lst1 = [1, 3, 7]

lst2 = [3, 5, 4]

a = [x for x in lst1 if x in lst2]

b = [y for y in (lst1 + lst2) if y not in a]

print(a)

print(b)

lst1 = [1, 3, 7]

lst2 = [3, 5, 4]

a = []

b = []

for i in lst1:

    for j in lst2:

        if i == j:

            a.append(i)

for k in (lst1 + lst2):

    if k not in a:

        b.append(k)

print(a)

print(b)

lst1 = [1, 3, 7]

lst2 = [3, 5, 4]

a = set(lst1)   # {1, 3, 7}

b = set(lst2)   # {3, 5, 4}

# 交集 a & b  包含集合a和集合b中的公共元素

# print(a & b)      # {3}

# 对称差集 a ^ b    包含集合a和集合b中不重复的所有元素

# print(a ^ b)      # {1, 4, 5, 7}

print(list(a & b))  # [3]

print(list(a ^ b))  # [1, 4, 5, 7]

# 并集 a | b  包含集合a和集合b中所有的元素

# 差集 a - b  包含集合a中有的集合b中没有的元素

x = a.symmetric_difference(b)

y = a.symmetric_difference_update(b)  # 自我更新不返回对象,即a ^= b

print(x)    # {1, 4, 5, 7}

print(y)    # None

print(a)    # {1, 4, 5, 7}