R Programming: Create and Fill 5x4, 3x3 Matrices with Labels

R Programming: Basic Exercise-16 with Solution

Write a R program to create a 5 × 4 matrix , 3 × 3 matrix with labels and fill the matrix by rows and 2 × 2 matrix with labels and fill the matrix by columns.

Sample Solution :

R Programming Code :

# Create a 5x4 matrix with elements from 1 to 20
m1 = matrix(1:20, nrow=5, ncol=4)

# Print a message indicating the following matrix is 5x4
print("5 × 4 matrix:")

# Print the 5x4 matrix
print(m1)

# Define a vector of cells for a 3x3 matrix
cells = c(1,3,5,7,8,9,11,12,14)

# Define row names for the 3x3 matrix
rnames = c("Row1", "Row2", "Row3")

# Define column names for the 3x3 matrix
cnames = c("Col1", "Col2", "Col3")

# Create a 3x3 matrix with specified cells, filled by rows, and with row and column names
m2 = matrix(cells, nrow=3, ncol=3, byrow=TRUE, dimnames=list(rnames, cnames))

# Print a message indicating the following matrix is 3x3 with labels, filled by rows
print("3 × 3 matrix with labels, filled by rows: ")

# Print the 3x3 matrix filled by rows with labels
print(m2)

# Print a message indicating the following matrix is 3x3 with labels, filled by columns
print("3 × 3 matrix with labels, filled by columns: ")

# Create a 3x3 matrix with specified cells, filled by columns, and with row and column names
m3 = matrix(cells, nrow=3, ncol=3, byrow=FALSE, dimnames=list(rnames, cnames))

# Print the 3x3 matrix filled by columns with labels
print(m3)

Output:

[1] "5 × 4 matrix:"
     [,1] [,2] [,3] [,4]
[1,]    1    6   11   16
[2,]    2    7   12   17
[3,]    3    8   13   18
[4,]    4    9   14   19
[5,]    5   10   15   20
[1] "3 × 3 matrix with labels, filled by rows: "
     Col1 Col2 Col3
Row1    1    3    5
Row2    7    8    9
Row3   11   12   14
[1] "3 × 3 matrix with labels, filled by columns: "
     Col1 Col2 Col3
Row1    1    7   11
Row2    3    8   12
Row3    5    9   14                         

Explanation:

• Create a 5 × 4 Matrix:
• m1 = matrix(1:20, nrow=5, ncol=4): Creates a 5x4 matrix with numbers from 1 to 20, filled column-wise by default.
• print("5 × 4 matrix:"): Prints a label for the matrix.
• print(m1): Displays the 5x4 matrix.
• Create a 3 × 3 Matrix with Labels (Filled by Rows):
• cells = c(1,3,5,7,8,9,11,12,14): Defines the values to be used in the matrix.
• rnames = c("Row1", "Row2", "Row3"): Specifies row names for the matrix.
• cnames = c("Col1", "Col2", "Col3"): Specifies column names for the matrix.
• m2 = matrix(cells, nrow=3, ncol=3, byrow=TRUE, dimnames=list(rnames, cnames)): Creates a 3x3 matrix using the cells vector, filled by rows (byrow=TRUE), and assigns row and column names.
• print("3 × 3 matrix with labels, filled by rows: "): Prints a label for this matrix.
• print(m2): Displays the 3x3 matrix filled by rows with labels.
• Create a 3 × 3 Matrix with Labels (Filled by Columns):
• m3 = matrix(cells, nrow=3, ncol=3, byrow=FALSE, dimnames=list(rnames, cnames)): Creates a 3x3 matrix using the cells vector, filled by columns (byrow=FALSE), and assigns row and column names.
• print("3 × 3 matrix with labels, filled by columns: "): Prints a label for this matrix.
• print(m3): Displays the 3x3 matrix filled by columns with labels.

R Programming Code Editor:

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