R

How to Create Matrix and Perform Arithmetic Operations in R

In this R tutorial, we will discuss about matrix() functions with the different parameters. Afterwards, we will see how to perform the different arithmetic operations on matrices.

Generally, we can say that a matrix stores values in rows and columns. From this, we can say that the matrix is a 2D data structure.

Creating Matrix in R

We can create a matrix in R by using the matrix() function.

Syntax:

matrix(input_object,nrow,ncol)

Parameters:

  1. input_object is used to create a matrix . It refers to lists, vectors, etc.
  2. nrow stands for the number of rows that specifies the  number of rows for a matrix_object.
  3. ncol stands for the number of columns that  specifies the  number of columns for a matrix_object.

Example 1:

In this example, we will create a matrix from the vector elements.

#create vector for fruits

fruits=c(23,4,43,3,4,5,6,7,8,967,65,43,5,56,78)

 

#pass the vector to a matrix

matrix_object=matrix(fruits)

 

print(matrix_object)

Result:

We just passed the input parameter, i.e. vector with 15 elements. Now, we will see the examples by passing the nrow and ncol parameters.

Example 2:

In this example, we will create a matrix from the vector elements by specifying the nrow parameter.

#create vector for fruits

fruits=c(23,4,43,3,4,5,6,7,8,967,65,43,5,56,78,67)

 

#pass the vector to a matrix with 4 rows

matrix_object=matrix(fruits,nrow=4)

 

print(matrix_object)

Result:

We just passed the input parameter, i.e. vector with 16 elements. And the matrix has 4 rows.

Example 3:

In this example, we will create a matrix from the vector elements by specifying the ncol parameter.

#create vector for fruits

fruits=c(23,4,43,3,4,5,6,7,8,967,65,43,5,56,78,67)

 

#pass the vector to a matrix with 4 columns

matrix_object=matrix(fruits,ncol=4)

 

print(matrix_object)

Result:

We just passed the input parameter, i.e. vector with 16 elements. And the matrix has 4 columns.

Now, let’s perform the arithmetic operations on the two matrices.

Here, the computation is done element wise in both the matrices.

Example 1:

In this example, we will create two matrices with 5 rows and 4 columns and perform an addition operation.

#create vector for fruits

fruits=c(23,4,43,3,4,5,6,7,8,967,65,43,5,56,78,67,45,44,67,665)

 

#pass the vector to a matrix with 5 rows and 4 columns

matrix_object1=matrix(fruits,nrow=5,ncol=4)

 

#create vector for vegetables

vegetables=c(23,4,43,3,4,5,6,7,8,967,65,43,5,56,78,67,87,90,87,0)

 

#pass the vector to a matrix with 4 rows

matrix_object2=matrix(vegetables,nrow=5,ncol=4)

 

print(matrix_object1)

 

print(matrix_object2)

 

print("Addition: ")

#add 2 matrices

print(matrix_object1+matrix_object2)

Result:

We can see that the elements in the first matrix are added to the second matrix.

Example 2:

In this example, we will create two matrices with 5 rows and 4 columns and perform a subtraction operation.

#create vector for fruits

fruits=c(23,4,43,3,4,5,6,7,8,967,65,43,5,56,78,67,45,44,67,665)

 

#pass the vector to a matrix with 5 rows and 4 columns

matrix_object1=matrix(fruits,nrow=5,ncol=4)

 

#create vector for vegetables

vegetables=c(23,4,43,3,4,5,6,7,8,967,65,43,5,56,78,67,87,90,87,0)

 

#pass the vector to a matrix with 4 rows

matrix_object2=matrix(vegetables,nrow=5,ncol=4)

 

print(matrix_object1)

 

print(matrix_object2)

 

print("Subtraction: ")

#add 2 matrices

print(matrix_object1-matrix_object2)

Result:

We can see that the elements in the second matrix are subtracted from the first matrix.

Example 3:

In this example, we will create two matrices with 5 rows and 4 columns and perform a multiplication operation.

#create vector for fruits

fruits=c(23,4,43,3,4,5,6,7,8,967,65,43,5,56,78,67,45,44,67,665)

 

#pass the vector to a matrix with 5 rows and 4 columns

matrix_object1=matrix(fruits,nrow=5,ncol=4)

 

#create vector for vegetables

vegetables=c(23,4,43,3,4,5,6,7,8,967,65,43,5,56,78,67,87,90,87,0)

 

#pass the vector to a matrix with 4 rows

matrix_object2=matrix(vegetables,nrow=5,ncol=4)

 

print(matrix_object1)

 

print(matrix_object2)

 

print("Multiplication: ")

#add 2 matrices

print(matrix_object1*matrix_object2)

Result:

We can see that the elements from the first matrix are multiplied with the elements in the second matrix.

Example 4:

In this example, we will create two matrices with 5 rows and 4 columns and perform a division operation.

#create vector for fruits

fruits=c(23,4,43,3,4,5,6,7,8,967,65,43,5,56,78,67,45,44,67,665)

 

#pass the vector to a matrix with 5 rows and 4 columns

matrix_object1=matrix(fruits,nrow=5,ncol=4)

 

#create vector for vegetables

vegetables=c(23,4,43,3,4,5,6,7,8,967,65,43,5,56,78,67,87,90,87,0)

 

#pass the vector to a matrix with 4 rows

matrix_object2=matrix(vegetables,nrow=5,ncol=4)

 

print(matrix_object1)

 

print(matrix_object2)

 

print("Division: ")

#add 2 matrices

print(matrix_object1/matrix_object2)

Result:

We can see that the elements from the first matrix are divided by the elements in the second matrix.

Conclusion

In this R tutorial, we saw how to create a matrix using the matrix() function. After that, we performed the different arithmetic operations like addition, subtraction, multiplication, and division.

About the author

Sireesha Lavu

This is Sireesha Lavu from Gogulamudi, Andhra Pradesh, India 522015.
I am currently working as a teacher and interested in writing technical articles on computer science.