Can someone explain the line "if not symmetric_difference.?

Hi David,

It's true that the symmetric difference is everything not in the intersection but checking if there's no symmetric difference is not the same as getting the intersection.

The logic in the code is checking if there is no symmetric difference. Meaning, the sets completely intersect.

If you get the intersection between the two, then you'll only know that at least some correct guesses have been made. You wouldn't know if they completely intersect and all the correct guesses have been made. Additional logic would be needed to make intersection work out.

I think another way you could approach the logic is to check if the 2 sets are equal.

if word_set == correct:

Since "symmetric_difference" returns all of the items that are not in both sets... "if not symmetric_ difference" is only True if the sets are identical ....try this in the shell.... s1 = {1, 2, 3}

s2 = {1, 2, 3, 4}

if s1 ^ s2: print(True)

if not s1 ^ s2: print(True)

then make the sets identical and try again.....it's just another way of establishing a boolean value in a conditional....

more to the point.....the "empty set" returns False therefore, if the symmetric_difference is the empty set......it's False... soooo..... not symmetric_difference is True

What helps me sometimes is constructing plain English sentences out of code. For instance:

if not word_set.symmetric_difference(correct):

would read in English as, "If the word set and the set of correct guesses are exactly the same..." while :

if word_set.intersection(correct):

would read as,"If the word set and the set of correct guesses have common values..."

if not symmetric_difference(): is checking for a bool output.....If symetric_difference() returns a False do to an empty set(), which means they both have the same set values, then the not makes it a True which satisfy the condition to execute.