Returns the symmetric difference between two lists, after applying the provided function to each list element of both.
Create a set by applying fn to each element in every list.
Use a list comprehension in combination with fn on each of them to only keep values not contained in the previously created set of the other.
defsymmetric_difference_by(a, b, fn):
(_a, _b)=(set(map(fn, a)),set(map(fn, b)))return[item for item in a if fn(item)not in _b]+[item
for item in b if fn(item)not in _a]
from math import floor
symmetric_difference_by([2.1,1.2], [2.3,3.4], floor)# [1.2, 3.4]
