Sometimes while developing in Python, you need a quick way of enabling or disabling a large block of code for debugging

re = cv2.resize(img[ymin:ymax, xmin:xmax, :], (48, 48))

# Use a multi-line comment
"""
# Enable only if debugging
cv2.imshow("img", re)
cv2.waitKey(5000)
"""

Enabling or disabling this block this way, however, requires quite a bit of scrolling and editing1

Using a slightly different syntax, however, you can quickly flip the block on/off with a single edit:

re = cv2.resize(img[ymin:ymax, xmin:xmax, :], (48, 48))
# To enable, add a # at the start of the line below
#"""
# Enable only if debugging
cv2.imshow("img", re)
cv2.waitKey(5000)
#"""

A block can be enabled by just appending a # to the comment block starting (#===), and disabled by removing the #

# Enabled:
#"""
# Enable only if debugging
cv2.imshow("img", re)
cv2.waitKey(5000)
#"""

# Disabled (note the missing #):
"""
# Enable only if debugging
cv2.imshow("img", re)
cv2.waitKey(5000)
#"""

This can be very easily extended to toggling between two code blocks - the blocks can be switched by just appending the # to the first triple-quote line (or removing it):

# Enable first block
#"""
# Debugging value
PREDICT_THRESHOLD = 1000
"""
# Actual value
# Note that the block comment above does not have a starting #
PREDICT_THRESHOLD = 10
#"""

# Flip to the second block by removing the # from the line below
"""
# Debugging value
PREDICT_THRESHOLD = 1000
"""
# Actual value
# Note that the block comment above does not have a starting #
PREDICT_THRESHOLD = 10
#"""
Footnotes

  1. Unless using an IDE - this still requires selecting the code block, though ↩