>>> from operator import itemgetter

# list使用下标进行返回

>>> a

[('a', 1), ('b', 2), ('c', 3), ('d', 4)]

>>> itemgetter(1)(a) # 获取a中下标为1的元组

('b', 2)

>>> itemgetter(1,3)(a) # 同时获取多个元组

(('b', 2), ('d', 4))

# dict使用键来返回

>>> a = {'one': 1, 'two':2, 'three':3}

>>> itemgetter('one')(a)

1

>>> itemgetter('one', 'two')(a)

(1, 2)

from operator import attrgetter

class User(object):

def __init__(self, uid):

self.uid = uid

def __repr__(self):

return 'User({})'.format(self.uid)

users = [User(25), User(14), User(100)]

print(sorted(users, key=attrgetter('uid')))

"""

D:\笔记\python电子书\Python3>python index.py

[User(14), User(25), User(100)]

"""

class User(object):

def __init__(self, uid):

self.uid = uid

def __repr__(self):

return 'User({})'.format(self.uid)

users = [User(25), User(14), User(100)]

print(sorted(users, key=lambda u: u.uid))

"""

D:\笔记\python电子书\Python3>python index.py

[User(14), User(25), User(100)]

"""