a – 2 – random

import random
                1 生成随机数

random 模块 
    random.randint()
                1 产生随机整数，介于两者之间，包含两个端点
                2 def randint(a, b)
                3 Return random integer in range [a, b], including both end points.
    random.random()
                1 [0, 1) 的 随机数
                2 def random()
                3 random() -> x in the interval [0, 1)
    random.choice()
                1 非空序列中选一个随机数
                2 def choice(seq)
                3 Choose a random element from a non-empty sequence.
                4 random.choice([1, 2, 3, 4, 5])