for_loop_matrix_multiplication2.py

import numpy as np

def for_loop_matrix_multiplication2(A, B):
    """Second version of a for loop matrix multiplication.
    
    In this version, we remove the np.dot() function."""
    A = np.array(A)
    B = np.array(B)

    new_matrix = np.zeros((A.shape[0], B.shape[1]))

    for i, row in enumerate(A):
        for j, col in enumerate(B.T):
            # The zip function matches up the arrays nicely so that
            # values at the same index are paired up into a tuple.
            # Then, we unpack those tuples one by one, multiply the values
            # together, create a list with all those values, then sum the
            # values in the list.
            dot_product = sum([x*y for (x, y) in zip(row, col)])
            new_matrix[i, j] = dot_product
    
    return new_matrix