How can I make a 3 second countdown without using the time.sleep() function

Question

I need a function to start a countdown from 3 for a rock, paper, scissors game which uses the webcam, I can't use time.sleep() as the script reads the input from the camera and then compares it with the computer's choice without stopping and time.sleep() stops the script from running

Currently, my function counts up from zero, and also prints multiple iterations of the same number.

I also feel like the function is overcomplicated, are there any simpler methods?

Code:

def countdown():

     countdown_time = 3
     start_time = time.time()

     while (time.time() - start_time) < countdown_time:
        print(round(time.time() - start_time))
        if (time.time() - start_time) >= countdown_time:
            break

Ideally it should just print:

3
2
1

But it prints something more like this:

1
1
1
2
2
2
3
3
3

Answer 1

I think this what you are looking for:

from time import sleep

def countDown():
    for i in range(3, 0, -1):
        print(i)
        sleep(1)
        
countDown()

You are saying that you can't use the time.sleep() as that particular function won't start the program which is wrong. It works here just fine.