Python Number generator of multiple ranges.

Question

How would I generate one random number from multiple ranges, example (0-10) and (20-30)

Answer 1

A different approach, that is doing this:

- in the inner choice(), the various ranges are stored in a list. choice() selects one of these range() objects and returns it to the outer choice
- in the outer choice the selected object from the inner expression will give a number back that wil be the result:

from random import choice
print(choice(choice([range(0,15), range(30,45), range(60,75)])))

[edited] added an other version that has a better readabilty than the other ones.

from random import choice
rngs = [[0,15], [30,40], [90,110]]
res = [range(*x) for x in rngs]
print(choice(choice(res)))

Answer 2

Russ , may be you can shorten this by using:

lst = list(range(10,20)) + list(range(35,50))

Answer 3

You could put all ranges into a list, then choose a number from the list at random.

import random

rand_list = []
rand_list += list(range(11))
rand_list += list(range(20, 31))
print(random.choice(rand_list))

Answer 4

Russ , you are absolutely right when ranges are too different in size. This was an issue i was not aware of. Thanks for you helpful comment.
Also thanks for your last comment.

Answer 5

Lothar I had considered that before posting my answer but if the ranges are of different sizes, it would create an uneven distribution of probabilities over all the numbers.

Great code though! 👍

Answer 6

Lothar Or this for more ranges..?

lst = []
[lst.extend(range(*i)) for i in ((10,21), (30,45), (60,85))]

Answer 7

from random import randrange, randint

print(randrange(8, 21, 2)) # (start, stop, step)
# or
print(randint(4, 17))

Answer 8

Thank you!