Rotate a Given Matrix 90 Degrees Clockwise in R Programming

R Programming: Matrix Exercise-12 with Solution

Write a R program to rotate a given matrix 90 degree clockwise rotation.

Sample Solution:

R Programming Code:

# Create a 3x3 matrix with values from 1 to 9
x = matrix(1:9, 3)

# Print the original matrix
print("Original matrix:")
print(x)

# Rotate the matrix 90 degrees clockwise
# Step 1: Reverse the elements of each column using 'rev'
# Step 2: Apply the reverse operation to each column with 'apply'
# Step 3: Transpose the resulting matrix using 't'
rotate = t(apply(x, 2, rev))

# Print the rotated matrix
print("Rotate the said matrix 90 degree clockwise:")
print(rotate)

Output:

[1] "Original matrix:"
     [,1] [,2] [,3]
[1,]    1    4    7
[2,]    2    5    8
[3,]    3    6    9
[1] "Rotate the said matrix 90 degree clockwise:"
     [,1] [,2] [,3]
[1,]    3    2    1
[2,]    6    5    4
[3,]    9    8    7               

Explanation:

• Create a Matrix:
• x = matrix(1:9, 3)
• Creates a 3x3 matrix with values from 1 to 9. The matrix is filled by column by default.
• Print the Original Matrix:
• print("Original matrix:")
• Prints the label "Original matrix:".
• print(x)
• Prints the contents of the matrix x.
• Rotate the Matrix 90 Degrees Clockwise:
• rotate = t(apply(x, 2, rev))
• apply(x, 2, rev):
• Applies the rev function to each column (2 indicates column-wise operation) of the matrix x. This reverses the order of elements in each column.
• t(...):
• Transposes the matrix resulting from the apply function, effectively rotating the original matrix 90 degrees clockwise.
• Print the Rotated Matrix:
• print("Rotate the said matrix 90 degree clockwise:")
• Prints the label "Rotate the said matrix 90 degree clockwise:".
• print(rotate)
• Prints the contents of the rotated matrix.

R Programming Code Editor:

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