Handson-ml: plot_digits

[batblah]

I'm new to these libraries and while I was running the code in Chapter 3:

cl_a, cl_b = 3, 5
X_aa = X_train[(y_train == cl_a) & (y_train_pred == cl_a)]
X_ab = X_train[(y_train == cl_a) & (y_train_pred == cl_b)]
X_ba = X_train[(y_train == cl_b) & (y_train_pred == cl_a)]
X_bb = X_train[(y_train == cl_b) & (y_train_pred == cl_b)]

plt.figure(figsize=(8,8))
plt.subplot(221); plot_digits(X_aa[:25], images_per_row=5)
plt.subplot(222); plot_digits(X_ab[:25], images_per_row=5)
plt.subplot(223); plot_digits(X_ba[:25], images_per_row=5)
plt.subplot(224); plot_digits(X_bb[:25], images_per_row=5)

I get the following error:

---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-91-df1c82686923> in <module>()
      1 plt.figure(figsize=(8,8))
----> 2 plt.subplot(221); plot_digits(X_aa[:25], images_per_row = 5)
      3 plt.subplot(222); plot_digits(X_ab[:25], images_per_row=5)
      4 plt.subplot(223); plot_digits(X_ba[:25], images_per_row=5)
      5 plt.subplot(224); plot_digits(X_bb[:25], images_per_row=5)

NameError: name 'plot_digits' is not defined

I searched online but can't find resources on this plot_digits function. Can you help?

[ageron]

Hi @batblah ,

This function is defined in the Jupyter notebook (in cell In 8):

# EXTRA
def plot_digits(instances, images_per_row=10, **options):
    size = 28
    images_per_row = min(len(instances), images_per_row)
    images = [instance.reshape(size,size) for instance in instances]
    n_rows = (len(instances) - 1) // images_per_row + 1
    row_images = []
    n_empty = n_rows * images_per_row - len(instances)
    images.append(np.zeros((size, size * n_empty)))
    for row in range(n_rows):
        rimages = images[row * images_per_row : (row + 1) * images_per_row]
        row_images.append(np.concatenate(rimages, axis=1))
    image = np.concatenate(row_images, axis=0)
    plt.imshow(image, cmap = matplotlib.cm.binary, **options)
    plt.axis("off")

Make sure you run the cells in the Jupyter notebooks
in the right order, everything should work fine.

Hope this helps,
Aurélien

[Parikshit22]

thank you so much.

On Tue, Jul 24, 2018 at 6:40 PM Aurélien Geron [e-mail]
wrote:

Hi @batblah https://github.com/batblah ,

This function is defined in the Jupyter notebook (in cell In 8):

EXTRAdef plot_digits(instances, images_per_row=10, **options):

size = 28
images_per_row = min(len(instances), images_per_row)
images = [instance.reshape(size,size) for instance in instances]
n_rows = (len(instances) - 1) // images_per_row + 1
row_images = []
n_empty = n_rows * images_per_row - len(instances)
images.append(np.zeros((size, size * n_empty)))
for row in range(n_rows):
    rimages = images[row * images_per_row : (row + 1) * images_per_row]
    row_images.append(np.concatenate(rimages, axis=1))
image = np.concatenate(row_images, axis=0)
plt.imshow(image, cmap = matplotlib.cm.binary, **options)
plt.axis("off")

Make sure you run the cells in the Jupyter notebooks
in the right order, everything should work fine.

Hope this helps,
Aurélien

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[batblah]

Thanks for your reply.

[XxAakashxX]

Hey after defining that 'plot_digit' function I am getting this new zero divisibility error!

`---------------------------------------------------------------------------
ZeroDivisionError                         Traceback (most recent call last)
<ipython-input-64-46cb86a220bd> in <module>
      2 plt.subplot(221);plot_digits(X_aa[:25],images_per_row = 5)
      3 plt.subplot(222);plot_digits(X_ab[:25],images_per_row=5)
----> 4 plt.subplot(223);plot_digits(X_ba[:25],images_per_row = 5)
      5 plt.subplot(224);plot_digits(X_bb[:25],images_per_row=5)
      6 plt.show()

<ipython-input-63-a42fe1f80d92> in plot_digits(instances, images_per_row, **options)
      4     images_per_row = min(len(instances), images_per_row)
      5     images = [instance.reshape(size,size) for instance in instances]
----> 6     n_rows = (len(instances) - 1) // images_per_row + 1
      7     row_images = []
      8     n_empty = n_rows * images_per_row - len(instances)

ZeroDivisionError: integer division or modulo by zero`

[Euphoride]

Hi @XxAakashxX!

So it seems that when we define cl_a and cl_b, from now on we have to define them as characters and not integers (as the y_train and y_train_pred labels are characters and not integers)

So in your code, replace
cl_a, cl_b = 3, 5

with
cl_a, cl_b = '3', '5'

Hope this helps!