# R - Vectors

Vectors are the most basic R data objects and there are six types of atomic vectors. They are logical, integer, double, complex, character and raw.

## Vector Creation

### Single Element Vector

Even when you write just one value in R, it becomes a vector of length 1 and belongs to one of the above vector types.

# Atomic vector of type character. print("abc"); # Atomic vector of type double. print(12.5) # Atomic vector of type integer. print(63L) # Atomic vector of type logical. print(TRUE) # Atomic vector of type complex. print(2+3i) # Atomic vector of type raw. print(charToRaw('hello'))

When we execute the above code, it produces the following result −

[1] "abc" [1] 12.5 [1] 63 [1] TRUE [1] 2+3i [1] 68 65 6c 6c 6f

### Multiple Elements Vector

**Using colon operator with numeric data**

# Creating a sequence from 5 to 13. v <- 5:13 print(v) # Creating a sequence from 6.6 to 12.6. v <- 6.6:12.6 print(v) # If the final element specified does not belong to the sequence then it is discarded. v <- 3.8:11.4 print(v)

When we execute the above code, it produces the following result −

[1] 5 6 7 8 9 10 11 12 13 [1] 6.6 7.6 8.6 9.6 10.6 11.6 12.6 [1] 3.8 4.8 5.8 6.8 7.8 8.8 9.8 10.8

**Using sequence (Seq.) operator**

# Create vector with elements from 5 to 9 incrementing by 0.4. print(seq(5, 9, by = 0.4))

When we execute the above code, it produces the following result −

[1] 5.0 5.4 5.8 6.2 6.6 7.0 7.4 7.8 8.2 8.6 9.0

**Using the c() function**

The non-character values are coerced to character type if one of the elements is a character.

# The logical and numeric values are converted to characters. s <- c('apple','red',5,TRUE) print(s)

When we execute the above code, it produces the following result −

[1] "apple" "red" "5" "TRUE"

## Accessing Vector Elements

Elements of a Vector are accessed using indexing. The **[ ] brackets** are used for indexing. Indexing starts with position 1. Giving a negative value in the index drops that element from result.**TRUE**,** FALSE** or **0** and **1** can also be used for indexing.

# Accessing vector elements using position. t <- c("Sun","Mon","Tue","Wed","Thurs","Fri","Sat") u <- t[c(2,3,6)] print(u) # Accessing vector elements using logical indexing. v <- t[c(TRUE,FALSE,FALSE,FALSE,FALSE,TRUE,FALSE)] print(v) # Accessing vector elements using negative indexing. x <- t[c(-2,-5)] print(x) # Accessing vector elements using 0/1 indexing. y <- t[c(0,0,0,0,0,0,1)] print(y)

When we execute the above code, it produces the following result −

[1] "Mon" "Tue" "Fri" [1] "Sun" "Fri" [1] "Sun" "Tue" "Wed" "Fri" "Sat" [1] "Sun"

## Vector Manipulation

### Vector arithmetic

Two vectors of same length can be added, subtracted, multiplied or divided giving the result as a vector output.

# Create two vectors. v1 <- c(3,8,4,5,0,11) v2 <- c(4,11,0,8,1,2) # Vector addition. add.result <- v1+v2 print(add.result) # Vector substraction. sub.result <- v1-v2 print(sub.result) # Vector multiplication. multi.result <- v1*v2 print(multi.result) # Vector division. divi.result <- v1/v2 print(divi.result)

When we execute the above code, it produces the following result −

[1] 7 19 4 13 1 13 [1] -1 -3 4 -3 -1 9 [1] 12 88 0 40 0 22 [1] 0.7500000 0.7272727 Inf 0.6250000 0.0000000 5.5000000

### Vector element recycling

If we apply arithmetic operations to two vectors of unequal length, then the elements of the shorter vector are recycled to complete the operations.

v1 <- c(3,8,4,5,0,11) v2 <- c(4,11) # V2 becomes c(4,11,4,11,4,11) add.result <- v1+v2 print(add.result) sub.result <- v1-v2 print(sub.result)

When we execute the above code, it produces the following result −

[1] 7 19 8 16 4 22 [1] -1 -3 0 -6 -4 0

### Vector Element Sorting

Elements in a vector can be sorted using the **sort()** function.

v <- c(3,8,4,5,0,11, -9, 304) # Sort the elements of the vector. sort.result <- sort(v) print(sort.result) # Sort the elements in the reverse order. revsort.result <- sort(v, decreasing = TRUE) print(revsort.result) # Sorting character vectors. v <- c("Red","Blue","yellow","violet") sort.result <- sort(v) print(sort.result) # Sorting character vectors in reverse order. revsort.result <- sort(v, decreasing = TRUE) print(revsort.result)

When we execute the above code, it produces the following result −

[1] -9 0 3 4 5 8 11 304 [1] 304 11 8 5 4 3 0 -9 [1] "Blue" "Red" "violet" "yellow" [1] "yellow" "violet" "Red" "Blue"