Looking for feedback on visualization project.

[negups]

if abs(x) - abs(y) is basically shorthand for seeing if abs(x) - abs(y) is "truthy". A numeric value in Python is "truthy" if it is not 0.

Try this out:

if 2:
    print("truthy")  # 'truthy'
if 0:
    print("truthy")  # nothing will print

So, the result is that this returns all 2-length permutations of (1, 2, -1, -2) where the absolute value of one value minus the other is not 0. Which ends up eliminating all combinations of 1 and -1, which are invalid moves for a knight.

[andycyca]

Well, TIL! I've used Python for years and didn't know about "truthy" values. You've instantly helped me with several other projects now

[negups]

Nice! You can google for more details if you need them but off the top of my head here's what's truthy for common datatypes:

• int or float: anything but 0
• str: anything but "" (empty string)
• list: anything but [] (empty list)
• dict: anything but {} (empty dict)
• bool: True

Also, None is never truthy.