# Vectors

**Vectors** are used to store multiple values of the same data type for later use. Unlike other programming languages, vectors in R are not zero-indexed; they start from 1.

## Vector Types

Atomic vectors are made with the ‘c()’ function to combine different elements of the same type together:

`atomic_vector <- c(element_1, element_2, ... element_N)`

Recursive vectors can have elements of any data type and is created with the `list()`

function:

`recursive_vector <- list(element_1, element_2, ... element_N)`

## Examples

The following atomic vectors are created with the `c()`

function:

# Character vectornames <- c('Adam', 'John', 'Walter')# Integer vectormarks <- c(90, 87, 100, 79, 91)# Logical vectorbooleans <- c(TRUE, FALSE, TRUE)

Apart from the ‘c()’ function, the colon operator (`:`

) can be used to create a vector containing a range of numbers:

# This vector contains all the numbers between 1 and 10numbers <- 1:10numbers# Output: [1] 1 2 3 4 5 6 7 8 9 10

In R, character vectors can contain alphanumeric values and special characters.

alphanumerics <- c('water', 'fire', 'ice', 90)alphanumerics# Output: [1] "water" "fire" "ice" "90"

## Accessing Vector Elements

The most common way to access vector elements is by index using the subscript operator `[]`

:

numbers <- c(65, 49, 55, 36, 126)numbers[2]numbers[4]

The output would look like this:

[1] 49[1] 36

Vector elements can also be accessed by logical indexing:

# Accessing vector elements using logical indexing.numbers <- c(1, 2, 3, 4, 5)numbers[numbers < 4]

This would produce the following output:

[1] 1 2 3

## Updating a Vector

Vector elements can be updated by specifying the index with the subscript operator (`[]`

) and replacing with the new value:

numbers <- c(2, 5, 1, 7, 9)cat("Original vector: ", numbers, "\n")numbers[3] = 8cat("Third element changed: ", numbers, "\n")numbers[1] = 0cat("First element changed: ", numbers)

To start, the third element in `numbers`

is updated to 8. Next, the first element is updated to 0. This will produce the following output:

Original vector: 2 5 1 7 9Third element changed: 2 5 8 7 9First element changed: 0 5 8 7 9

## Vector Recycling

Vector recycling is a process in which two vectors of different lengths are operated upon such that the elements of the shorter vector are repeated to match the length of the longer vector.

### Example

The following example presents two cases of vector recycling using addition, which requires the two vectors to be equal in length.

Case 1 is when the two vector lengths are equal:

numbers_1 <- c(1, 2, 3, 4, 5)numbers_2 <- c(3, 4, 5, 6, 7)sum <- numbers_1 + numbers_2sum# Output: [1] 4 6 8 10 12

Case 2 is when the vector lengths are unequal:

numbers_1 <- c(1, 2, 3, 4, 5, 6)numbers_2 <- c(3, 4)sum <- numbers_1 + numbers_2sum# Output: [1] 4 6 6 8 8 10

Here, the first two elements of `numbers_1`

are added to the first, and only, two elements of `numbers_2`

. Then, to complete the addition operation, R repeats (or recycles) the elements of the smaller `numbers_2`

vector (`3`

and `4`

) until the end of `numbers_1`

is reached.

## Contributors

- Anonymous contributor