Count iterations in while loop

Question

Is there a way in Python to automatically add an iteration counter to a while loop?

I'd like to remove the lines count = 0 and count += 1 from the following code snippet but still be able to count the number of iterations and test against the boolean elapsed < timeout:

import time

timeout = 60
start = time.time()

count = 0
while (time.time() - start) < timeout:
    print 'Iteration Count: {0}'.format(count)
    count += 1
    time.sleep(1)

You may be thinking of enumerate which does this for for loops, but I don't know of any solution for while other than what you have. — Two-Bit Alchemist
– Two-Bit Alchemist, Commented Jul 27, 2016 at 18:40
Unfortunately, Python doesn't allow assignment statements in an expression. Otherwise, this could be a lot cleaner. — Alex W
– Alex W, Commented Jul 27, 2016 at 19:14

user2357112 · Accepted Answer · 2016-07-27 18:50:51Z

14

The cleanest way is probably to convert this to an infinite for loop and move the loop test to the start of the body:

import itertools

for i in itertools.count():
    if time.time() - start >= timeout:
        break
    ...

answered Jul 27, 2016 at 18:50

user2357112

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Vincent Savard · Accepted Answer · 2016-07-27 18:52:45Z

3

You could instead move the while loop to a generator and use enumerate:

import time

def iterate_until_timeout(timeout):
    start = time.time()

    while time.time() - start < timeout:
        yield None

for i, _ in enumerate(iterate_until_timeout(10)):
    print "Iteration Count: {0}".format(count)
    time.sleep(1)

answered Jul 27, 2016 at 18:52

Vincent Savard

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