Numpy Vectors And Matrices

 

Numpy vectors and matrices will show up all the time in data science and machine learning.

So, let’s take a look at how to create them.

Let’s first import numpy.

import numpy as np

Next, let’s try to create our first vector row.

np.array([1,2,3,4])
# array([1, 2, 3, 4])

Wasn’t too bad was it?

Now, let’s try to make a single column vector.

np.array([[1],[2],[3],[4]])
# array([[1],[2],[3],[4]])

Now that we have created a row and a column, let’s combine these techniques to create a matrix.

np.array([[1,2,3,4],[1,2,3,4],[1,2,3,4],[1,2,3,4]])
# array([[1, 2, 3, 4],[1, 2, 3, 4],[1, 2, 3, 4],[1, 2, 3, 4]])

It is pretty straight forward but it is definitely useful to know!

Full code example:

import numpy as np

np.array([1,2,3,4])
# array([1, 2, 3, 4])

np.array([[1],[2],[3],[4]])
# array([[1],[2],[3],[4]])

np.array([[1,2,3,4],[1,2,3,4],[1,2,3,4],[1,2,3,4]])
# array([[1, 2, 3, 4],[1, 2, 3, 4],[1, 2, 3, 4],[1, 2, 3, 4]])