Matrix Transpose in R

Transpose of a matrix is an operation in which we convert the rows of the matrix in column and column of the matrix in rows. The general equation for performing the transpose of a matrix is as follows.

Aij = Aji  where i is not equal to j

Example:

Matrix M ---> [1, 8, 9
               12, 6, 2
               19, 42, 3]

Transpose of M
Output --->   [1, 12, 19
               8, 6, 42,
               9, 2, 3]

Transpose of a Matrix can be performed in two ways:

• Finding the transpose by using the t() function 

# R program for Transpose of a Matrix

# create a matrix with 2 rows
# using matrix() method
M <- matrix(1:6, nrow = 2)

# print the original matrix
print(M)

# transpose of matrix
# using t() function.
t <- t(M)

# print the transpose matrix
print(t)

• Output:

     [, 1] [, 2] [, 3]
[1, ]    1    3    5
[2, ]    2    4    6

     [, 1] [, 2]
[1, ]    1    2
[2, ]    3    4
[3, ]    5    6

• By iterating over each value using Loops: 

# create matrix with 3 rows and 3 columns
Matrix = matrix(1:9, nrow = 3)

# print the matrix
print(Matrix)

# create another matrix
M2 = Matrix

# Loops for Matrix Transpose
for (i in 1:nrow(M2))
{
    # iterate over each row
    for (j in 1:ncol(M2))
    {
        # iterate over each column
        # assign the correspondent elements
        # from row to column and column to row.
        M2[i, j] <- Matrix[j, i]
    }
}

# print the transposed matrix
print(M2)

• Output:

     [,1] [,2] [,3]
[1,]    1    4    7
[2,]    2    5    8
[3,]    3    6    9
     [,1] [,2] [,3]
[1,]    1    2    3
[2,]    4    5    6
[3,]    7    8    9