R Vectors - Create, Access, Modify and Delete a Vector Elements in R

 A Vector in R is basically a set of values of the same basic data type like numeric character etc. A vector in R is created using the c() function that represents a combination of elements.

I have posted basics about R Vectors in the previous post, here we'll learn more about Vector data type.

Creating a Vector in R

In R even a single value is considered as a vector of length 1, We can create a multi-element R Vector using a colon (:) like this

1. #Creating a vector using a colon
2. v <- (1:10)
3. #Print its values
4. print(v)

and output is

1. [1] 1 2 3 4 5 6 7 8 9 10

Create a vector using c() function

1. # A Numeric Vector
2. numeric_vector <- c(10, 20, 30)
3. # A Character Vector
4. character_vector <- c("a", "b", "c")
5. # A Boolean Vector
6. boolean_vector <-c(TRUE,FALSE,TRUE)

now print these vectors

1. > #Print All Vectors
2. > print(numeric_vector)
3. [1] 10 20 30
4. > print(character_vector)
5. [1] "a" "b" "c"
6. > print(boolean_vector)
7. [1] TRUE FALSE TRUE

Accessing Vector Elements in R

Vectors in R works on the concept of the index and to access vector elements value we need to use the index, Indexing in R starts from 1 and here we'll see how to access a vector's value.

1. #Define a Vector
2. v <- c(10,20,30,40,50,60,70,80)
4. #Get element's value using index
5. a <- v[c(1,3,4,6)]
7. #Print values
8. print(a)

and output is

1. [1] 10 30 40 60

We can also use boolean values (TRUE, FALSE) to get elements of the vector, See an example here

1. #Define a Vector
2. v <- c(10,20,30,40,50,60,70,80)
4. #Get element's value using boolean value
5. a <- v[c(TRUE,FALSE,FALSE,FALSE,TRUE,TRUE,FALSE,TRUE)]
7. #Print values
8. print(a)

and output is

1. [1] 10 50 60 80

Using negative value as index removes that particular element from the result, see an example

1. #Define a Vector
2. v <- c(10,20,30,40,50,60,70,80)
4. #Get element's value using negative index
5. a <- v[c(-2,-4,-6,-8)]
7. #Print values
8. print(a)

and output is

1. [1] 10 30 50 70

Arithmetic Operation in Vectors

We can perform variables like arithmetic operations (Addition, Subtraction, Multiplication, Divison) in vectors too.

1. #Add two vectors
2. a <- c(1, 2, 3)
3. b <- c(4, 5, 6)
5. # Addition
6. c <- a+b
8. # Subtraction
9. d <- a-b
11. # Multiplication
12. e <- a*b
14. # Divison
15. f <- a/b

now on printing this

1. > #Print Values
2. > cat("Addition",c)
3. Addition 5 7 9>
4. > cat("Subtraction",d)
5. Subtraction -3 -3 -3>
6. > cat("Multiplication",e)
7. Multiplication 4 10 18>
8. > cat("Divison",f)
9. Divison 0.25 0.4 0.5>

Modifying a Vector in R

We can modify vector’s elements values using index and assignment operator. See this example

1. #Define a Vector
2. v <- c(10,20,30,40,50,60,70,80)
4. #Modify 3rd element value
5. v[3] <- 33;
7. #Print Updated Vector
8. print(v)

and output is

1. [1] 10 20 33 40 50 60 70 80

Deleting a Vector in R

We can delete a vector by setting a vector to NULL.

1. #Define a Vector
2. v <- c(10,20,30,40,50,60,70,80)
4. #Set its value to NULL
5. v <- NULL
7. #Print Vector
8. print(v)

Cheers 🙂 Happy Learning

 Loops (R Loops) are used to repeat the execution of a block of statements based on some predefined conditions. In R Programming we have the following types of loops that can be used as per development requirements.

Repeat Loop in R Programming

Repeat loop in R executes the set of statements until the defined condition is satisfied

1. #Print some value using Repeat Loop
2. count <- 1
4. repeat {
5. print("R Programming")
6. count <- count+1
8. if(count > 5) {
9. break
10. }
11. }

and output is

1. [1] "R Programming"
2. [1] "R Programming"
3. [1] "R Programming"
4. [1] "R Programming"
5. [1] "R Programming"

Another Example

1. #Print table of 10 using Repeat Loop
2. a <- 10
3. count <- 1
5. repeat {
6. print(a*count)
7. count <- count+1
9. if(count > 10) {
10. break
11. }
12. }

and output is

1. [1] 10
2. [1] 20
3. [1] 30
4. [1] 40
5. [1] 50
6. [1] 60
7. [1] 70
8. [1] 80
9. [1] 90
10. [1] 100

While Loop in R Programming

While loop checks the condition before starting loop execution and executes the set of statements while the defined condition is true.

1. #Declare and Initialise a varable
2. a <- 1
4. #Check condition in a while loop
5. while(a<=5){
6. print(a)
7. a <- a+1
8. }

and output is

1. [1] 1
2. [1] 2
3. [1] 3
4. [1] 4
5. [1] 5

FOR Loop in R Programming

When you need to execute a code a specific number of times then FOR loop comes into action. Here we'll see how to iterate a vector using FOR loop.

1. #Declare and Initialise a Vector
2. a <- c(10,TRUE,"Ashish",2.4)
4. #Iterate vector using FOR loop
5. for(i in a){
6. print(i)
7. }

and output is

1. [1] "10"
2. [1] "TRUE"
3. [1] "Ashish"
4. [1] "2.4"

Cheers 🙂 Happy Learning

R Decision Making - IF...ELSE Statement in R Programming

We can write a simple IF statement, IF...ELSE statements or nested IF statements as per our requirement. If you know the basics of any other programming language then after this tutorial you'll get an idea about writing conditional statements in R programming.

Flow Chart of IF...ELSE is like this

Basic Syntax of IF-ELSE is like this in R

IF (Condition 1){
Statement to execute (if condition 1 is true)
}ELSE IF (Condition 2){
Statement to execute (if condition 2 is true)
}ELSE
Statement to execute (if condition 1& 2 both are false)

For a better understanding of decision-making, statements see this example

> #Declare Variables
> a <- 20
> b <- 40
> c <- 5
> 
> #Check conditions
> if(a>b && a>c){
+ print("Largest Value is A")
+ 
+ }else if(b>a && b>c){
+ print("Largest Value is B")
+ 
+ }else print("Largest Value is C-")
[1] "Largest Value is B"
>

This is how IF…ELSE works in R programming.

Cheers 🙂 Happy Learning