Why do I get "IndentationError: expected an indented block" in my code

April 25, 2022

I want to detect edges in an image. This is the code I used:

fig, axs = plt.subplots(nrows=3, ncols=3, figsize=(15,8))
# Liste des valeurs
Val1 = [50, 100, 400]
Val2 = [50, 100, 400]
for i, val1 in enumerate(Val1):
for j, val2 in enumerate(Val2):
edge_image = cv2.Canny(image, val1 , val2)
axs[i][j].imshow(edge_image, cmap = 'Greys_r')
axs[i][j].set_title((val1,val2))
axs[i][j].set_axis_off()

When I run it I get the error:

File "<ipython-input-16-d6d5d4b1d7c6>", line 6
    for j, val2 in enumerate(Val2):
      ^
IndentationError: expected an indented block

How can I fix this?

>Solution :

Python needs indentation to separate code blocks.just like braces does in other languages. try to indent your code with tab or 2 spaces(According to PEP-8).reply if the error still persists.
Your code must indent like this

fig, axs = plt.subplots(nrows=3, ncols=3, figsize=(15,8))
# Liste des valeurs
Val1 = [50, 100, 400]
Val2 = [50, 100, 400]
for i, val1 in enumerate(Val1):
  for j, val2 in enumerate(Val2):
    edge_image = cv2.Canny(image, val1 , val2)
    axs[i][j].imshow(edge_image, cmap = 'Greys_r')
    axs[i][j].set_title((val1,val2))
    axs[i][j].set_axis_off()