将set()结果输出值打印成换行符

使用 join

print('\n'.join(a & b) or "No common elements")

此外,如前所述,如果每个字符中都有换行符,则可以对空字符串进行联接,以获得相同的结果:

print(''.join(a & b) or "No common elements")

print('\n'.join(s.strip('\n') for s in a & b) or "No common element")

此外,所有这些都有效,因为join在没有可循环的内容时返回空字符串:

In [60]: '\n'.join(set() & set())
Out[60]: ''

False 在python中。

set intersection

def print_common_members(a, b):
    """
    Given two sets, print the intersection, or "No common elements".
    """
    inter = a.intersection(b)
    if inter:   # empty sets are Falsy, non empty sets are Truthy 
        for elt in inter:
            print(elt)
    else:
        print("No common elements")
    
a = {1, 2, 3}
b = {2, 3, 4}
c = {7, 8, 9}
print_common_members(a, b)
print()
print_common_members(a, c)

输出:

2
3

No common elements