#!/usr/bin/env
python
# -*- coding: utf-8 -*-
#python2.7x
#random_weight.py
#author: orangleliu@gmail.com 2014-10-11
'''''
每个元素都有权重，然后根据权重随机取值
输入 {"A":2, "B":2, "C":4, "D":10, "E": 20}
输出一个值
'''
import random
import collections as coll
data = {"A":2, "B":2, "C":4, "D":6, "E": 11}
#第一种 根据元素权重值 "A"*2 ..等，把每个元素取权重个元素放到一个数组中，然后最数组下标取随机数得到权重
def list_method():
all_data = []
for v, w in data.items():
temp = []
for i in range(w):
temp.append(v)
all_data.extend(temp)
n = random.randint(0,len(all_data)-1)
return all_data[n]
#第二种 也是要计算出权重总和，取出一个随机数，遍历所有元素，把权重相加sum，当sum大于等于随机数字的时候停止，取出当前的元组
def iter_method():
total = sum(data.values())
rad = random.randint(1,total)
cur_total = 0
res = ""
for k, v in data.items():
cur_total += v
if rad<= cur_total:
res = k
break
return res
def test(method):
dict_num = coll.defaultdict(int)
for i in range(100):
dict_num[eval(method)] += 1
for i,j in dict_num.items():
print i, j
if __name__ == "__main__":
test("list_method()")
print "-"*50
test("iter_method()")
