Review: Debugging Questions (NumPy)

Module 4: IDEs & Tools

Debugging Questions (NumPy)

import numpy as np

Exercise

The code aims to reshape a flat array into a 3D array. However, it results in an error. Identify and fix the error(s).

arr = np.arange(27)
arr_3d = arr.reshape((3, 3))  # Error
print("3D Array:\n", arr_3d)

Exercise

The code is supposed to compute the cumulative product of an array. However, it gives incorrect output. Identify and fix the error(s).

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

cum_prod = np.cumsum(arr, axis=0)
print("Cumulative product:", cum_prod)
# Expected: [[1, 2, 6, 24]]
# Output: [[1 2 3 4]]

Exercise

This code attempts to select elements from a NumPy array based on a condition. However, it raises an error ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all(). Identify and fix the error(s).

arr = np.arange(10)

# Select elements greater than 5 and less than 8
selected = arr[arr > 5 and arr < 8.0]  # Error
print("Selected elements:", selected)  # Expected: [6, 7]

Exercise

You wrote the following code to see how fixing a seed ensures the random generators always return the same number. However, every step of the for loop shows a different number. What is happening?

for _ in range(10):
  x = np.random.randint(low=0, high=1000)
  np.random.seed(x)
  print(x)