I'm creating a loop which executes every 5 seconds, starting at the startTime variable and ending at the stopTime variable. However, the code below is disregarding the minutes within my startTime and endTime variables and only executing on the hour. For example, even though my startTime is '1130', the code is executing 11:05, rather than ending the loop. I have the same problem with the endTime variable. If the current time is 12:45, the code still executes even though the endTime variable is '1230'. The code will stop executing at '1300'.
frequency = 5
startTime = '1130'
endTime = '1230'
while True:
now = datetime.now().strftime('%H:%M:%S')
if startTime <= now <= endTime:
print('Loop is working. Time is: ',now)
time.sleep(frequency)
else:
print('Loop is stopped')
break
I live in Central Time, so I tried switching to Eastern timezone by modifying the "now" variable to:
now = datetime.now(timezone('US/Eastern')).strftime('%H:%M:%S.%f %Z')
but I still get the same problem when I substitute eastern times with startTime and endTime when using the eastern datetime.now().
Is executing code at a precise minute possible with strftime()?
EDIT: (this is now the answer to the real question (oops))
If you want to wait till for example 11:30 (which was the real question) you can calculate the time (in seconds) the program should sleep (and let it sleep for that time):
def wait_till(hour, minute, second=0):
# get system time (and date)
now_time = datetime.datetime.now()
# create time point we are waiting for (this year, this month and this day)
wait_till_time = datetime.datetime(year=now_time.year, month=now_time.month, day=now_time.day, hour=hour, minute=minute, second=second)
# calculate time we want to wait for and convert to seconds
wait_for = (wait_till_time - now_time).total_seconds()
# check if it's going to be tomorrow (if we would sleep for a negative amount of seconds)
if wait_for < 0:
# add one day
wait_till_time = wait_till_time.replace(day=now_time.day+1)
# recalculate (not very beautiful, but i don't know a better way)
wait_for = (wait_till_time - now_time).total_seconds()
# printing this waiting time (in seconds)
print("waiting for",wait_for,"seconds")
# sleeping for that time
time.sleep(wait_for)
# printing the new now time, so we can see how accurate it is
print("its now",datetime.datetime.now())
and say for example:
wait_till(20, 24) # waiting till 20:24 (today)
and get:
waiting for 15.32297 seconds
its now 2019-03-11 20:24:00.003857
which is pretty darn close to what we wanted (20:24:00.000000) and this delay is probably only caused by the calculation lag of formatting the string.
(The old stuff ...)
if it's not important that it takes 100% 5s (but rather 100.04546642303467% --> it will get off a little bit every time) you can just do
import time
frequency = 5 #every 5 seconds
start_time = time.time()
while 1:
elspsed_time = time.time() - start_time
print(elspsed_time)
time.sleep(frequency)
but if you need the 100% you can try this autocorrecting solution:
import time
from threading import Timer
frequency = 5 #every 5 seconds
start_time = time.time()
def what_to_do_after_5s():
elapsed_time = time.time() - start_time
print(elapsed_time)
# next call
Timer(5.0 - (elapsed_time - int(elapsed_time)), what_to_do_after_5s, ()).start()
what_to_do_after_5s()
and we can see that it autocorrects:
0.0
5.000170707702637
10.000272989273071
15.000539064407349
20.001248836517334
25.00046443939209
30.000929355621338
35.00142860412598
40.0007688999176
45.00128436088562
50.00045442581177
55.000683069229126
60.00123882293701
65.00095415115356
70.0015127658844