Python, Machine Learning, Numpy, Matplotlib.
np.array([[1, 2, 3], [4, 5, 6]]) print("Matrix A: \n") print(A) print("\nMatrix B: \n") print(B) Image from author # Indexing/Slicing examples print(A[0, :]) # index the first "row" and all columns print(A[1, 2]) # index the second row, third column entry print(A[:, 1]) # index entire second column