[Python] 2 implementations of random numbers based on weights

Problem:

For example, we want to choose a number from different provinces, each province's weight is not the same, direct selection of random number is definitely not possible, you need a model to solve the problem.

Simplify to the following questions:

The key for the dictionary is the province, and value is the weight, and we now need a function that selects a province based on the weights each time.

{"A": 2, "B": 2, "C": 4, "D": Ten, "E": 20}

Solve:

This is the most can think and can see the version, do not know that there is no more efficient and useful algorithms.

#!/usr/bin/env python#-*-coding:utf-8-*-#python2.7x#random_weight.py #author: [email protected] 2014-10-11 ' Each element has weights, then enter {"A" according to the random value of the weight: 2, "B": 2, "C": 4, "D": Ten, "E": 20} Outputs a value "' Import randomimport collections as Colldata = {" A ": 2, "B": 2, "C": 4, "D": 6, "E": one} #第一种 according to the element weight value "A".        And so on, each element takes a weight element into an array, and then the most array subscript random number gets the weight 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 is also to calculate the sum of weights, take out a random number, traverse all elements, add the weights sum, when the sum is greater than or equal to the random number when the stop, remove the current tuple 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: 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 ()")

Results of one execution

A 4C 14B 7E 44D--------------------------------------------------a 8C 16B 6E 43D 27

Ideas:

Ideas are very primitive can refer to the following connection, there are other good ways to communicate together!!

Code: https://gist.github.com/orangle/d83bec8984d0b4293710

Reference:

http://jzkangta.iteye.com/blog/1326302

http://blog.csdn.net/ajian005/article/details/19301689

This article is derived from "Orangleliu notebook " Blog, be sure to keep this source http://blog.csdn.net/orangleliu/article/details/39997489

[Python] 2 implementations of random numbers based on weights