python-day20--collections模块

1.namedtuple: 生成可以使用名字来访问元素内容的tuple

>>> from collections import namedtuple
>>> Point = namedtuple(‘Point‘, [‘x‘, ‘y‘])
>>> p = Point(1, 2)
>>> p.x
>>> p.y

2.OrderedDict: 有序字典

>>> from collections import OrderedDict
>>> d = dict([(‘a‘, 1), (‘b‘, 2), (‘c‘, 3)])
>>> d # dict的Key是无序的
{‘a‘: 1, ‘c‘: 3, ‘b‘: 2}
>>> od = OrderedDict([(‘a‘, 1), (‘b‘, 2), (‘c‘, 3)])
>>> od # OrderedDict的Key是有序的
OrderedDict([(‘a‘, 1), (‘b‘, 2), (‘c‘, 3)])

3.defaultdict: 带有默认值的字典

from collections import defaultdict

values = [11, 22, 33,44,55,66,77,88,99,90]

my_dict = defaultdict(list)

for value in  values:
    if value>66:
        my_dict[‘k1‘].append(value)
    else:
        my_dict[‘k2‘].append(value)

defaultdict字典解决方法