Python - lists intersection, difference, union and symmetric difference practical examples

In this article, we would like to show you how to implement instersection, difference, union and symmetric difference functions for lists in Python.

Practical example:

def difference(input_list1, input_list2):
    return list(set(input_list1) - set(input_list2))


def symmetric_difference(input_list1, input_list2):
    return list(set(input_list1) ^ set(input_list2))


def intersection(input_list1, input_list2):
    return [item for item in input_list1 if item in input_list2]


def union(input_list1, input_list2):
    return list(set(input_list1) | set(input_list2))


# Usage example:

list1 = [1, 2, 3, 4]
list2 = [1, 2, 5, 6]

# Warning: the order matters!
print(difference(list1, list2))  # [3, 4]
print(difference(list2, list1))  # [5, 6]

print(symmetric_difference(list1, list2))  # [3, 4, 5, 6]
print(intersection(list1, list2))          # [1, 2]
print(union(list2, list1))                 # [1, 2, 3, 4, 5, 6]