!’ Logical negation

•          ‘&’ Logical conjunction by element

•          ‘&&’ Logical conjunction

•          ‘||’ Logical disjunction

Variable Assignation

Use the operator ‘<- o:p="">

x <- span=""> 9 #Assigning 9 to the value of x

x #Check the value of x

## [1] 9

x <- span="">1/3
y <-x span="">+1

Basic rules for variable assignation

a.        They can’t start with numbers or ’_’

b.        There should not be blank spaces within the name

Vectorization

1:10 #Create a vector with all whole numbers from 1 up to 10

##  [1]  1  2  3  4  5  6  7  8  9 10

1+1:10 #Sum 1 to each member of the vector

##  [1]  2  3  4  5  6  7  8  9 10 11

var<- span="">1:10
var*2 #Multiply by 2 every member of the vector

##  [1]  2  4  6  8 10 12 14 16 18 20

Consult the variables created

ls()

Delete elements

rm()

Example:

t=1

rm(t)

Administrating packages

Check for installed packages

installed.packages()

Install package

install.packages()

Update packages

update.packages()

Delete package

remove.packages()

Download package

install.packages()

”Activate” a package

library()

Search for help in R

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help()