NumPy: Exercises and Solutions

Activity in the left vs right brain

Exercise

• Read this dataset, which has been adapted from the StudyForrest project. It is an .npy file, which you can read with np.load().
• This will give you a 4D array with the following dimensions: left-to-right, back-to-front, bottom-to-top, time (1 sample per 2 s). Values in the array correspond to BOLD values (an indirect measure of brain activity).
• First, inspect the shape of the array to see how big each dimension is.
• Next, print out the average BOLD value separately for the left and the right side of the brain!

Solution

import numpy as np

a = np.load('data/fmri-data.npy')
print(a.shape)
m_left = a[:34].mean()
m_right= a[34:].mean()
print('M(left) = {:.2f}'.format(m_left))
print('M(right) = {:.2f}'.format(m_right))

Output:

(68, 84, 58, 90)
M(left) = 117.86
M(right) = 117.74

You're done with this section!