python比较两个列表之间的差异

Question

我有两个这样的列表:

newList = (
    (1546, 'John'),
    (8794, 'Michael'),
    (892416, 'Dave'),
    (456789, 'Lucy'),
    )

oldList = (
    (1546, 'John'),
    (8794, 'Michael'),
    (892416, 'Dave'),
    (246456, 'Alexander')
    )

我想要一个比较两个列表的功能.它会是这样的:

def compare(new, old):
    print('Alexander is not anymore in the new list !')
    print('Lucy is new !')
    return newList 

我想与每个人的身份比较独特.

编辑:结果将是我的功能比较.它打印出差异.我不知道如何开始

Answer 1

您可以将列表转换为集合并消除差异

n = set(l[1] for l in newList)
o = set(l[1] for l in oldList)
print n - o # set(['Lucy'])
print o - n # set(['Alexander'])