List intersection based on function
Returns a list of elements that exist in both lists, after applying the provided function to each list element of both.
- Create a
set
, usingmap()
to applyfn
to each element inb
. - Use a list comprehension in combination with
fn
ona
to only keep values contained in both lists.
def intersection_by(a, b, fn): _b = set(map(fn, b)) return [item for item in a if fn(item) in _b] from math import floor intersection_by([2.1, 1.2], [2.3, 3.4], floor) # [2.1]