元素的多重排序

应用场景：渲染用户界面时，因为关键的消息和特殊的事件应该优先显示在其他信息之前。

numbers = [8, 3, 1, 2, 5, 4, 7, 6]  //原始数据
group = {8, 3, 5, 7}  //优先级高的数据，
def sort_priority(numbers, group):
    found = False

    def helper(x):  
        nonlocal found   
        if x in group:
            found = True
            return 0, x
        return 1, x

    numbers.sort(key=helper)
    return found
res = sort_priority(numbers, group)
print(res, numbers)  //打印

完善用类方法实现

# 优化 类方法
class Sorter:
    def __init__(self, group):
        self.group = group
        self.found = False

    def __call__(self, x):
        if x in self.group:
            self.found = True
            return 0, x
        return 1, x


sorter = Sorter(group)
numbers.sort(key=sorter)
print(numbers)
assert sorter.found is True

输出结果

True [3, 5, 7, 8, 1, 2, 4, 6]
[3, 5, 7, 8, 1, 2, 4, 6]

作者：朱海波