Operator

尹奉

2023年7月5日 12:11:55

Operator | Ghost in the Shell Wiki

Python 标准库 operator 提供了itemgetter和attrgetter。

f = attrgetter('name')的语义同f = lambda b: b.name，f(b)会返回b.name。还支持f = attrgetter('name.first', 'name.last')，这时f(b)会返回(b.name.first, b.name.last)。itemgetter同理，不过b.name要换成b['name']。

排序、查找可能用到这些东西。

from collections import namedtuple
from operator import attrgetter
from bisect import bisect

Movie = namedtuple('Movie', ('name', 'released', 'director'))

movies = [
    Movie('Jaws', 1975, 'Spielberg'),
    Movie('Titanic', 1997, 'Cameron'),
    Movie('The Birds', 1963, 'Hitchcock'),
    Movie('Aliens', 1986, 'Cameron')
]

by_year = attrgetter('released')
movies.sort(key=by_year)

# Find the first movie released after 1960
movies[bisect(movies, 1960, key=by_year)]

operator.attrgetter(attr) - operator — Standard operators as functions — Python 3.11.4 documentation

Examples - bisect — Array bisection algorithm — Python 3.11.4 documentation