How to write a one-liner generator expression for an infinite stream of odd numbers from 1 to 99?

Question

I am trying to write a one-liner Python generator expression that provides an infinite stream of odd random numbers between 1 and 99 inclusively.

Can anyone please help me?

Answer 1

import random as rdm

g = (1+2*rdm.randint(0, 49) for r in iter(int, 1))

rdm.randint(0, 49) gives you a random int between 0 and 49. So (1+2*rdm.randint(0, 49) gives you a random number odd number between 1 and 99.

iter(int, 1) is an infinite iterator (which is always 0 and just used to keep the generator going).

Answer 2

You can use itertools.count() to make infinite loop and itertools.filterfalse to filter values you don't need:

from random import randint
from itertools import count, filterfalse

f = filterfalse(lambda i: i % 2 == 0, [(yield randint(1, 99)) for i in count()])

for i in f:
    print(i)

Prints:

...
61
21
91
77
39
... and so on

Version 2 (without itertools):

from random import randint

for val in (i for i in iter(lambda: randint(1, 99), 0) if i % 2 != 0):
    print(val)

Answer 3

Do this: (Python 3)

stream = (lambda min_, max_: type("randint_stream", (), {'__next__': (lambda self: 1+2*__import__('random').randint(min_-1,max_//2))}))(1,99)()

Get randint with next(stream).
Change min and max by changing the (1,99).
Real 1 line! Can change min & max!

                           =========== Adding ===========  

The version above isn't a strict generator -- it's another class. Version 2:

stream = (lambda min_, max_: (1+2*__import__('random').randint(min_-1,max_//2) for x in iter(int, 1)))(1,99)

Use next() to get random odd number.
Change min and max by changing the (1,99).