Random events with an average frequency

random_drops.py

''' Written in response to u/thisisjusttofindajob's Reddit post 

https://www.reddit.com/r/learnpython/comments/xnq9bv/how_to_render_objects_randomly_in_time/

about random timings with an average frequency.
'''

from time import perf_counter
import random

# program parameters
total_duration = 10
objects = range(5) # your list of objects
drops_per_second = 2
drop_check_period = 0.1 # must be < (1 / drops_per_second)

# state and update variables
num_objects = len(objects)
drop_index = random.randrange(num_objects) # could also start at 0
drop_thresh = drop_check_period * drops_per_second
drop_count = 0
expected_count = drops_per_second * total_duration

# timing variables and run loop
start = perf_counter()
end = start + total_duration
last_drop_check = start - drop_check_period
while (now := perf_counter()) < end:
    if now > last_drop_check + drop_check_period:
        if random.random() < drop_thresh:
            drop = objects[drop_index]
            drop_count += 1
            print(drop) # start a drop
            drop_index = (drop_index + 1) % num_objects
        last_drop_check = now
    ... # your other updates (should take less than drop_check_period)

print(f'dropped {drop_count} objects, expected {expected_count}.')