python dict 按照value排序的试验

一般采取sorted自建函数进行排序，但考虑到Counter.most_common 可以取到前若干个，那么不妨实现并比较下二者的效率

# coding:utf - 8
import copy
import random
import sys
import time
from collections import Counter
from collections import defaultdict
from operator import itemgetter

reload(sys)
sys.setdefaultencoding("utf-8")

thresh = 100000
mapper = defaultdict(int)
random_creator = random.Random()
const = 10000
for index in xrange(thresh):
# type of float
random_number = random_creator.random()
mapper[int(random_number * const)] += 1
mapper_1 = copy.deepcopy(mapper)
mapper_2 = copy.deepcopy(mapper)
# counter
start = time.time()
counter = Counter(mapper_1)
print counter.most_common(const)
print str(time.time() - start)
# sorted
start = time.time()
print sorted(mapper_2.iteritems(), key=itemgetter(1), reverse=True)
print str(time.time() - start)

在一台6500的机器上，输出如下：

[(9298, 25), (647, 22), (848, 22), (1365, 22), (2036, 22), (3566, 22)……

0.150000095367

[(9298, 25), (647, 22), (848, 22), (1365, 22), (2036, 22), (3566, 22)……

0.138999938965

看起来还是sorted更胜一筹，代码实现可供参考，多谢捧场