R Programming basics

Quick notes on R Datatypes typeof(x) or class(x)– both returns the data type of variable. however, typeof(x) is tend to be more specific x>>Numeric print(typeof(x)) >>>double length(x)– returns the length of a vector (list) or other objects: 1, or any other positive integer number. print(x)– prints the value of x in console R Objects 1.Vector: one-dimensional array containing elements of the same data type. apple >>red, green, yellow 2.List: ordered collection of elements that can be of different data types. list1 >> [,1] [,2] [,3] [1,] "a" "a" "b" [2,] "c" "b" "a" 4.Array: a multi-dimensional data structure where all elements must be of the same data type. a > gender height weight Age 1 Male 152.0 81 42 2 Male 171.5 93 38 3 Female 165.0 78 26 Operators 1.+: adds two vectors. v [1] 10.0 8.5 10.0 2.-: Subtracts second vector from the first v [1] -6.0 2.5 2.0 3.*****: Multiplies both vectors v [1] 16.0 16.5 24.0 4./: Divide the first vector with the second v [1] 0.250000 1.833333 1.500000 5.%%: Give the remainder of the first vector with the second v [1] 2.0 2.5 2.0 6.%/%: The result of division of first vector with second (quotient) v [1] 0 1 1 7.^: The first vector raised to the power of second vector v [1] 256.000 166.375 1296.000 Relational Operators 1.>: Checks if each element of the first vector is greater than the corresponding element of the second vector v >[1] FALSE TRUE FALSE FALSE 2.[1] "truth is found the second time" For Loop A For loop is a repetition control structure that allows you to efficiently write a loop that needs to execute a specific number of times. a=c(1:5) for ( i in a) { print(i) } >> 1 2 3 4 5 While Loop The While loop executes the same code again and again until a stop condition is met. v ="Hello, while loop" cnt = 2 while (cnt < 7) { print(v) cnt = cnt + 1 } >> [1] "Hello, while loop" [1] "Hello, while loop" [1] "Hello, while loop" [1] "Hello, while loop" [1] "Hello, while loop" Next: to skip the current iteration of a loop without terminating it. Break: the loop is immediately terminated

Apr 18, 2025 - 03:17

Quick notes on R

Datatypes

typeof(x) or class(x)– both returns the data type of variable. however, typeof(x) is tend to be more specific

x<-23.5
print(class(x))
>>>Numeric

print(typeof(x))
>>>double

length(x)– returns the length of a vector (list) or other objects: 1, or any other positive integer number.

print(x)– prints the value of x in console

R Objects

1.Vector: one-dimensional array containing elements of the same data type.

apple <- c('red','green',"yellow") #all character data types 
print(apple)

>>>red, green, yellow

2.List: ordered collection of elements that can be of different data types.

list1 <- list(c(2,5,3),21.3,5L) #contains vector, numeric, integer
print(list1)

3.Matrix: a two-dimensional array where all elements must be of the same data type.

M = matrix( c('a','a','b','c','b','a'), nrow = 2, ncol = 3, byrow = TRUE) print(M)
>>>
     [,1] [,2] [,3]
[1,] "a"  "a"  "b" 
[2,] "c"  "b"  "a"

4.Array: a multi-dimensional data structure where all elements must be of the same data type.

a <- array(c('green','yellow'),dim = c(3,3,2)) 
print(a)

     [,1]     [,2]     [,3]    
[1,] "green"  "yellow" "green" 
[2,] "yellow" "green"  "yellow"
[3,] "green"  "yellow" "green" 

, , 2

     [,1]     [,2]     [,3]    
[1,] "yellow" "green"  "yellow"
[2,] "green"  "yellow" "green" 
[3,] "yellow" "green"  "yellow"

5.Data Frame: a two-dimensional, table-like structure where each column can hold data of a different type, making it similar to a spreadsheet or a SQL table.

