Vector in R Programming

What are Vectors in R?

Vectors are the basic R data objects and there are 6 types of atomic vectors. They can be

• Integer,
• Logical,
• Double,
• Complex,
• Character and
• Raw

Creation of Vector

There are two types of vector creation:

• Single Element Vector
• Multiple Elements Vector

Single Element Vector

Whenever 1 word is written in R, it becomes a vector of length 1 and fits in one of the above vector types.

#Atomic vector of integer type
print(52L)
#Logical type
print(TRUE)

Output:

sol <- nchar("Counting number of
[1] 52      
[1] TRUE

Multiple Elements Vectors in R programming

• Using the Colon operator with numeric data

This operator helps in a constant change over the numeric data with limits.

Example:

#Creating sequence
a<- 4:10
b<-2.2:4.2
print(a)
print(b)

Output:

[1] 4 5 6 7 8 9 10
[1] 2.2 3.2 4.2

Using sequence(Seq.) operator

#Creating vector by incrementing by 0.2
print(seq(2, 3, by = 0.2))

Output:

[1]  2.0 2.2 2.4 2.6 2.8 3.0

• Accessing Vector Elements 

Indexing helps access the elements of a vector. The[ ] brackets are used for indexing.

Indexing starts with the number 1 position. A negative value in the index rejects that element from the output.  0 and 1 or TRUE and FALSE can be used for indexing.

#accessing vector elements
x<- c("letter one", "letter two", "letter three", "four", "five", "six")
b<- x[c(1,3,6)]
print(b)
#Usage of  logical Index
d<- x[c(FALSE, FALSE,TRUE,TRUE,FALSE)] 
print(d)
#Using negative indexing
e<- x[c(-1,-2,-3,-4)]
print(e)

Output:

[1] "letter one" "letter three" "six"
[1] "letter three" "four"
[1] "five" "six"

Vector Manipulation

• Vector Arithmetic

Two vectors having the same length can do arithmetic operations such as addition, subtraction, multiplication, and division to get vector output.

• Vector Element Recycling

When applying arithmetic operations to two vectors of unequal length, the elements of the shorter vector are recycled to complete the operations.

Example:

a <- c(2,4,6,8)
b <- c(3,8)
#b becomes c(3,8,3,8)
add.op <- a+b
print(add.op)

 Output:

[1]  5  12  9  16

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• Vector Element Sorting

The sorting of elements in a vector takes place in ascending or descending order. It can be either numbers or characters.

Example:

a <- c(2, 5, -6, 0) 
#sorting elements of vector
sort.sol <- sort(a)
print(sort.sol)
 
#sorting character vectors in decreasing order
b <- c("Blue", "Red", "Green")
revsort.sol <- sort(b, decreasing = TRUE)
print(revsort.sol) 

Output:

[1] -6 0 2 5
[1] "Blue" "Green" "Red"