How do I ensure that a Python while-loop takes a particular amount of time to run?

Question

I\'m reading serial data with a while loop. However, I have no control over the sample rate.

The code itself seems to take 0.2s to run, so I know I won\'t be able to

Answer 1

At the beginning of the loop check if the appropriate amount of time has passed. If it has not, sleep.

# Set up initial conditions for sample_time outside the loop
sample_period = ???
next_min_time = 0
while True:
    sample_time = time.time() - zero
    if sample_time < next_min_time:
        time.sleep(next_min_time - sample_time)
        continue
    # read and print a line
    sample_value = ser.readline()
    sample_line = str(sample_time)+','+str(sample_value)
    outfile.write(sample_line)
    print 'time: {}, value: {}'.format(sample_time, sample_value)
    next_min_time = sample_time + sample_period