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Showing posts with label Arithmetic Operations. Show all posts
Showing posts with label Arithmetic Operations. Show all posts

## Saturday 18 August 2018

### 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.

## 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)
3. #Get element's value using index
4. a <- v[c(1,3,4,6)]
5. #Print values
6. 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)
3. #Get element's value using boolean value
4. a <- v[c(TRUE,FALSE,FALSE,FALSE,TRUE,TRUE,FALSE,TRUE)]
5. #Print values
6. 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)
3. #Get element's value using negative index
4. a <- v[c(-2,-4,-6,-8)]
5. #Print values
6. 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.

2. a <- c(1, 2, 3)
3. b <- c(4, 5, 6)
5. c <- a+b
6. # Subtraction
7. d <- a-b
8. # Multiplication
9. e <- a*b
10. # Divison
11. f <- a/b

now on printing this

1. > #Print Values
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)
3. #Modify 3rd element value
4. v[3] <- 33;
5. #Print Updated Vector
6. 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)
3. #Set its value to NULL
4. v <- NULL
5. #Print Vector
6. print(v)

Cheers ðŸ™‚ Happy Learning