Write your code: Matrix transpose#

Write functions that return the transpose of a matrix A.

Rules#

Function returns an numpy array.
You must not use any external function to calculate the transpose.
Function should work for square and non-square matrix.

Useful Links#

Transpose

Transpose overview#

Consider a matrix \(A\) of order \(j\times i\). The transpose of a matrix \(A\), denoted by \(A^T\), may be constructed by writing the columns of \(A\) as the rows of \(A^T\).

Formally, in the i-th row, j-th column element of \(A^T\) is the j-th row, i-th column element of \(A\):

\[ [A^T]_{i, j} = A_{j,i}\]

Example#

Consider the following matrix \(A\):

\[\begin{split} A = \begin{bmatrix} 1 & 2 & 3\\ 4 & 5 & 6 \end{bmatrix} \end{split}\]

The transpose is:

\[\begin{split} A^T = \begin{bmatrix} 1 & 4\\ 2 & 5 \\ 3 & 6 \end{bmatrix} \end{split}\]

Function Definition#

Solution#

import numpy as np

A = np.array([[4, 7, 3],
              [2, 5, 6]])

def get_transpose(A):
    
    # write your function here
    
get_transpose(A)

  File "/tmp/ipykernel_1959/1770882093.py", line 5
    get_transpose(A)
                ^
IndentationError: expected an indented block

Testing#

Check if your function returns the expected value using the cell below.

import unittest

class UnitTests(unittest.TestCase):
    def setUp(self):
        self.A = np.array([[1, 2, 3],
                           [4, 5, 6],
                           [7, 8, 9]]
                         )
        self.R = np.array([[1, 2, 3]]
                         )
        self.C = np.array([[1],
                           [2],
                           [3]]
                         )                         
    def test_type(self):
        self.assertTrue(isinstance(get_transpose(self.A), np.ndarray), 'The function should return a NumPy array')
    def test_square(self):
        self.assertTrue((get_transpose(self.A)==np.array([[1, 4, 7],[2, 5, 8],[3, 6, 9]])).all())
    def test_row(self):
        self.assertTrue((get_transpose(self.R)==np.array([[1],[2],[3]])).all())
    def test_column(self):
        self.assertTrue((get_transpose(self.C)==np.array([[1,2,3]])).all())
unittest.main(argv=[''], verbosity=2,exit=False)

Python Challenges

Write your code: Matrix transpose

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