以一定的概率将 2 个值随机放入数组中答案

【问题标题】：Place 2 values randomly in array with certain probability以一定的概率将 2 个值随机放入数组中
【发布时间】：2020-06-19 08:30:11
【问题描述】：

我想通过分配列表seq=[30,170] 的值，在python 中创建一个长度为24 的随机数组。所以我想要一个看起来像a=[30,30,30,170,30,170,...] 的数组。问题是，这些值不应该完全随机分配，而是以一定的概率分配。在这种情况下，如果第一个值为 30（或 170），则下一个值为 30（或 170）的概率应该是 90%，下一个值为 170（或 30）的概率应该是10%。

有人知道怎么做吗？目前我只发现如何随机排列它们。谢谢！！

import random
seq=[30,170] 
a = random.choices(seq,k=24)

【问题讨论】：

标签： python random probability

【解决方案1】：

您可以向random.choices(population, weights=None, *, cum_weights=None, k=1)提供权重。

您需要迭代地执行此操作，以便在查找您需要使用的重量时能够引用最后一个值：

import random

seq = [30, 170] 

# weight lookup
wgt = {30: (90, 10), 170:(10, 90)}

r = []

for _ in range(24):
    if not r:
        # need some initial value: 50/50
        r.append(random.choice(seq))
    else:          
        # k == 1, using correct weights from lookup, use only single value and add it
        r.append(random.choices(seq, weights=wgt[r[-1]], k=1)[0])

print(r)

8 次运行的输出：

[170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170]

[30, 30, 30, 30, 30, 30, 170, 170, 170, 170, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30]

[30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30]

[30, 30, 30, 30, 30, 170, 170, 170, 170, 170, 170, 170, 170, 30, 30, 170, 170, 170, 170, 170, 170, 170, 170, 170]

[170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 30, 30, 30, 170, 170, 170, 170]

[170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 170, 30, 30, 30, 30, 30, 30, 30, 30, 30]

[30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30]

[30, 30, 170, 170, 30, 170, 170, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30]

您也可以自己提供权重：

seq = [30,170]
w = {30: (30,30,30,30,30,30,30,30,30,170),           # if  30: use 9 * 30 + 1 * 170
     170:(30,170,170,170,170,170,170,170,170,170)}   # if 170: use 9 * 170 + 1 * 30

r = []
for _ in range(24):
    if not r:
        r.append(random.choice(seq))
    else:          
        r.append(random.choice(w[r[-1]]))

【讨论】：

这正是我想要的，非常感谢！