Here's a brain tickler that I have been trying to solve for a couple of hours. The code below takes two lists of integers and returns a list of the items in the 1st list but not the second AND the items in the 2nd list that are not in the first.
def difference(lista, listb):
output_list = []
for element in range(len(lista)):
if lista[element] not in listb:
output_list.append(lista[element])
for element in range(len(listb)):
if listb[element] not in lista:
output_list.append(listb[element])
return output_list
list1 = [1, 2, 4, 5, 6]
list2 = [1, 2, 5, 7, 9]
print(f"\nYour lists are {list1} and {list2}, the items in the first, but not in the second.")
The code works, but I am sure there is a way to do this with list comprehension. I have tried:
output_list = [element for element in lista if element not in listb] + [element for element in listb if element not in lista]
This doesn't work. Any clues very gratefully received!
I mean, u can do this in various ways:
list1 = [1, 2, 4, 5, 6]
list2 = [1, 2, 5, 7, 9]
using list comprehension:
[x for x in list1 if x not in list2] + [y for y in list2 if y not in list1]
using python's set + ord:
list(set(list1) ^ set(list2))
using the python's filter function:
list(filter(lambda x: x not in list2, list1)) + list(filter(lambda x: x not in list1, list2))
using python's map function:
from_1 = list(map(lambda x: x if x not in list2 else None, list1))
from_2 = list(map(lambda x: x if x not in list1 else None, list2))
output = [x for x in from_1 + from_2 if x is not None]
or even using itertools.chain:
[item for item in chain(list1, list2) if (item in list1 and item not in list2) or (item in list2 and item not in list1)]