python内置模块collections
1、namedtuple
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from collections import namedtuple
websites = [
('Sohu', 'http://www.google.com/', u'张朝阳'),
('Sina', 'http://www.sina.com.cn/', u'王志东'),
('163', 'http://www.163.com/', u'丁磊')
]
Website = namedtuple('Website', ['name', 'url', 'founder'])
mywebsite = Website('ading', 'http://blog.65535.fun', u'林天来')
print(mywebsite.name)
print(mywebsite.url)
print(mywebsite.founder)
for website in websites:
website = Website._make(website)
print website
2、deque
In [1]: from collections import deque
In [2]: mydeque = deque(maxlen=10)
In [3]: mydeque.maxlen
Out[3]: 10
In [4]: mydeque.append(1)
In [5]: mydeque.append(10)
In [6]: mydeque
Out[6]: deque([1, 10])
In [7]: mydeque.appendleft('a')
In [8]: mydeque.appendleft('b')
In [9]: mydeque
Out[9]: deque(['b', 'a', 1, 10])
In [10]: mydeque.pop()
Out[10]: 10
In [11]: mydeque
Out[11]: deque(['b', 'a', 1])
In [12]: mydeque.popleft()
Out[12]: 'b'
In [13]: mydeque
Out[13]: deque(['a', 1])
deque 还有常用的方法 :copy,reverse, insert, clear
3、OrderedDict
使用dict时,在遍历字典时是无法指定key的顺序的,但OrderedDict 是可以的
In [1]: from collections import OrderedDict
In [2]: od = OrderedDict
In [3]: od = OrderedDict()
In [4]: od['aa'] = 11
In [5]: od['bb'] = 22
In [6]: od['cc'] = 33
In [7]: od
Out[7]: OrderedDict([('aa', 11), ('bb', 22), ('cc', 33)])
4、defaultdict
默认值是在调用difaultdict 时传入一个可调用函数。
In [1]: from collections import defaultdict
In [2]: df = defaultdict(lambda: 'aa')
In [3]: df['key1'] = 11
In [4]: df['key2']
Out[4]: 'aa'
In [5]: df
Out[5]: defaultdict(
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转载来源:http://scyanting.com/article/psopjs.html