[Part 2] - basics of R language

This article will help you understand the basics of R, which is required to start your data analysis learning.

Variables in R

Variables are used to stored information. In R programming, the"<-" operator is used to assign variables. class() function is used to know the datatypes of a variable.

Few examples can be

skill<- "Programming"
age <- 12

# know the data type of variable
class(age)

Data types in R

Like any other programming language, R also has data types. They are

• numeric - Real numbers (e.g. 2, 10.55, 1000)
• integer - integers (2,5,100)
• character - string, characters (e.g "A", "Programming", "12.2")
• logic - boolean values (TRUE, FALSE)
• complex - complex numbers

There are five additional data types defined in R

The function c() is used to create a vector in R

# example of vectors
countries <- c("US", "Canada",  "Brazil",  "France")
age <- c(12, 56, 30, 20, 33, 12)

Operators in R

Like any programming language, R also has many operators. Here is the list.

age <- c(12, 56, 30, 33, 70, 12, 80, 90)

# check age  more than 30
print( age > 30)
[1] FALSE  TRUE FALSE  TRUE  TRUE FALSE  TRUE  TRUE

# check age  less than 70
print( age > 30)
[1]  TRUE  TRUE  TRUE  TRUE FALSE  TRUE FALSE FALSE

# check age is more than 30 and less than 70 
print( age > 30 &  age < 70)
[1] FALSE  TRUE FALSE  TRUE FALSE FALSE FALSE FALSE

Conditions in R

There are many conditional statements in R. Few of them are

• if statement
• if..else
• if..else..if
• ifelse()

if statement

a <- 30
b <- 20
if (a > b) {
  print("A is greater than B")
}

[1] "A is greater than B"

if..else statement

a <- 10
b <- 20
if (a > b) {
  print("A is greater than B")
} else {
  print("B is greater than A")
}

[1] "B is greater than A"

if..else..if statement

a <- 10
b <- 10

if (a > b) {
  print("A is greater than B")
} else if (b > a) {
  print("B is greater than A")
} else {
  print(" A and B are equal")
}

[1] " A and B are equal"

ifelse() statement

ifelse() is a powerful function used for vector bases operations

x <- c(2,3,4,5,6,7)
odd_even =  ifelse(x%%2 == 0, "even", "odd")

> print(x)
[1] 2 3 4 5 6 7
> print(odd_even)
[1] "even" "odd"  "even" "odd"  "even" "odd"

Function in R

Functions are a powerful part of any programming language. The syntax to write a function in R is

functionName <- function(<arguments>){
  # Statement

  return(<returnvalue>)
}

Example: Function to check if a number is even or odd can be

check_odd_even = function(x){
  if (x %% 2 == 0){
    return("EVEN")
  } else {
    return ("ODD")
  }
}

> check_odd_even(4)
[1] "EVEN"
>

Summary of learning

1. Variables in R
2. Data types in R
3. Operators in R
4. Conditions in R
5. Function in R