如何在python中生成随机数字序列？

Question

如何产生1,2,3的随机序列，条件是80％的数字将为1，15％将为2和5％将为3？

Answer 1

Use random to get a random number in [0,1) and map your outputs to that interval.

from random import random

result = []

# Return 100 results (for instance)
for i in range(100):

    res = random()

    if res < 0.8:
        result.append(1)
    elif res < 0.95:
        result.append(2)
    else:
        result.append(3)

return result

This is a trivial solution. You may want to write a more elegant one that allows you to specify the probabilities for each number in a dedicated structure (list, dict,...) rather than in a if/else statement.

But then you might be better off using a dedicated library, as suggested in this answer . Here's an example with scipy's stats.rv_discrete

from scipy import stats
xk = np.arange(1, 4)
pk = (0.8, 0.15, 0.05)
custm = stats.rv_discrete(name='custm', values=(xk, pk))
# Return 100 results (for instance)
return custm.rvs(size=100)

Answer 2

This should do the trick

import random

sequence = []

desired_length = n # how many numbers you want
for i in range(desired_length):
    random_value = random.random()
    if random_value < .8:
        sequence.append(1)
    elif random_value < .95:
        sequence.append(2)
    else:
        sequence.append(3)

print sequence