Arrays and Matrices in R programming | R Programming Solved Assignment

Assignment 5: Arrays and Matrices in R programming

1. Write a R program to create an array of two 3x3 matrices each with 3 rows and 3 columns from two given two vectors.

Answer:

v1 = c(1,3,4,5) v2 = c(10,11,12,13,14,15) result = array(c(v1,v2),dim = c(3,3,2)) print(result)

2. Write a R program to create a blank matrix.

Answer :

m = matrix(, nrow = 3, ncol = 3) print("Empty matrix of 3 rows and 3 columns:") print(m)

3. Write a R program to create a matrix taking a given vector of numbers as input. Display the matrix.

Answer :

row_names = c("row1", "row2", "row3", "row4") col_names = c("col1", "col2", "col3", "col4") M = matrix(c(1:16), nrow = 4, byrow = TRUE, dimnames = list(row_names, col_names)) print("Original Matrix:") print(M)

4. Write a R program to create a two-dimensional 5x3 array of sequence of even integers greater than 50.

Answer :

a <- array(seq(from = 50, length.out = 15, by = 2), c(5, 3)) print("5×3 array of sequence of greater than 50:") print(a)

5. Write a R program to convert a given matrix to a 1 dimensional array.

Answer :

m=matrix(1:12,3,4) a = as.vector(m) print("1 dimensional array:") print(a)

SET A:

1. Write a R program to create a matrix taking a given vector of numbers as input. Display the matrix.

Answer :

row_names = c("row1", "row2", "row3", "row4") col_names = c("col1", "col2", "col3", "col4") M = matrix(c(1:16), nrow = 4, byrow = TRUE, dimnames = list(row_names, col_names)) print("Original Matrix:") print(M)

2. Write a R program to create a matrix taking a given vector of numbers as input and define the column and row names. Display the matrix.

Answer : 

row_names = c("row1", "row2", "row3", "row4") col_names = c("col1", "col2", "col3", "col4") M = matrix(c(1:16), nrow = 4, byrow = TRUE, dimnames = list(row_names, col_names)) print(M)

3. Write a R program to access the element at 3rd column and 2nd row, only the 3rd row and only the 4th column of a given matrix.

Answer :

row_names = c("row1", "row2", "row3", "row4") col_names = c("col1", "col2", "col3", "col4") M = matrix(c(1:16), nrow = 4, byrow = TRUE, dimnames = list(row_names, col_names)) print("Original Matrix:") print(M) print("Access the element at 3rd column and 2nd row:") print(M[2,3]) print("Access only the 3rd row:") print(M[3,]) print("Access only the 4th column:") print(M[,4])

4. Write an R program to create three vectors a,b,c with 3 integers. Combine the three vectors to become a 3×3 matrix where each column represents a vector. Print the content of the matrix.

Answer:

a<-c(1,2,3) b<-c(4,5,6) c<-c(7,8,9) m<-cbind(a,b,c) print("Content of the matrix:") print(m)

5. Write an R program to create a list of elements using vectors, matrices and a functions. Print the content of the list.

Answer :

l = list(c(1, 2, 2, 5, 7, 12),month.abb,matrix(c(3, -8, 1, -3), nrow = 2),asin) print(l)

SET B:

1. Write a R program to create an array of three 3x2 matrices each with 3 rows and 2 columns from two given two vectors of different length.

Answer :

v1 = c(1,3,4,5) v2 = c(10,11,12,13,14,15) result = array(c(v1,v2),dim = c(3,2,3)) print("New array:") print(result)

2. Write a R program to create an array of two 3x3 matrices each with 3 rows and 3 columns from two given two vectors. Print the second row of the second matrix of the array and the element in the 3rd row and 3rd column of the 1st matrix.

Answer :

v1 = c(1,3,4,5) v2 = c(10,11,12,13,14,15) result = array(c(v1,v2),dim = c(3,3,2)) print("New array:") print(result) print("The second row of the second matrix of the array:") print(result[2,,2]) print("The element in the 3rd row and 3rd column of the 1st matrix:") print(result[3,3,1])

3. Write a R program to access the element at 3rd column and 2nd row, only the 3rd row and only the 4th column of a given matrix.

Answer :

row_names = c("row1", "row2", "row3", "row4") col_names = c("col1", "col2", "col3", "col4") M = matrix(c(1:16), nrow = 4, byrow = TRUE, dimnames = list(row_names, col_names)) print("Access the element at 3rd column and 2nd row:") print(M[2,3]) print("Access only the 3rd row:") print(M[3,]) print("Access only the 4th column:") print(M[,4])

 4. Write a R program to create two 2x3 matrices and add, subtract, multiply and divide the matrix elements.

Answer :

m1 = matrix(c(1, 2, 3, 4, 5, 6), nrow = 2) m2 = matrix(c(0, 1, 2, 3, 0, 2), nrow = 2) result = m1 + m2 print("Result of addition") print(result) result = m1 - m2 print("Result of subtraction") print(result) result = m1 * m2 print("Result of multiplication") print(result) result = m1 / m2 print("Result of division:") print(result)

5. Write an R program to convert a given matrix to a list and print list in ascending order.

Answer :

x = matrix(1:12, ncol=3) print("Original matrix:") print(x) print("list from the said matrix:") l = split(x, rep(1:ncol(x), each = nrow(x))) c <-(unlist(l)) sort(c)

SET C:

1. Write a R program to combine three arrays so that the first row of the first array is followed by the first row of the second array and then first row of the third array.

Answer :

num1 = rbind(rep("A",3), rep("B",3), rep("C",3)) num2 = rbind(rep("P",3), rep("Q",3), rep("R",3)) num3 = rbind(rep("X",3), rep("Y",3), rep("Z",3)) a = matrix(t(cbind(num1,num2,num3)),ncol=3, byrow=T) print("Combine three arrays") print(a)

2. Write a R program to find row and column index of maximum and minimum value in a given matrix.

Answer :

m = matrix(c(1:16), nrow = 4, byrow = TRUE) result = which(m == max(m), arr.ind=TRUE) print("Row and column of maximum value of the said matrix:") print(result) result = which(m == min(m), arr.ind=TRUE) print("Row and column of minimum value of the said matrix:") print(result)