Data Structure: Vector

↪ Creating Vector

A vector in R can contain any number of elements, but all of the elements must be of the same type – that is a vector cannot contain a mix of numbers, logical, and character types.

The c() function is used for creating the Vector. “=” or “->” can be used as an assignment operator.

      x = c(5,8,10,12)
      x

      ---Output---
      [1]  5  8 10 12

The vector can also be given a name using the <- operator, much like the = assignment operator.

      x <- c("A","B","X","Z")
      x

      —Output—
      [1] “A” “B” “X” “Z”

The typeof() function is used for finding the data type present in the vector.

      typeof(x)

      ---Output---
      [1] "double"

By default, a number is considered double in R. To create an integer Vector, append the number by L.

      x = c(5L,8L,10L,12L)
      typeof(x)

      ---Output---
      [1] "integer"

Data Structure: Vector

↪ Vector of Sequence

The ':' operator is used for creating a sequence with the vector function c().

      x = c(1:15)
      x

      ---Output---
      [1]  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15

A sequence can be created simply by

      x = 1:15
      x

The seq() function is used for creating a sequence.

      x = seq(1,15)
      x

Sequence with increment value.

      x = seq(1,15,3)
      x

      ---Output---
      [1]  1  4  7 10 13

Another example of sequence with fraction incremental value.

      x = seq(0,1,0.1)
      x

      ---Output---
      [1] 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Data Structure: Vector

↪ Accessing an element in the vector

Accessing an element using an index.

      x[3]

Accessing range of elements in the vector.

      x[5:8]

Exclude an item

      x = c(10,20,30,40)
      x[-3]

      ---Output---
      [1] 10 20 40

A logical vector can be used to indicate whether an item should be included.

      x[c(TRUE,FALSE,FALSE,TRUE)]

      ---Output---
      [1] 10 40

Data Structure: Vector

↪ Arithmetic Operations

Arithmetic operations can be performed when the two vectors are of same length.

      x = c(10,20,30,40)
      y = c(20,30,40,50)
      x + y                # Prints [1] 30 50 70 90
      y-x                  # Prints [1] 10 10 10 10
      x*y                  # Prints [1]  200  600 1200 2000
      y/x                  # Prints [1] 2.000000 1.500000 1.333333 1.250000

Other singular arithmetic operations on Vector are possible.

      x^2                  # Prints [1]  100  400  900 1600
      sqrt(x)              # Prints [1] 3.162278 4.472136 5.477226 6.324555