Matrix transpose in Python.

When a matrix is transposed, its rows and columns are switched like this:

The list comprehension to do this looks like this:

def transpose_matrix(matrix):
    return [[row[col] for row in matrix] for col, _ in enumerate(matrix[0])]

The matrix should have a rectangular form. All rows should be of equal size and all columns should be of equal size.

Here is a test program that uses the transpose function:

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

def print_matrix(matrix):
    for row in matrix:
        print(" ".join([str(col) for col in row]))
    print()

def transpose_matrix(matrix):
    return [[row[col] for row in matrix] for col, _ in enumerate(matrix[0])]

print_matrix(matrix)
transposed_matrix = transpose_matrix(matrix)
print_matrix(transposed_matrix)
transposed_again_matrix = transpose_matrix(transposed_matrix)
print_matrix(transposed_again_matrix)

Output:

1 2 3
4 5 6

1 4
2 5
3 6

1 2 3
4 5 6