Sample code in flattening post doesn't run

Course Q&A Deep Learning Specialization Neural Networks and Deep Learning
1

@paulinpaloalto

I have seen your post about flattening an image. I want to play around with the code snippet that you provided in this thread:

If I try to run a cell like this one:

import numpy as np

# routine to generate a telltale 4D array to play with
def testarray(shape):
     (d1,d2,d3,d4) = shape
     A = np.zeros(shape)

for ii1 in range(d1):
    for ii2 in range(d2):
        for ii3 in range(d3):
            for ii4 in range(d4):
                A[ii1,ii2,ii3,ii4] = ii1 * 1000 + ii2 * 100 + ii3 * 10 + ii4 

return A

A = testarray((3,2,2,3))
Ashape1 = A.reshape(A.shape[0],-1).T
Ashape2 = A.reshape(-1,A.shape[0])
np.set_printoptions(suppress=True)
print("A.shape = " + str(A.shape))
print(A)
print("Ashape1.shape = " + str(Ashape1.shape))
print(Ashape1)
print("Ashape2.shape = " + str(Ashape2.shape))
print(Ashape2)

I get the following error:

NameError                                 Traceback (most recent call last)
<ipython-input-1-06a7c2dc17c6> in <module>
      6      A = np.zeros(shape)
      7 
----> 8 for ii1 in range(d1):
      9     for ii2 in range(d2):
     10         for ii3 in range(d3):

NameError: name 'd1' is not defined

Can you please help me get your code to run? Many thanks.

2

The indentation is wrong so that the “for” statement that is throwing the error is not part of the function. Indentation matters in python.

Oh, sorry, I just realized that this is my mistake! I didn’t copy/paste it correctly in the original post. I will fix it right now. Here is the correct version:

# routine to generate a telltale 4D array to play with
def testarray(shape):
    (d1,d2,d3,d4) = shape
    A = np.zeros(shape)

    for ii1 in range(d1):
        for ii2 in range(d2):
            for ii3 in range(d3):
                for ii4 in range(d4):
                    A[ii1,ii2,ii3,ii4] = ii1 * 1000 + ii2 * 100 + ii3 * 10 + ii4 

    return A

Thank you for pointing out my error so that I could correct it!

3

Many thanks for the fast reply. Now it worked.