how to run two while loops inside a while loop

Question

interval_sec = 15.0
t_end = time.time() + interval_sec
episode = 0
while True:

    while episode < 3:
        print('Episode %s' % episode)
        episode += 1

    while time.time() < t_end:           
        print("hi")

I've tried everything. I tried using a for loop (for episode in range(0,3)), deleting the episode var and even defining the

while episode < 3:
    print('Episode %s' % episode)
    episode += 1

as a function in the loop.

The expected output I am trying to achieve, in pseudo code, is:

the first nested while loop (while episode < 3:) prints out

Episode 0
Episode 1
Episode 2

then the second nested while loop prints out "hi" for 15 seconds

and then the first nested while loop should print out

Episode 0
Episode 1
Episode 2

and then the print "hi" for 15 seconds again and so forth. It should repeat this process forever (hence the while True: loop).

Looking for a fix that I haven't tried. Much appreciated

Answer 1

Your counting logic for the first loop is wrong. Looks at the basic pieces of initialization, test, and increment:

episode = 0
while episode < 3:
    ...
    episode += 1

This forms the basic counting loop. The problem is that you separated the pieces, placing them in different logic blocks:

episode = 0
while True:       # This is fatal to your counting loop's operation
    while episode < 3:
        ...
        episode += 1

Python gives you tools to help with this. The for statement gives you a counting loop in one convenient package:

for episode in range(3):
    ....

Now it's trivial to keep the loop pieces together.

Note that you have the same problem with the ending time: you need to recompute it for each iteration of the outer while loop, so that code should come just after the while True statement.