Simple countdown programs to print "3, 2, 1, Action!" using while loop

Question

My program is a simple while loop making a countdown starting from 3 and shouts "Action!" upon reaching zero and then breaks. I would like to know which of the following ways is better in means of clarity and functionality. I am aware that there are other ways to achieve the same thing. I would like to hear your thoughts and suggestions.

countDown = 3
while (countDown >= 0):
    print(countDown)
    countDown = countDown - 1
    if countDown == 0:
        print("Action!")
        break

or

countDown = 3
while (countDown >= 0):
    if countDown != 0:
        print(countDown)
        countDown = countDown - 1
    else:
        print("Action!")
        break

Answer 1

Why does it has to be a while?

Maybe it is preference but for loops look cleaner.

Reversing can be done by using reversed function which reverses a iteration

countdown = 3
for count in reversed(range(1, countdown+1)):
    print(count)
print('action!')

Or you could use the step parameter in range(start, end, step) and rewrite the for loop to

for count in range(countdown, 0, -1):

Answer 2

You can get rid of some instructions by writing this instead:

count_down = 3
while (count_down):
   print(count_down)
   count_down -=  1
print('Action!')

Note that I have replaced countDown by count_down to comply with PEP8' naming conventions.

Code explanation:

count_down -= 1 is equivalent to count_down = count_down - 1. You can read more on Python basic operators.

You do not need to check within the while loop if count_down reached the 0 value because it is already done when you coded while (countDown>=0). I mean you are duplicating the checking. In order to keep DRY, I just decrement the value of count_down by 1 and the break instruction is done by default as I am testing while(count_down) meaning if count_down != 0 in this context (because it also means while count_down is not False or None).

Answer 3

I think your first example is better in terms of clarity, although you could replace while (countDown >= 0): with while (countDown > 0):, allowing you to remove your break statement.

Ex:

countDown = 3
while (countDown > 0):
    print(countDown)
    countDown = countDown - 1
    if countDown == 0:
        print("Action!")

Answer 4

Why not try recursion? Clean and simple.

num = 10

def countdown(num):
    if num == 0:
        print("Action!")
        return
    print(num)
    countdown(num-1)
countdown(num)

Answer 5

count_down = 5

while count_down > 0:

print(count_down - 1)

count_down -= 1

if count_down == 0:

print ("Action!")