利用random实现随机选择指定个数的元素

代码：

#! /usr/bin/env python#coding=utf-8import randomdef rand_test(res, req_num):    host_pool = []    for item in res:        host_pool.append(item[4])    print host_pool    slice = random.sample(host_pool, req_num)    print slice    return sliceif __name__ == '__main__':    res=[[1,2,1,2,'compute22'], [1,2,1,2,'compute23'], [1,2,1,2,'compute24'], [1,2,1,2,'compute25'],               [1,2,1,2,'compute26'], [1,2,1,2,'compute27'], [1,2,1,2,'compute28'], [1,2,1,2,'compute29']]    req_num = 3    rand_test(res, req_num)

结果：

['compute22', 'compute23', 'compute24', 'compute25', 'compute26', 'compute27', 'compute28', 'compute29']result:['compute24', 'compute22', 'compute23']