BMI<-data.frame( gender = c("Male", "Male","Female"), 
height = c(152, 171.5, 165), 
weight = c(81,93, 78), 
Age = c(42,38,26) ) 

print(BMI)

>>>
  gender height weight Age
1   Male  152.0     81  42
2   Male  171.5     93  38
3 Female  165.0     78  26

Operators

1.+: adds two vectors.

v <-c( 2,5.5,6) 
t <-c(8, 3, 4) 
print(v+t)

>>[1] 10.0  8.5 10.0

2.-: Subtracts second vector from the first

v <-c( 2,5.5,6) 
t <-c(8, 3, 4) 
print(v-t)
>>[1] -6.0  2.5  2.0

3.*****: Multiplies both vectors

v <-c( 2,5.5,6) 
t <-c(8, 3, 4) 
print(v*t)
>>[1] 16.0 16.5 24.0

4./: Divide the first vector with the second

v <-c( 2,5.5,6) 
t <-c(8, 3, 4) 
print(v/t)
>>[1] 0.250000 1.833333 1.500000

5.%%: Give the remainder of the first vector with the second

v <-c( 2,5.5,6) 
t <-c(8, 3, 4) 
print(v%%t)
>>[1] 2.0 2.5 2.0

6.%/%: The result of division of first vector with second (quotient)

v <-c( 2,5.5,6) 
t <-c(8, 3, 4) 
print(v%/%t)
>>[1] 0 1 1

7.^: The first vector raised to the power of second vector

v <-c( 2,5.5,6) 
t <-c(8, 3, 4) 
print(v^t)
>>[1]  256.000  166.375 1296.000

Relational Operators

1.>: Checks if each element of the first vector is greater than the corresponding element of the second vector

v <-c(2,5.5,6,9) 
t <-c(8,2.5,14,9) 
print(v>t)
>>[1] FALSE  TRUE FALSE FALSE

2.<: Checks if each element of the first vector is less than the corresponding element of the second vector.

v <-c(2,5.5,6,9) 
t <-c(8,2.5,14,9) 
print(v < t)
>>[1]  TRUE FALSE  TRUE FALSE

3.==: Checks if each element of the first vector is equal to the corresponding element of the second vector.

v <-c(2,5.5,6,9) 
t <-c(8,2.5,14,9) 
print(v == t)
>>[1] FALSE FALSE FALSE  TRUE

4.<=: Checks if each element of the first vector is less than or equal to the corresponding element of the second vector.

v <-c(2,5.5,6,9) 
t <-c(8,2.5,14,9) 
print(v<=t)
>>[1]  TRUE FALSE  TRUE  TRUE

5.!=: Checks if each element of the first vector is unequal to the corresponding element of the second vector.

v <-c(2,5.5,6,9) 
t <-c(8,2.5,14,9) 
print(v!=t)
>>[1]  TRUE  TRUE  TRUE FALSE

Miscellaneous Operators

1.:: Colon operator. It creates the series of numbers in sequence for a vector.

v <-1:8 
print(v)
>>[1] 1 2 3 4 5 6 7 8

2.%in%: This operator is used to identify if an element belongs to a vector.

v1 <-8 
v2 <-12 
t <-1:10 
print(v1 %in% t) 
print(v2 %in% t)
>>[1] TRUE
[1] FALSE

%*%: This operator is used to multiply a matrix with its transpose.

M = matrix( c(2,6,5,1,10,4), nrow= 2,ncol = 3,byrow = TRUE) 
Q = M %*% t(M) 
print(Q)
>>
     [,1] [,2]
[1,]   65   82
[2,]   82  117

Condition

x <- c("what","is","truth") 
if("Truth" %in% x) {
 print("Truth is found the first time") 
} else if ("truth" %in% x) {
 print("truth is found the second time") 
} else { print("There is no Truth in your code ")
 }
>>[1] "truth is found the second time"

For Loop

A For loop is a repetition control structure that allows you to efficiently write a loop that needs to execute a specific number of times.

a=c(1:5) 
for ( i in a) 
 {
 print(i) 
}
>>
1
2
3
4
5

While Loop

The While loop executes the same code again and again until a stop condition is met.

v ="Hello, while loop" 
cnt = 2 
while (cnt < 7) {
 print(v) 
cnt = cnt + 1 
}
>>
[1] "Hello, while loop"
[1] "Hello, while loop"
[1] "Hello, while loop"
[1] "Hello, while loop"
[1] "Hello, while loop"

Next: to skip the current iteration of a loop without terminating it.

Break: the loop is immediately terminated