python 一个集合中获得最大或者最小的 N 个元素列表

怎样从一个集合中获得最大或者最小的 N 个元素列表?

heapq 模块有两个函数:nlargest() 和 nsmallest() 可以完美解决这个问题。

import  heapq

mums = [1,2,23,4,-4,22]

heapq.nlargest(3,nums)#prints[23,22,4]

heapq.nsmallest(3,nums) #prints[-4,1,2]

portfolio = [

{'name': 'IBM', 'shares': 100, 'price': 91.1}, {'name': 'AAPL', 'shares': 50, 'price': 543.22}, {'name': 'FB', 'shares': 200, 'price': 21.09}, {'name': 'HPQ', 'shares': 35, 'price': 31.75}, {'name': 'YHOO', 'shares': 45, 'price': 16.35}, {'name': 'ACME', 'shares': 75, 'price': 115.65}

]

cheap = heapq.nsmallest(3, portfolio, key=lambda s: s['price']) 

expensive = heapq.nlargest(3, portfolio, key=lambda s: s['price'])

heapq 标准库连接

https://www.jianshu.com/p/801318c77ab5